Topic 22: Abnormal Labor

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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

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StatPearls [Internet].

Abnormal labor.

Prabhcharan Gill ; Joshua M. Henning ; Karen Carlson ; James W. Van Hook .

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Last Update: June 14, 2023 .

  • Continuing Education Activity

Physicians, advanced practice practitioners, nursing personnel, and midwives must be aware of what constitutes normal versus abnormal labor. Without proper education, skills, and strategies, appropriate management cannot occur, and poor outcomes become likely for birthing mothers and their neonates. Discerning patterns of abnormal labor will allow for proper intervention and management. This will decrease morbidity and mortality and improve patient outcomes. This activity characterizes normal versus abnormal labor and highlights the critical role of the interprofessional birth team in providing optimal care and counseling to the birthing mother and the infant.

  • Differentiate normal and abnormal labor patterns in each stage and phase of labor.
  • Identify the signs and symptoms of abnormal labor, such as protracted, prolonged, or arrested labor.
  • Assess the adequacy of uterine contractions and implement appropriate interventions for dysfunctional labor.
  • Collaborate with other healthcare professionals to manage abnormal labor and coordinate a comprehensive obstetric care plan.
  • Introduction

Normal labor is defined as regular uterine contractions resulting in progressive cervical effacement and dilation. Abnormal labor refers to labor patterns deviating from delineated normal standards. A clear understanding of normal labor progression is essential to recognize dysfunctional labor. [1]

Labor consists of 3 stages. The first stage begins with contractions causing progressive cervical change and concludes with full cervical dilation. The first stage is further divided into latent and active phases. The second stage of labor starts with complete cervical dilation and ends with delivery of the fetus. The third stage begins with delivery of the fetus and ends with placental delivery. [2]  Abnormal labor occurs across all stages and is described as a prolonged, protracted, or arrested progression of labor. [3]  

The stages and phases of labor have specific time intervals used in labor evaluation and interpretation. Ideally, patients are evaluated with or without pelvic examinations every 2 hours to assess labor progress.

  • Latent phase: 0 to 5 cm dilation
  • Active phase: 6 cm dilation to complete cervical dilation
  • Second Stage: uterine contractions along with maternal expulsive efforts leading to the descent of the presenting fetal part and delivery of the fetus
  • Third Stage: time between delivery of the fetus and placental delivery

The following parameters apply to full-term singleton pregnancies and represent the time 95% of patients will complete a given stage or phase of labor. These parameters should be met when classifying labor as abnormal: [1]

First Stage Prolongation, Protraction, and Arrest

  • In nulliparous patients: latent phase duration of more than 20 hours
  • In multiparous patients: latent phase   duration   of   more than 4 hours
  • Due to its variable and slow progression, latent phase prolongation alone is not an indication for cesarean delivery.
  • No cervical dilation after 4 hours of adequate contractions, with ruptured membranes
  • No cervical dilation after 6 hours of inadequate contractions, with ruptured membranes, and despite oxytocin administration

Second Stage Protraction and Arrest

  • For nulliparous patients:  second stage duration of more than 3 hours without an epidural or 4 hours with an epidural
  • For multiparous patients:  second stage duration of more than 2 hours without an epidural or 3 hours with an epidural
  • Longer durations may be appropriate with reassuring maternal and fetal statuses and continued descent of the fetal presenting part.

Third Stage Abnormality

  • Placental retention duration of more than 30 minutes following fetal delivery

Normal labor progression requires consideration of 3 "Ps," representing power, passage, and passenger. Power refers to uterine contractions and maternal expulsive efforts. Passage is the maternal pelvis, and the fetus is the passenger. Abnormal labor progression may be related to one or more of these factors. The size, position, and presentation of the fetus and the adequacy of the maternal pelvis are tested as uterine contractions provide propulsion. Asynclitism or extension of the fetal head, occiput posterior or transverse positions, and mentum or brow presentations may contribute to or be sole etiologies of abnormal labor progression or labor dystocia. [4] Labor abnormalities due to unfavorable fetal or maternal pelvic dynamics may require a cesarean delivery. [5]

Uncommonly, a Bandl ring may be associated with protracted or arrested labor. A Bandl ring is a constriction between the thicker upper contractile and thinner lower uterine segments. It is unclear why this constriction develops during parturition, although prolonged labor and labor dystocia have been suggested as possible causes. [6]

Risk Factors Associated with Abnormal Labor

Maternal Factors

  • Advanced maternal age
  • Chorioamnionitis
  • Epidural analgesia
  • Gestational diabetes
  • Hypertensive disorders
  • Inadequate uterine contractions
  • Lack of supportive care during labor
  • Large weight gain in pregnancy
  • Non-gynecoid maternal pelvimetry
  • Nulliparity
  • Poor hydration and nutrition during labor
  • Postterm pregnancy
  • Short stature

 Fetal Factors

  • High fetal station at full cervical dilation
  • Malpresentation
  • Nonreassuring fetal heart rate tracing [7]
  • Epidemiology

Pelvic shape varies significantly among women, and the fit between the maternal pelvis and fetus is exceptionally tight, unlike in other primates. [8]  Approximately 20% of all labor involves protraction and/or arrest disorders. Disorders of labor are the most common reason for primary cesarean sections. [9]   

Abnormal labor involving true labor dystocia can result in fetal and/or maternal injury and even death. The trend toward more cesarean sections in developed countries has drawn attention to initiatives to minimize primary cesarean sections safely. In this regard, guidelines have been developed to implement more conservative management strategies for the first and second stages of labor. [10]

After the delivery of the fetus, the third stage of labor culminates in the delivery of the placenta. Abnormalities in the third stage can lead to postpartum hemorrhage requiring blood transfusions and, at times, resulting in maternal morbidity and mortality. Postpartum hemorrhage affects approximately 5% of all deliveries. The mean duration of the third stage of labor is 5 to 6 minutes when utilizing active management, and 90% of the third stages take less than 10 minutes. Postpartum hemorrhage is more likely when the third stage lasts more than 18 minutes and significantly more likely when the third stage lasts over 30 minutes. [11]  

  • Pathophysiology

Friedman initially established a labor curve for the first stage of labor; however, it has since been contemporized by Zhang et al. [12]  Recent reference graphs indicate that the latent phase of labor is much longer than initially thought, and the active stage of labor begins at 6 cm of cervical dilation. Induced labor tends to have a longer latent phase in the first stage of labor when compared to spontaneous labor. However, the active phase of the first and second stages do not vary significantly, respective of spontaneous or induced labor. Insufficient uterine activity is the most common reason for a labor abnormality in the first stage of labor. [13]  

Labor is a physically intensive process, and prenatal exercise may play a role in increased uterine contractility. Increased levels of physical activity have been associated with higher levels of oxytocin and decreased needs for induction and augmentation of labor. [14] Maternal inactivity during pregnancy may be associated with prolonged labor. In one particular prospective cohort study, patients who were physically active during pregnancy were less likely to have a prolonged latent phase of labor and more likely to have a shorter active phase of labor. [14]  For these and other reasons, regular prenatal exercise is highly encouraged.

The pathophysiology of abnormal labor is otherwise poorly understood. There is likely a multitude of pathophysiologic etiologies. Current management and intervention are limited and, at times, unsuccessful. Treatment options that target the specific and multiple underlying etiologies may be more successful in treating labor abnormalities. Additional knowledge of diagnostic tools and individualized therapies may lead to future new clinical opportunities. [15]  

  • Toxicokinetics

Oxytocin is a key pharmacologic agent in the augmentation of inadequate uterine contractions and, thus, in treating abnormal labor. It is one of the most commonly used medications in obstetrics. Exogenous oxytocin responsiveness typically commences at 20 weeks of pregnancy and increases with advancing gestational age until 34 weeks, when it appears to plateau. [16]  Oxytocin has a short plasma half-life of 3 to 6 minutes. Oxytocin is utilized during labor as a continuous intravenous infusion.

Adverse maternal effects associated with oxytocin use in labor include flushing, nausea, vomiting, headache, tachycardia, and hypotension. [17] Maternal water retention and hyponatremia rarely occur due to oxytocin use and only in extended exposures to a high oxytocin dose, mainly if administered in hypotonic solutions. This hyponatremia is due to oxytocin's structure being similar to vasopressin and causing cross-reactions with renal vasopressin receptors. [18]  

Uterine tachysystole commonly occurs as a result of oxytocin administration during labor. Tachysystole is 6 or more contractions in a 10-minute window, averaged over 30 minutes. Without adequate time for uterine relaxation between contractions, there is a potential for decreased fetal oxygenation. [17]  Due to the high risk of patient harm when used in error, oxytocin is a high-alert medication. [19]

  • History and Physical

Labor begins with regular uterine contractions resulting in cervical effacement and dilation. An essential piece of the patient history to obtain is the start time of contractions and their occurrence interval. An abdominal examination is a critical component of an obstetric exam as it provides an estimated fetal weight and an assessment of fetal presentation. The continuous monitoring of uterine activity discerns how frequent contractions are occurring. Internal pressure catheter monitoring measures the actual strength of uterine contractions. Fetal heart rate tracing provides reassurance of fetal well-being throughout the labor process.

Digital vaginal exams, conducted at different intervals throughout labor, assess maternal pelvimetry, bony pelvis shape and capacity, as well as cervical effacement and dilation. Serial digital exams are used to assess the fetal position, station, and descent of the presenting part, which is crucial in determining the normal or abnormal progression of labor. [20]

Determining the progression of labor is a critical component of intrapartum care. Maternal uterine activity is assessed by manual palpation, external tocodynamometry, or monitoring with an intrauterine pressure catheter. Using external tocodynamometry, target uterine activity is 3 to 5 contractions in a 10-minute window. Effective contractions last 30 to 40 seconds. Intrauterine pressure assessment using a catheter is commonly used to measure the strength or intensity of uterine contractions in patients with ruptured membranes. This technique involves inserting a catheter through the cervix and into the uterus, which allows for direct measurement of intrauterine pressure. This monitoring employs Montevideo units (MVUs) as measurements of contraction intensity. Montevideo units are calculated by adding the sum of the net contraction pressures over 10 minutes. Adequate uterine activity is targeted at 200-250 MVUs. [21]  Although this method of assessing uterine contractions has limitations, a more useful and accurate system has not yet been devised. Electrohysterography is a recent technique using externally applied abdominal electrodes, which monitors and records electrical voltages generated by myometrial contractions. This method of assessing uterine contractility is not currently part of standard clinical practice. [21]

Evaluating the fetal position is another crucial component of intrapartum care and management. Several studies have shown increased adverse outcomes when the fetus is in an occiput posterior position, including a more prolonged second stage of labor and increased cesarean delivery rate. Randomized trials have shown that manual rotation of the fetus from an occiput posterior position to an occiput anterior position can reduce the length of the second stage of labor. [22]  Manual rotation is more effective than maternal repositioning in labor, and it involves less technical skill and less risk than instrumental rotation. [22]

  • Treatment / Management

Abnormal labor progression is associated with multiple poor maternal and fetal outcomes. Thus active management is imperative to avoid adverse outcomes for the mother and baby. Most labor and delivery units have an established protocol for administering oxytocin to augment inadequate contractions, which entails the administration of the proper medication and dosage and criteria for an incremental increase as clinically warranted. These protocols also include monitoring maternal and fetal status for adverse events. With a protracted or arrested second stage of labor, operative vaginal delivery with either forceps or vacuum by a skilled obstetric professional may be an option to expedite delivery. Cesarean delivery may be necessary in other labor prolongation, protraction, and arrest cases, especially in the active phase of labor's first stage. For a prolonged third stage of labor, manual placenta extraction is, at times, required. 

Prolonged or Protracted First Stage

Latent Phase

  • This phase can be prolonged for many hours and even days. Hence the decision to admit the patient to the hospital depends on various factors, including the status of the cervix, the emotional state of the patient, associated complications, tolerance to pain, and the patient's distance from the hospital. Increased obstetrical interventions have been associated with admission during the latent phase of labor. Therefore, it is imperative to consider the options of admission versus continued outpatient management of the latent phase of labor. [23]  
  • Therapeutic rest may be considered if desired. Morphine may be administered at a dose of 5 to 10 mg intramuscularly and intravenously simultaneously, with a maximum total dose of 20 mg. Alternatively, intramuscular morphine sulfate and promethazine may be utilized. [24]
  • Oxytocin and amniotomy may be helpful in actively treating prolonged latent phase.

Active Phase

  • For women in the active phase of the first stage, oxytocin may be administered, and an amniotomy may be performed.
  • If there has been no cervical change after 4 hours of adequate (>200 Montevideo units) uterine contractions and ruptured membranes or 6 hours with adequate uterine contractions, ruptured membranes, and oxytocin augmentation, it is advisable to proceed with cesarean delivery.
  • However, if labor progresses slowly or normally, oxytocin administration is continued.

Protracted or Arrested Second Stage

  • Oxytocin augmentation is started for minimal (<1 cm) or absent descent after 60 to 90 minutes of maternal pushing with less frequent uterine contractions.
  • Without epidural anesthesia, nulliparous women can push for at least 3 hours and multiparous women for at least 2 hours before considering operative intervention. As long as the fetus continues to descend and/or rotate to a favorable position for spontaneous vaginal delivery and the fetal heart rate pattern is reassuring, any operative intervention should be delayed.
  • Manual rotation of the fetus from occiput posterior presentation to occiput anterior presentation can be attempted if needed in a protracted second stage.
  • An additional hour of pushing may be allowed in women with epidural anesthesia before considering operative intervention.
  • Operative vaginal delivery may be utilized when the second stage of labor is protracted. [25]
  • Differential Diagnosis
  • Abdominal Pain
  • Braxton Hicks contractions
  • Cervical stenosis
  • Placental abruption
  • Premature rupture of membranes
  • Prodromal labor
  • Uterine Mullerian anomaly
  • Uterine rupture

The prognosis of abnormal labor varies according to the stage. With a prolonged first-stage latent phase, intervention with amniotomy and oxytocin can be helpful and allow normal progression for the remainder of labor. These same strategies may be utilized with abnormalities in the active phase of the first stage of labor. A recent randomized controlled trial of early amniotomy, within 1 hour of cervical balloon catheter expulsion, shows over 2 times faster labor than waiting longer to perform amniotomy in term patients induced with mechanical cervical ripening. [26]

Maternal and neonatal morbidity is associated with a prolonged first stage of labor, including maternal fever from endometritis, shoulder dystocia, hemorrhage, and blood transfusion.  [27] [28] With an abnormal second stage of labor, oxytocin may be utilized again. An increase in third- and fourth-degree perineal lacerations, cesarean delivery, and a prolonged hospital stay is associated with a protracted or arrested second stage of labor. [29] [28]  The fetus has an increased risk of NICU admission, low Apgar scores, and a need for assisted ventilation with abnormal labor. [29]

Operative vaginal delivery may expedite the abnormal labor process in certain situations. Based on recommended criteria, cesarean delivery is indicated with abnormal labor in the first and second stages. [30]  Current methods to prevent injury, blood loss, and infection result in a good prognosis when cesarean delivery is necessitated. [22]

  • Complications

Roughly 20% of labors are associated with prolongation, protraction, or an arrest abnormality. Various adverse maternal and fetal outcomes are associated with labor abnormalities. Infection, operative birth, low Apgar score at 5 minutes, prolonged hospitalization for both mom and baby, third- and fourth-degree maternal perineal tears, above-average blood loss, and NICU (neonatal intensive care unit) admission are all increased with abnormal labor progress. [31]  

With abnormal labor being the main indication for cesarean delivery during labor, the perceived safety of the cesarean delivery must be addressed. With the increasing rate of cesarean deliveries in the United States, there has been a concomitant increase in abnormal placentation, specifically placenta accreta and placenta previa, as well as cesarean scar pregnancies. Along with these complications come a paralleled increase in maternal morbidity and mortality, as placenta accreta and placenta previa account for a large percentage of maternal morbidity and mortality. [32]

  • Deterrence and Patient Education

Educating and reassuring patients about appropriate management during labor is of utmost importance to prevent maternal and fetal morbidity and mortality resulting from prolonged, protracted, and arrested labor. Pregnant patients should be aware of possible interventions recommended during labor to prevent abnormal labor, including oxytocin augmentation, amniotomy, and manual rotation of the fetal head when appropriate. Patients are encouraged to be actively involved both in their prenatal care and their labor and delivery. Setting realistic patient expectations involves recognizing that the birthing experience is inherently unpredictable, with the primary objective being the attainment of a healthy outcome for both the mother and baby.

Staying active with regular exercise in pregnancy benefits both mother and fetus, and at least 1 randomized controlled trial showed that walking in late pregnancy may decrease the need for labor induction as well as operative vaginal delivery and cesarean section. [33] Taking steps to avoid significant weight gain in pregnancy, associated with gestational diabetes and fetal macrosomia, may help decrease the risks of abnormal labor. [34]  

Making informed decisions about the timing of labor induction can contribute to optimizing the labor process, while having a reliable support person and maintaining adequate nutrition and hydration during labor may help reduce the occurrence of abnormal labor. Dysfunctional labor can be a frightening experience for patients. Adopting a disciplined team approach to identifying and managing abnormal labor will lead to the most favorable outcomes for both the mother and baby

  • Enhancing Healthcare Team Outcomes

The appropriate management of all stages of labor is complex and, at times, challenging. The best labor management requires a coordinated interprofessional effort among trained obstetric nurses, midwives, physicians, advanced practice practitioners, anesthesiologists, the patient, their support persons, and their family. Team management may lower cesarean section rates and improve labor outcomes overall.

Labor is a dynamic process, and the care team's decision may change depending on maternal and fetal factors. Including patients in their treatment planning is mandatory. Collaboration, shared decision-making, and communication are all vital elements for a good outcome. Psychological and emotional support should be provided to patients experiencing labor abnormalities, as these women are at a higher risk of being diagnosed with postpartum depression.

Nurses, physicians, and other obstetric caregivers face challenges related to the standardization of care and the demands of productivity overload. These challenges can potentially hinder the development of strong and meaningful patient relationships, leading to increased insensitivity and burnout among healthcare providers over time. [35]  The outcome of abnormal labor depends on the stage of labor and the etiology of the abnormality. Improved outcomes require interprofessional communication and care coordination, enhancing team performance, patient-centered care, and patient safety.

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Disclosure: Prabhcharan Gill declares no relevant financial relationships with ineligible companies.

Disclosure: Joshua Henning declares no relevant financial relationships with ineligible companies.

Disclosure: Karen Carlson declares no relevant financial relationships with ineligible companies.

Disclosure: James Van Hook declares no relevant financial relationships with ineligible companies.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

  • Cite this Page Gill P, Henning JM, Carlson K, et al. Abnormal Labor. [Updated 2023 Jun 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

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RELATED TOPICS

INTRODUCTION

This topic will discuss diagnosis and management of abnormalities of the active phase of the first stage of labor. An overview of labor progress, risk factors for protraction and arrest disorders, diagnosis and management of abnormalities of the latent phase and second stage, and management of normal labor and delivery are reviewed separately:

● (See "Labor: Overview of normal and abnormal progression" .)

● (See "Labor: Diagnosis and management of the latent phase" .)

● (See "Labor: Diagnosis and management of a prolonged second stage" .)

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Obstetrics and Gynecology 7 Ed.

Abnormal labor and intrapartum fetal surveillance.

This chapter deals primarily with APGO Educational Topic Areas:

TOPIC 22  ABNORMAL LABOR

TOPIC 26  INTRAPARTUM FETAL SURVEILLANCE

Students should be able to distinguish characteristics of normal and abnormal labor using the physical examination as well as fetal monitoring and tocometry. They should understand the indications and options for operative vaginal delivery.

Clinical Case

After walking for 2 hours, your patient returns to Labor and Delivery, where she is reexamined and found to be 5 cm dilated with regular uterine contractions. She is admitted, given an epidural for pain management, and, after 6 hours, has not progressed past 6 cm dilated. How will you manage her labor at this time? What further evaluation of the patient and fetus might assist in determining the proper management of her labor?

image

Abnormal labor , or labor  dystocia  (literally, “difficult labor or childbirth”), is characterized by the abnormal progression of labor. Dystocia is the leading indication for primary cesarean delivery in the United States.  Despite the high prevalence of labor disorders, considerable variability exists in the diagnosis, management, and criteria for dystocia that requires intervention.  Because dystocia can rarely be diagnosed with certainty, the relatively imprecise term “failure to progress” has been used, which includes lack of progressive cervical dilation or lack of descent of the fetal head or both.

Factors That Contribute to Normal Labor—The Three Ps

Labor  is the occurrence of uterine contractions of sufficient intensity, frequency, and duration to bring about demonstrable effacement and dilation of the cervix. Dystocia results from what have been categorized classically as abnormalities of the “power” (uterine contractions or maternal expulsive forces), “passenger” (position, size, or presentation of the fetus), or “passage” (pelvis or soft tissues).

Uterine Contractions: “Power”

Uterine activity can be monitored by palpation, by external  tocodynamometry , or by using  intrauterine pressure catheters  [ IUPCs ] ( Fig. 9.1 ).  A tocodynamometer is an external strain gauge that is placed on the maternal abdomen. It records the frequency of uterine contractions and relaxations as well as the duration of each contraction. An IUPC, in addition to recording contraction frequency and duration, also directly measures the pressure generated by uterine contractions via a catheter inserted into the uterine cavity. The catheter is attached to a gauge that measures intrauterine pressure in mm Hg.

Recent studies suggest that the use of an IUPC instead of external tocodynamometry does not affect the outcome in cases of abnormal labor.  However, an IUPC may be useful in specific situations, such as maternal obesity and other factors that may prevent accurate clinical evaluation of uterine contractions.

For cervical dilation and fetal descent to occur, each uterine contraction must generate at least 25 mm Hg of peak pressure. Optimal intrauterine pressure is 50 to 60 mm Hg. The frequency of uterine contractions is also important in generating a normal labor pattern: the optimal frequency of uterine contractions is a minimum of three contractions in a 10-minute interval, often described as “adequate.” Uterine contractions that are too frequent are not optimal, because they prevent intervals of uterine relaxation. During this “rest interval,” the fetus receives unimpeded uteroplacental blood flow for oxygen and waste transport. Without these rest periods, fetal oxygenation may be compromised.

image

FIGURE 9.1.  Tocodynamometer and intrauterine pressure catheter.

Another unit of measure commonly used to assess contractile strength is the  Montevideo unit  ( MVU ). This unit is the number of uterine contractions in 10 minutes times the average intensity (above the resting baseline intrauterine pressure).  Normal progress of labor is usually associated with 200 or more MVU.

Fetal Factors: “Passenger”

Evaluation of the passenger includes clinical estimation of fetal weight and clinical evaluation of fetal lie, presentation, position, and attitude.  If a fetus has an estimated weight greater than 4,000 to 4,500 g, the risk of dystocia, including shoulder dystocia and fetopelvic disproportion, is greater.  Because ultrasound estimation of fetal weight is often inaccurate by as much as 500 to 1,000 g when the fetus is near term (40 weeks of gestational age), this information must be used in conjunction with other parameters when making management decisions.

Fetal attitude, presentation, and lie also play a role in the progress of labor ( Fig. 9.2 ).  If the fetal head is turned to one side ( asynclitism ) or extended ( extension ), a larger cephalic diameter is presented to the pelvis, thereby increasing the possibility of dystocia. A  brow presentation  (about 1 in 3,000 deliveries) typically converts to either a vertex or face presentation, but, if persistent, may cause dystocia requiring cesarean delivery. Likewise, a  face presentation  (about 1 in 600–1,000 deliveries) requires cesarean delivery in most cases. However, a  mentum anterior face presentation  (chin toward mother’s abdomen) may be delivered vaginally if the fetal head undergoes flexion, rather than the normal extension.  A persistent  occipitoposterior position  is also associated with longer labors (approximately 1 hour in multiparous patients and 2 hours in nulliparous patients).  In  compound presentations , when one or more limbs prolapse alongside the presenting part (about 1 in 700 deliveries), the extremity usually retracts (either spontaneously or with manual assistance) as labor continues. When it does not, or in the 15% to 20% of compound presentations associated with umbilical cord prolapse, cesarean delivery is required.

Fetal anomalies, such as hydrocephaly and soft tissue tumors, may also cause dystocia. The routine use of prenatal ultrasound for other causes has allowed identification of these situations, significantly reducing the incidence of unexpected dystocia of this kind.

Maternal Factors: “Passage”

A number of maternal factors are associated with dystocia. Dystocia can result from maternal skeletal or soft tissue anomalies that obstruct the birth canal.  Cephalopelvic disproportion , in which the size of the maternal pelvis is inadequate to the size of the presenting part of the fetus, may impede fetal descent into the birth canal.  Clinical, radiographic, and computed tomography (CT) measurements of the bony pelvis are poor predictors of successful vaginal delivery, due to the inaccuracy of these measurements as well as case-by-case differences in fetal accommodation and mechanisms of labor.

image

FIGURE 9.2.  Some of the fetal factors associated with dystocia.

Clinical pelvimetry , the manual evaluation of the diameters of the pelvis, is also a poor predictor of successful vaginal birth, except in rare circumstances when the pelvic diameters are so small as to render the pelvis “completely contracted.” Although radiographic and CT pelvimetry can be helpful in some cases, the progress of descent of the presenting part in labor is the best test of pelvic adequacy.

Soft tissue causes of dystocia include abnormalities of the cervix, tumors or other lesions of the colon or adnexa, distended bladder, uterine fibroids, an accessory uterine horn, and morbid obesity. Epidural anesthesia may contribute to dystocia by decreasing the tone of the pelvic floor musculature.

Dystocia may be associated with serious complications for both the woman and the fetus.  Infection (chorioamnionitis) is a consequence of prolonged labor, especially in the setting of ruptured membranes. Fetal infection and bacteremia, including pneumonia caused by aspiration of infected amniotic fluid, is linked to prolonged labor. In addition, there are the attendant risks of cesarean or operative delivery, such as maternal soft tissue injury to the lower genital tract and fetal trauma.

Diagnosis and Management of Abnormal Labor Patterns

Graphic documentation of progressive cervical dilation and effacement facilitates assessing a patient’s progress in labor and identifying abnormal labor patterns. The Friedman curve (see  Chapter 8 ) is commonly used for this purpose.  Labor abnormalities can be categorized into two general types:  protraction disorders , in which labor is slow to progress, and  arrest disorders , in which labor ceases to progress ( Table 9.1 ). Protraction can occur during both the latent and active phases of labor, whereas arrest is recognized only in the active phase. Although the definition of the  latent phase  of labor is controversial, in general it can be defined as the phase in which the cervix effaces but undergoes minimal dilation (see  Chapter 8 ).

image

Management of abnormal labor encompasses a wide range of options, from observation to operative or cesarean delivery.

Management choice depends on several factors:

• Adequacy of uterine contractions

• Fetal malposition or cephalopelvic disproportion

• Other clinical conditions, such as nonreassuring fetal status or chorioamnionitis

Management decisions should be balanced between ensuring a positive outcome for mother and fetus and avoiding the concomitant risks of operative and cesarean delivery.

First-Stage Disorders

A  prolonged latent phase  is one that exceeds 20 hours in a nulliparous patient or 14 hours in a multiparous patient. A prolonged latent phase does not necessarily predict an abnormal active phase of labor. Some patients who have initially been diagnosed as having a prolonged latent phase are subsequently found to have been in false labor. A prolonged latent phase does not in itself pose a danger to the mother or fetus.  Options for management of women with a prolonged latent phase of labor include observation and sedation.  With either of these options, the patient may stop having contractions, in which case she is not in labor; may go into active labor; or may continue experiencing prolonged labor into the active phase. In the latter case, other interventions as described below may be administered to augment uterine contractions.

Once the patient is in active labor, the first stage is considered prolonged when the cervix dilates less than 1 cm/hour in nulliparous women, and less than 1.2 to 1.5 cm/hour in multiparous women. Management options for a prolonged first stage include observation, augmentation by amniotomy or oxytocin, and continuous support.  Cesarean delivery is usually warranted if maternal or fetal status becomes nonreassuring.

Augmentation

Augmentation  refers to stimulation of uterine contractions when spontaneous contractions have failed to result in progressive cervical dilation or descent of the fetus. Augmentation can be achieved with  amniotomy  (artificial rupture of membranes [ROM]) and oxytocin administration.  Augmentation should be considered if the frequency of contrac-tions is less than 3 contractions per 10 minutes, the intensity of contractions is less than 25 mm Hg above the baseline, or both.  Before augmentation, the maternal pelvis and cervix as well as fetal position, station, and well-being should be assessed. If there is no evidence of disproportion and fetal well-being is reassuring, oxytocin can be used if uterine contractions are judged to be inadequate. Contraindications to augmentation are similar to those for labor induction (see  Chapter 8 ).

If the membranes have not ruptured, amniotomy may enhance progress in the active phase and negate the need for oxytocin augmentation.  Amniotomy allows the fetal head, rather than the otherwise intact amniotic sac, to be the dilating force. It may also stimulate the release of prostaglandins, which could aid in augmenting the force of contractions.

Amniotomy is usually performed with a thin, plastic rod with a sharp hook on the end. The end is guided to the open cervical os with the examiner’s fingers, and the hook is used to snag and disrupt the amniotic sac. Risks of amniotomy include fetal heart rate (FHR) decelerations due to cord compression and an increased incidence of chorioamnionitis. For these reasons, amniotomy should not be routine and should be used for women with prolonged labor. The  FHR  should be evaluated both before and immediately after ROM.

It has been shown that amniotomy combined with oxytocin administration early in the active stage reduces labor by up to 2 hours, although there is no change in the rate of cesarean delivery with this treatment protocol.  The goal of oxytocin administration is to effect uterine activity sufficient to produce cervical change and fetal descent while avoiding uterine tachysystole (defined as more than five contractions in a 10-minute period, averaged over 30 minutes). Typically, a goal of a maximum of five contractions in a 10-minute period with resultant cervical dilation is considered adequate.  Uterine activity > 200 MVUs may also be defined as adequate when utilizing an IUPC to monitor contractions.  Oxytocin may be administered in low-dose or high-dose regimens. Low-dose regimens are associated with a decreased incidence and severity of uterine hyperstimulation. High-dose regimens are associated with decreased labor times, incidence of chorioamnionitis, and cesarean delivery for dystocia.

Continuous Labor Support

Continuous support during labor from caregivers (e.g., nurses, midwives, and lay individuals) may have a number of benefits for women and their newborns. Continuous care has been associated with reduced need for pain relief and oxytocin administration, lower rates of cesarean and operative deliveries, decreased incidence of 5-minute Apgar scores lower than 7, and increased patient satisfaction with the labor experience. However, there are insufficient data comparing differences in benefits on the basis of level of training of support personnel—that is, whether the caregivers are nurses, midwives, or doulas. There is no evidence of harmful effects from continuous support during labor.

Second-Stage Disorders

A second-stage protraction disorder should be considered when the second stage exceeds 3 hours if regional anesthesia has been administered, 2 hours if no regional anesthesia is used, or if the fetus descends at a rate of less than 1 cm/hour if no regional anesthesia is used.   Second-stage arrest   is diagnosed when there is no descent after 1 hour of pushing.  In the past, the fetus was thought to be at increased risk for morbidity and mortality when the second stage exceeded 2 hours. Currently, more intensive intrapartum surveillance provides the ability to identify the fetus that may not be tolerating labor well.

Thus, the length of the second stage of labor is not in itself an absolute or even a strong indication for operative or cesarean delivery.

As long as heart tones continue to be reassuring and cephalopelvic disproportion has been ruled out, it is considered safe to allow the second stage to continue. If uterine contractions are inadequate, oxytocin administration can be initiated or the dosage increased if already in place.

Bearing-down efforts by the patient in conjunction with uterine contractions help bring about delivery. Labor positions other than the dorsal lithotomy position (e.g., knee– chest, sitting, squatting, and sitting in a birthing chair) may bring about subtle changes in fetal presentation and facilitate vaginal delivery. Fetal accommodation may also be facilitated by allowing the effects of epidural analgesia to dissipate. The absence of epidural analgesia may increase the tone of the pelvic floor muscles, thereby facilitating the cardinal movements of labor and restoring the urge to push. In some cases of fetal malpresentation, manual techniques can facilitate delivery. If the fetus is in the occipitoposterior position and does not spontaneously convert to the normal position, rotation can be performed to turn the fetus to the anterior position ( Fig. 9.3 ).

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FIGURE 9.3.  Manual rotation of a fetus in the occipitoposterior position to the occipitoanterior position.  (A)  The physician’s hand is placed palm upward into the vagina.  (B)  The hand serves as a wedge to flex the fetal head while the fingers exert a rotating force to bring the occiput to anterior. AF, anterior fontanel. (Adapted from Shields SG, Ratcliffe SD, Fontain P, Leeman L. Dystocia in nulliparous women.  Am Fam Physician . 2007;75(11):1675.)

The decision to perform an operative delivery in the second stage versus continued observation should be made on the basis of clinical assessment of the woman and the fetus and the skill and training of the obstetrician. Nonreassuring status of the fetus or mother is an indication for operative or cesarean delivery.

Operative vaginal deliveries are accomplished by applying direct traction on the fetal skull with forceps or by applying traction to the fetal scalp by means of a vacuum extractor. The incidence of operative vaginal delivery in the United States is estimated to be 10% to 15%.  Although considered safe in appropriate circumstances, operative vaginal delivery has the potential for maternal and neonatal complications.  Operative vaginal delivery should be performed only by individuals with privileges for such procedures and in settings in which personnel are readily available to perform a cesarean delivery in the event the operative vaginal delivery is unsuccessful. However, the incidence of intracranial hemorrhage is highest among infants delivered by cesarean delivery following a failed vacuum or forceps delivery. The combination of vacuum and forceps has a similar risk of intracranial hemorrhage. Therefore, an operative vaginal delivery should not be attempted when the probability of success is very low.

Classification

For both forceps and vacuum extraction deliveries, the type of delivery depends on the fetal station—the relationship between the leading portion of the fetal head and the level of the maternal ischial spines.  Outlet operative vaginal delivery  is the application of forceps or vacuum under the following conditions:

1.  The scalp is visible at the introitus without separating labia.  2.  The fetal skull has reached pelvic floor.

3.  The sagittal suture is in anteroposterior diameter or right or left occiput anterior or posterior position.

4.  The fetal head is at or on the perineum.

5.  Rotation does not exceed 45°.

Low operative vaginal delivery  is the application of forceps or vacuum when the leading point of the fetal skull is at station +2 or more and is not on the pelvic floor. This type of operative vaginal delivery has two subtypes:

1.  Rotation of 45° or less (left or right occiput anterior to occiput anterior, or left or right occiput posterior to occiput posterior)

2.  Rotation greater than 45°

Midpelvis operative vaginal delivery  is the application of forceps or vacuum when the fetal head is engaged but the leading point of the skull is above station +2. Under very unusual circumstances, such as the sudden onset of severe fetal or maternal compromise, application of forceps or vacuum above station +2 may be attempted while simultaneously initiating preparation for a cesarean delivery in the event that the operative vaginal delivery is unsuccessful.

Indications and Contraindications

No indication for operative vaginal delivery is absolute. The following indications apply when the fetal head is engaged and the cervix is fully dilated:

• Prolonged or arrested second stage of labor

• Suspicion of immediate or potential fetal compromise

• Shortening of the second stage for maternal benefit

In certain situations, operative vaginal delivery should be avoided or, at the least, carefully considered in terms of relative maternal and fetal risks. Most authorities consider vacuum extraction inappropriate in pregnancies before 34 weeks of gestation because of the risk of fetal intraventricular hemorrhage.  Operative delivery is also contraindicated if a live fetus is known to have a bone demineralization condition (e.g., osteogenesis imperfecta) or a bleeding disorder (e.g., alloimmune thrombocytopenia, hemophilia, and von Willebrand disease), and if the fetal head is unengaged or the position of the fetal head is unknown.

Forceps  are primarily used to apply traction to the fetal head to augment the expulsive forces, when the mother’s voluntary efforts in conjunction with uterine contractions are insufficient to deliver the infant ( Fig. 9.4 ). Occasionally, forceps are used to rotate the fetal head before applying traction to complete vaginal delivery. Forceps may also be used to control delivery of the fetal head, thereby avoiding precipitous delivery. Different types of forceps are available for the different degrees of molding of the fetal head.

Maternal complications of forceps delivery include perineal trauma, hematoma, and pelvic floor injury. Neonatal risks include injuries to the brain and spine, musculoskeletal injury, and corneal abrasion if the forceps are mistakenly applied over the neonate’s eyes. The risk of  shoulder dystocia , in which the fetus’s anterior shoulder becomes lodged against the pubic symphysis, is increased in forceps deliveries of infants weighing over 4,000 g.

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FIGURE 9.4.  Forceps delivery. (Adapted from Bofill JA.  Forceps in Obstetrics  [Slide presentation]. Washington, DC: American College of Obstetricians and Gynecologists; 2001.)

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FIGURE 9.5.  Vacuum extractor. Because the vacuum port can be bent at a 90° angle to the cup, it is useful in malpositions of the fetal head. (Adapted from Bofill JA.  Safe Vacuum Delivery  [Slide presentation]. Washington, DC: American College of Obstetricians and Gynecologists; 2001.)

Vacuum Extraction

In  vacuum extraction , a soft vacuum cup is applied to the fetal head and suction is exerted by means of a mechanical pump ( Fig. 9.5 ). Vacuum extraction is associated with less maternal trauma than forceps but carries significant potential neonatal risks. Although the amount of traction applied to the fetal skull is less than that applied with forceps, it is still substantial and can cause serious fetal injury. Neonatal risks include intracranial hemorrhage, subgaleal hematomas, scalp lacerations (if torsion is excessive), hyperbilirubinemia, and retinal hemorrhage. In addition, separation of the scalp from the underlying structures can lead to cephalohematoma.  Overall, the incidence of serious complications with vacuum extraction is approximately 5%.  It is recommended that rocking movements or torque should not be applied to the device and that only steady traction in the line of the birth canal should be used. Clinicians caring for the neonate should also be alerted that an operative delivery has been used so that they can monitor the neonate for signs and symptoms of injury.

Breech presentation  occurs in about 2% of singleton deliveries at term and more frequently in the early third and second trimesters. In addition to prematurity, other conditions associated with breech presentation include multiple pregnancy, polyhydramnios, hydrocephaly, anencephaly, aneuploidy, uterine anomalies, and uterine tumors. The three kinds of breech presentation— frank, complete,  and  incomplete  ( footling )  breech  ( Fig. 9.6 )—are diagnosed by a combination of Leopold maneuvers, pelvic examination, ultrasonography, and other imaging techniques ( Fig. 9.7 ).  The morbidity and mortality rates for mother and fetus, regardless of gesta-tional age or mode of delivery, are higher in the breech than in the cephalic presentation.  This increased risk to the fetus comes from associated factors such as fetal anomalies, prematurity, and umbilical cord prolapse as well as birth trauma.

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FIGURE 9.6.  Types of breech presentations.  (A)  Frank breech, in which the feet are near the head;  (B)  complete breech, in which the legs are crossed;  (C)  incomplete (footling) breech, in which one or both feet are extended.

External cephalic version  ( ECV ) involves applying pressure to the mother’s abdomen to turn the fetus in either a forward or backward somersault to achieve a vertex presentation prior to labor ( Fig. 9.8 ). The goal of ECV is to increase the proportion of vertex presentations among fetuses that were formerly in the breech position near term. Once a vertex presentation is achieved, the chances for a vaginal delivery increase.  This maneuver is successful in approximately half of the properly selected cases.  Patients who have completed 36 weeks of gestation are preferred candidates for ECV for several reasons. First, if spontaneous version is going to occur, it is likely to have taken place by 36 completed weeks of gestation. Second, the risk of a spontaneous reversion is decreased after ECV at term compared with earlier gestations.  Selection criteria include a normal fetus with reassuring fetal heart tracing, adequate amniotic fluid, and presenting part not in the pelvis.  The risks include premature ROM, placental abruption, cord accident, and uterine rupture. External version is more often successful in parous women.  Existing evidence may support the use of a tocolytic agent (i.e., a drug that stops uterine contractions) during ECV attempts, particularly in nulliparous patients.  Administration of anti-D immunoglobulin to Rh-negative women is recommended.

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FIGURE 9.7.  Leopold maneuvers. The maneuvers are used to determine fetal position: 1) determination of what is in the fundus; 2) evaluation of the fetal back and extremities; 3) palpation of the presenting part above the symphysis; and 4) determination of the direction and degree of flexion of the head.

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FIGURE 9.8.  External cephalic version. In this maneuver, the fetus is converted from a breech to a vertex presentation.

In light of recent studies that further clarify the long-term risks of vaginal breech delivery, the decision regarding the mode of delivery should depend on the experience of the health care provider.  Cesarean delivery will be the preferred mode for most physicians because of the diminishing expertise in vaginal breech delivery.  Planned vaginal delivery of a term singleton breech fetus may be reasonable under hospital-specific protocol guidelines for both eligibility and labor management. The following criteria have been suggested for vaginal breech delivery:

• Normal labor curve

• Gestational age greater than 37 weeks

• Frank or complete breech presentation (because of the risk of umbilical cord prolapse, vaginal delivery of a fetus in the footling breech position is not recommended)

• Absence of fetal anomalies on ultrasound examination

• Adequate maternal pelvis

• Estimated fetal weight between 2,500 and 4,000 g

• Documentation of fetal head flexion (hyperextension of the fetal head occurs in about 5% of term breech fetuses, requiring cesarean delivery to avoid head entrapment)

• Adequate amniotic fluid volume (defined as a 3-cm vertical pocket)

• Availability of anesthesia and neonatal support

If a vaginal breech delivery is planned, the woman should be informed that the risk of perinatal or neonatal mortality or short-term serious neonatal morbidity may be higher than in a cesarean delivery, and the patient’s informed consent should be documented.

Shoulder dystocia may sometimes arrest expulsion. Shoulder dystocia cannot be predicted or prevented, because accurate methods for identifying which fetuses will experience this complication do not exist. Antepartum conditions associated with shoulder dystocia include multiparity, postterm gestation, previous history of a macrosomic birth, and a previous history of shoulder dystocia. Although fetal macrosomia increases the risk of shoulder dystocia, elective induction of labor or elective cesarean delivery for all women suspected of carrying a fetus with macrosomia is not appropriate.

Diagnosis of shoulder dystocia has a subjective component, especially in less severe forms. The delivered fetal head may retract against the maternal perineum ( turtle sign ) and, if so, may assist in the diagnosis. Interventions that may be used to facilitate delivery include the  McRoberts maneuver  (hyperflexion of the mother’s legs tight to the abdomen) and the application of suprapubic pressure to assist in dislodging the impacted shoulder ( Fig. 9.9 ). In contrast, fundal pressure may further worsen impaction of the shoulder and may also result in uterine rupture. Controversy exists as to whether episiotomy is necessary, because shoulder dystocia is typically not caused by obstructing soft tissue. Direct fetal manipulation with either rotational maneuvers or delivery of the posterior arm may also be used. In severe cases, more aggressive interventions, such as the  Zavanelli maneuver  (in which the fetal head is flexed and reinserted into the vagina to reestablish umbilical cord blood flow and delivery performed through cesarean section) and intentional fracture of the fetal clavicle, may be performed. Regardless of the procedures used, brachial plexus injury is associated with shoulder dystocia; incidence ranges from 4% to 40%. However, most cases resolve without permanent disability.  Fewer than 10% of all cases of shoulder dystocia result in a persistent brachial plexus injury.

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FIGURE 9.9.  Procedures used to relieve shoulder dystocia.  (A)  McRoberts maneuver. Hyperflexion and abduction of the hips cause cephalad rotation of the symphysis pubis and flattening of the lumbar lordosis that frees the impacted shoulder.  (B)  Suprapubic pressure directed downward on the anterior shoulder and laterally toward the baby’s sternum.

Evidence suggesting a  nonreassuring fetal status  during labor occurs in 5% to 10% of pregnancies.  Intrapartum fetal surveillance  is the indirect measurement of indicators of fetal status, such as FHR, blood gases, pulse rate, amniotic fluid volume, and fetal stimulation responses, during labor.  The goal of intrapartum fetal surveillance is to recognize changes in fetal oxygenation that could result in serious complications.  However, it is now recognized that many neurologic conditions previously attributed to  birth asphyxia  (defined as a situation of damaging acidemia, hypoxia, and metabolic acidosis) are in fact attributable to other causes not associated with labor, such as maternal infection, coagulation disorders, and autoimmune disorders; genetic causes; and low birthweight.  Intrapartum fetal surveillance is a tool for detection of events that occur during labor that could compromise fetal oxygenation and, in rare cases, lead to permanent neurologic disability.

Pathophysiology

The  uteroplacental unit  provides oxygen and nutrients to the fetus while receiving carbon dioxide and wastes, the products of the normal aerobic fetal metabolism.  Uteroplacental insufficiency  occurs when the uteroplacental unit is compromised. Initial fetal responses include fetal hypoxia (decreased blood oxygen levels); shunting of blood flow to the fetal brain, heart, and adrenal glands; and transient, repetitive, late decelerations of the FHR. If hypoxia continues, the fetus will eventually switch over to anaerobic glycolysis and develop metabolic acidosis. Lactic acid accumulates, and progressive damage to vital organs occurs, especially the fetal brain and myocardium. If intervention is not timely, serious and possibly permanent damage and sometimes death can result.

Neonatal Encephalopathy

Neonatal encephalopathy  is a clinically defined syndrome of disturbed neurologic function in the earliest days of life in the term infant, manifested by difficulty with initiating and maintaining respiration, depression of tone and reflexes, subnormal level of consciousness, and sometimes seizures. Neonatal encephalopathy is not always associated with permanent neonatal neurologic impairment.  Hypoxic-ischemic encephalopathy  ( HIE ) is a subtype of neonatal encephalopathy for which the cause is considered to be the limitation of oxygen and blood flow near the time of birth. Historically, it has been assumed that most cases of neonatal encephalopathy were HIE, but epidemiologic studies have established that this assumption is incorrect.

Approximately 70% of cases of neonatal encephalopathy are caused by factors that were present before the onset of labor.  It is estimated that the incidence of neonatal encephalopathy caused by intrapartum hypoxia is approximately 1.6/10,000, in the absence of any other coincident preconceptual or antepartum abnormalities. HIE is, thus, one among the larger category of encephalopathies that may result from conditions such as prenatal stroke, prenatal infection, genetic abnormalities, and neonatal cerebral malformation. The criteria sufficient to suggest that an encephalopathy is associated with an acute intrapartum event are presented in  Box 9.1 .

BOX 9.1   Criteria to Define an Acute Intrapartum Hypoxic Event as Sufficient to Cause Cerebral Palsy

I. Essential criteria (must meet all four)

a. Fetal metabolic acidosis demonstrated from umbilical cord arterial blood gas measurement (pH < 7 and base deficit ≥12 mmol/L)

b. Early-onset severe or moderate neonatal encephalopathy in newborn of ≥34 weeks of gestational age

c. Spastic or, less commonly, dyskinetic cerebral palsy d. Exclusion of other identifiable causes (trauma, coagulopathy, infection, or genetic anomaly)

II. Criteria nonspecific to asphyxial insult, but suggestive of intrapartum timing (close proximity to labor and delivery, within 48 hours)

a. Sentinel hypoxic event immediately before or during labor

b. Sudden nonreassuring fetal heart rate pattern (e.g., sudden, sustained fetal bradycardia or absent variability in the presence of persistent late or variable decelerations)

c. Apgar scores of 0 to 3 beyond 5 minutes

d. Onset of multisystem illness (e.g., acute bowel injury, renal failure, hepatic failure, cardiac damage, and hematologic abnormalities) within 72 hours of birth e. Early cerebral imaging with evidence of acute nonfocal cerebral abnormality

From ACOG Task Force on Neonatal Encephalopathy and Cerebral Palsy.  Neonatal Encephalopathy and Cerebral Palsy: Defining the Pathogenesis and Pathophysiology.  Washington, DC: American College of Obstetricians and Gynecologists; 2003:74.

Cerebral Palsy

Cerebral palsy  is a chronic disability of the central nervous system (CNS) characterized by aberrant control of movement and posture appearing early in life and not as a result of progressive neurologic disease. Only one type of cerebral palsy,  spastic quadriplegia , is associated with antepartum or intrapartum interruption of the fetal blood supply. Disorders not associated with intrapartum or peripartum asphyxia include dyskinetic or ataxic cerebral palsy (which commonly has a genetic origin) and epilepsy, mental retardation, or attention-deficit hyperactivity disorders.

Intrapartum Fetal Heart Rate Monitoring

FHR monitoring  is a modality intended to determine if a fetus is well oxygenated. The majority of neonates (approximately 85%) born in the United States are assessed with  electronic fetal monitoring ( EFM ), making it the most common obstetric procedure.  Intermittent auscultation  of the FHR after a contraction is also used to assess intrapartum fetal well-being. Beginning in the 1980s, EFM became more common; the rates of its use have doubled over the past 35 years.

EFM may be performed externally or internally. Most external monitors use a Doppler device with computerized logic to interpret and count the Doppler signals. Internal FHR monitoring is accomplished with a fetal electrode, which is a spiral wire placed directly on the fetal scalp or other presenting part.

FHRs by EFM are described in terms of baseline rate, variability, presence of accelerations, periodic or episodic decelerations, and the changes in these characteristics over time ( Table 9.2 ) and classified by a three-tier FHR interpretation system ( Box 9.2 ).  The goal of FHR monitoring is to detect signs of fetal jeopardy in time to intervene before irreversible damage occurs.  Despite the liberal use of continuous EFM in both high-risk and low-risk patients, there has been no consistent decrease in the frequency of cerebral palsy in the last two decades. Fetuses who are severely asphyxiated during the intrapartum period will have abnormal heart rate patterns.  However, most patients with nonreassuring FHR patterns give birth to healthy infants. In addition, the false-positive rate of EFM for predicting adverse outcomes is high.  Guidelines for intrapartum FHR monitoring are given in  Table 9.3 .

Fetal Heart Rate Patterns

The normal baseline FHR is 110 to 160 beats per minute (bpm). An FHR less than 110 bpm is considered  bradycardia . Fetal bradycardia between 100 and 110 bpm can usually be tolerated for long periods when it is accompanied by normal FHR variability. An FHR between 80 and 100 bpm is nonreassuring. An FHR that persists below 80 bpm is an ominous sign and may presage fetal death.

An FHR above 160 bpm is considered  tachycardia . The most common cause of fetal tachycardia is chorioamnionitis, but it may also be due to maternal fever, thyrotoxicosis, medication, and fetal cardiac arrhythmias. Fetal tachycardia between 160 and 200 bpm without any other abnormalities in FHR is usually well tolerated when accompanied by normal FHR variability.

Fetal Heart Rate Variability

FHR variability  refers to the fluctuations in the FHR of two cycles or more, visually quantified as the amplitude of peak to trough in bpm. FHR is graded according to amplitude range ( Fig. 9.10 ; also see  Table 9.2 ).  Moderate variability is a reassuring sign that reflects adequate fetal oxygenation and normal brain function. In the presence of normal FHR variability, regardless of what other FHR patterns exist, the fetus is not experiencing cerebral tissue asphyxia.

Decreased variability is associated with fetal hypoxia, acidemia, drugs that may depress the fetal CNS (e.g., maternal narcotic analgesia), fetal tachycardia, fetal CNS and cardiac anomalies, prolonged uterine contractions (uterine hypertonus), prematurity, and fetal sleep.

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BOX 9.2   Three-Tier Fetal Heart Rate Interpretation System

Category I fetal heart rate (FHR) tracings include  all  of the following:

• Baseline rate: 110 to 160 bpm

• Baseline FHR variability: moderate

• Late or variable decelerations: absent

• Early decelerations: present or absent

• Accelerations: present or absent

CATEGORY II

Category II FHR tracings include all FHR tracings not categorized as category I or category III. Category II tracings may represent an appreciable fraction of those encountered in clinical care. Examples of category II FHR tracings include any of the following:

Baseline Rate

• Bradycardia not accompanied by absent baseline variability

• Tachycardia

Baseline FHR Variability

• Minimal baseline variability

• Absent baseline variability not accompanied by recurrent decelerations

• Marked baseline variability

Accelerations

• Absence of induced accelerations after fetal stimulation

Periodic or Episodic Decelerations

• Recurrent variable decelerations accompanied by minimal or moderate baseline variability

• Prolonged deceleration ≥2 minutes but <10 minutes

• Recurrent late decelerations with moderate baseline variability

• Variable decelerations with other characteristics, such as slow return to baseline, “overshoots,” and “shoulders”

CATEGORY III

Category III FHR tracings include either:

• Absent baseline FHR variability and any of the following:

– Recurrent late decelerations

– Recurrent variable decelerations

– Bradycardia

• Sinusoidal pattern

From Macones GA, Hankins GDV, Spong CY, Hauth J, Moore T. The 2008 National Institute of Child Health and Human Development Workshop Report on Electronic Fetal Monitoring: Update on Definitions, Interpretation and Research Guidelines.  Obstet Gynecol.  September 2008;112(3):661–666.

Periodic Fetal Heart Rate Changes

The FHR may vary with uterine contractions by slowing or accelerating in periodic patterns. These  periodic FHR changes  are classified as accelerations or decelerations, based on whether they increase or decrease in the FHR and on their magnitude (in bpm).

Accelerations  of the FHR are visually apparent increases (onset to peak in less than 30 seconds) in the FHR from the most recently calculated baseline (see  Table 9.2 ).  Accelerations are generally associated with reassuring fetal status and an absence of hypoxia and acidemia. Stimulation of the fetal scalp by digital examination usually causes heart rate acceleration in the normal fetus with an arterial fetal pH > 7.20 if delivery were to occur at the time of measurement. For this reason, fetal scalp stimulation is sometimes used as a test of fetal well-being. External vibration stimulation, also termed  vibroacoustic stimulation , elicits the same response and is also used for this purpose (see Section “Ancillary Tests”).

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FIGURE 9.10.  Fetal heart rate (FHR) variability. bpm, beats per minute.

Decelerations

FHR  decelerations  are visually apparent decreases in FHR from the baseline.  They can be either gradual (onset to nadir in 30 seconds or more) or abrupt (onset to nadir in less than 30 seconds).  Early decelerations  are associated with uterine contractions: the nadir of the deceleration occurs at the same time as the peak of the uterine contraction and, thus, is a “mirror image” of the contraction ( Fig. 9.11 ). Early decelerations are the result of pressure on the fetal head from the birth canal, digital examination, or forceps application that causes a reflex response through the vagus nerve with acetylcholine release at the fetal sinoatrial node. This response may be blocked with vagolytic drugs such as atropine. Early FHR decelerations are considered physiologic and are not a cause of concern.

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FIGURE 9.11.  Fetal heart rate (FHR) patterns.  (A)  Early deceleration. Notice how the nadir of the deceleration occurs at the same time as the peak of the uterine contraction; they are mirror images of each other.  (B)  Variable deceleration. These decelerations may start before, during, or after a uterine contraction starts.  (C)  Late deceleration. The onset, nadir, and recovery of the deceleration occur, respectively, after the beginning, peak, and end of the contraction.

Late FHR decelerations  are visually apparent decreases in the FHR from the baseline FHR, associated with uterine contractions. The onset, nadir, and recovery of the deceleration occur, respectively, after the beginning, peak, and end of the contraction.  Late decelerations are considered significantly nonreassuring, especially when repetitive and associated with decreased variability.  Repetitive late decelerations are defined as occurring after 50% or more of contractions in a 20-minute period. Late decelerations are associated with uteroplacental insufficiency, as a result of either decreased uterine perfusion or decreased placental function, and, thus, with decreased intervillous exchange of oxygen and carbon dioxide and progressive fetal hypoxia and acidemia.

Variable FHR decelerations  are abrupt, visually apparent decreases in the FHR below the baseline FHR.  These variable decelerations may start before, during, or after uterine contraction starts, hence the term “variable.” Variable decelerations are also mediated through the vagus nerve, with sudden and often erratic release of acetylcholine at the fetal sinoatrial node, resulting in their characteristic sharp deceleration slope. They are usually associated with umbilical cord compression, which may result from wrapping of the cord around parts of the fetus, fetal anomalies, or even knots in the umbilical cord. They are also commonly associated with oligohydramnios, in which the buffering space for the umbilical cord created by the amniotic fluid is lost.  Variable decelerations are the most common periodic FHR pattern.  They are often correctable by changes in the maternal position to relieve pressure on the umbilical cord. Infusion of fluid into the amniotic cavity ( amnioinfusion ) to relieve umbilical cord compression in cases of oligohydramnios or when ROM has occurred has been shown to be effective in decreasing the rate of decelerations and cesarean delivery.

Ancillary Tests

Because the rate of false-positive diagnosis of EFM is high, attempts have been made to find ancillary tests that help confirm a nonreassuring FHR tracing.

Fetal Stimulation

In the case of an EFM tracing with decreased or absent variability without spontaneous accelerations, an effort should be made to elicit one.  Four techniques are available to stimulate the fetus: 1) fetal scalp sampling, 2) Allis clamp scalp stimulation, 3) digital scalp stimulation, and 4) vibroacoustic stimulation. Each of the first three techniques involves accessing the fetal scalp through the dilated cervix. In vibroacoustic stimulation, the fetus is stimulated when the device is placed on the maternal abdomen over the area of the fetal head. In digital scalp stimulation, the physician uses his or her finger to gently stroke the scalp.

Each of these tests is a reliable method to exclude acidosis if accelerations are noted after stimulation. Because vibroacoustic stimulation and scalp stimulation are less invasive than the other two methods, they are the preferred methods. When there is an acceleration following stimulation, acidosis is unlikely and labor can continue.

Determination of Fetal Blood pH or Lactate

When a nonreassuring FHR tracing persists without spontaneous or stimulated accelerations, a scalp blood sample for the determination of pH or lactate can be considered ( Fig. 9.12 ). However, the use of scalp pH has decreased, and it may not be available at some tertiary hospitals. Furthermore, the positive predictive value of a low scalp pH to identify a newborn with HIE is only 3%.

Pulse Oximetry

The use of pulse oximetry has been suggested as a modality to reduce the false-positive diagnosis of a nonreassuring FHR. However, research has demonstrated that neither the overall rate of cesarean delivery nor the rate of umbilical arterial pH less than 7 decreased when pulse oximetry was used in association with EFM in cases of nonreassuring fetal status.  Because of the uncertain benefit of pulse oximetry and concerns about falsely reassuring fetal oxygenation, use of the fetal pulse oximeter in clinical practice cannot be supported at this time.

image

FIGURE 9.12.  Fetal scalp sampling.

Diagnosis and Management of a Persistently Nonreassuring Fetal Heart Rate Pattern

A reassuring FHR pattern (category I) may include a normal baseline rate, moderate FHR variability, persistence of accelerations, and absence of decelerations. Patterns believed to be predictive of current or impending fetal asphyxia (category III) include absence of FHR variability and recurrent late decelerations, recurrent severe variable decelerations, and sustained bradycardia. An indeterminant FHR pattern (category II) is one that falls between these two extremes.

In the presence of an indeterminate (category II) or nonreassuring (category III) FHR pattern, the etiology should be determined, if possible, and an attempt should be made to correct the pattern by addressing the primary problem. If the pattern persists, initial measures include placing the patient in the left lateral position, administering oxygen, correcting maternal hypotension, and discontinuing oxytocin, if appropriate. Where the pattern does not respond to change in position or oxygenation, the use of tocolytic agents has been suggested to abolish uterine contractions and prevent umbilical cord compression. Uterine tachysystole can be identified by evaluating uterine contraction frequency and duration and can be treated with β-adrenergic drugs. Amnioinfusion may also be used to prevent umbilical cord compressions.  Awaiting vaginal delivery is appropriate if it has been determined that delivery is imminent. If it is not, and there is evidence of progressive fetal hypoxia and acidosis, cesarean delivery is warranted.

Meconium  is a thick, black, tarry substance that is present in the fetal intestinal tract. It is composed of amniotic fluid,  lanugo  (the fine hair that covers the fetus), bile, and fetal skin and intestinal cells. The neonate’s first stool consists of meconium. However, the fetus may pass the meconium in utero, which is a sign of fetal stress. Meconium passage is detected during labor when the amniotic fluid is stained dark green or black.  Meconium-stained amniotic fluid is present in about 10% to 20% of births, and most meconium-stained neonates do not develop problems.

Meconium aspiration syndrome , a condition caused by inhalation of meconium-stained amniotic fluid by the fetus, occurs in about 6% of births in which meconium is present. Severe cases of this syndrome may cause pneumonitis, pneumothorax, and pulmonary artery hypertension.

When there is thick meconium at delivery, interventions to prevent or decrease meconium aspiration syndrome should be considered.  Because meconium passage may predate labor, amnioinfusion should not be used as a preventive measure for   meconium aspiration syndrome.  Suctioning of the upper airway on the perineum does not prevent or alter the course of meconium aspiration syndrome. If the infant is not vigorous and thick meconium is present, the fetus should be intubated and suctioning to remove material below the glottis should be performed before initiating positive pressure ventilation. If the infant is active, suctioning and intubation are therapeutic options that are part of ongoing stabilization and care; however, they are likely unnecessary in the vigorous infant.

Clinical Follow-Up

The fetal heart rate is a category I, and your patient previously delivered an 8-lb infant vaginally. You decide to artificially rupture her membranes, and, if her contractions do not subsequently become adequate, you plan to augment her labor with oxytocin. You evaluate the estimated fetal weight and position of the fetal vertex in the pelvis prior to augmenting her labor.

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Basic Knowledge

educational topic 22 abnormal labor

Abnormal Labor

Duration = 11:23

Epico educational topic number 22

abnormal labor you may remember our

patient labora deliver it from our app

go video number eleven intrapartum care

we follow libera through a normal labor

and delivery course in that video in

this video labora will experience

abnormal labor we will discuss how best

to provide care for labora and her fetus

to optimize outcomes the objectives of

this video are to list and describe the

causes and methods of evaluation of

abnormal labor patterns discuss fetal

and maternal complications of abnormal

labor list indications and

contraindications for oxytocin

administration describe risks and

benefits of trials of labor after

caesarean delivery and lastly discuss

strategies for emergency management of

breech presentation

shoulder dystocia and cord prolapse here

is labora entering labor and delivery

and active labor

she is dilated to 5 centimeters let’s

start by talking about the 3 p’s that

contribute to a normal labor the power

the passenger and the passage the power

refers to uterine contractions the

uterus must produce strong frequent

contractions that will dilate the cervix

and cause the fetus to descend down

ideally the uterus should contract three

times in a 10-minute period here is a

fetal heart rate tracing and remember

that the top line is the fetal heart

rate and the bottom line are the uterine

contractions this tracing shows ten

minutes of laborious labor and she has

three contractions marked by the white

arrows the uterine contractions are

usually monitored by an external tool

commoner which does not give information

about the strength of the contractions

just the timing let’s check back on

labora she was admitted to labor and

delivery in active labor at five

centimeters dilated and she’s been

having regular painful contractions for

two hours since she is a gravity’ one

pair zero and active labor her cervix is

expected to dilate at approximately one

point two centimeters per hour a

multi-purpose patient and active labour

should have progression of approximately

1.5 centimeters per hour after 2 hours

when we recheck labora cervix it is

unchanged and it is still 5 centimeters

in order to assess the strength of the

contractions we place an intrauterine

pressure catheter or IUP see this

tracing is from an IUP see the strength

of the contraction is the amplitude of

each wave a Montevideo unit

can be simply calculated by measuring

the amplitude above the baseline for a

10-minute period and adding them

normal labor progress is usually

associated with a Montevideo unit of

greater than 200 next let’s move on to

the passenger ideally the foetus is not

too big and is in a good position for

delivery if the fetus has an estimated

weight greater than 4,500 grams the risk

of shoulder dystocia and labour dystocia

are greater the fetal position is

important as well for ideally you want

the fetus positioned in the optimal way

to be able to fit through the pelvis

let’s review the bony landmarks of the

fetal vertex on vaginal examination the

diamond-shaped anterior fontanelle and

the triangular shape posterior

fontanelle can be palpated as well as

the sagittal suture this photo has a

better view of the triangular shaped

posterior fontanelle we describe the

fetal position in relationship to the

fetal occiput and the maternal body here

is a fetus in the occiput anterior

position here is the posterior

fontanelle and the occupant is on the

anterior part of the maternal body this

is the optimal position for delivery for

this as the smallest diameter that has

to pass through the pelvis this fetus is

in the occiput posterior position note

the posterior occiput and the anterior

fontanelle this fetus is in the occiput

transverse position both the occiput

posterior and occiput transverse

positions have bigger diameters that

need to fit through the pelvis there are

other possible presentations such as a

compound presentation or face

presentation which could all contribute

to labor dystocia labor can be stalled

before she reaches ten centimeters

dilated known as failure to progress or

arrest and dilation where the patient

can reach ten centimeters and the fetus

does not descend for delivery known as a

rest of descent the last of the three

P’s to discuss is passage maternal

skeletal or soft tissue issues can

obstruct the birth canal

cephalo pelvic disproportion refers to

the conflict between the fetal head and

the pelvic size the pelvic bone shape or

maternal soft tissue most commonly

excess adipose tissue can contribute to

labor dystocia let’s get back to labora

remember that she was admitted at five

centimeters dilated in active labor at

the time of a repeat sterile vaginal

examination she was still 5 centimeters

and replaced an intrauterine pressure

catheter and this demonstrated that her

contractions were not strong enough

augmentation refers to stimulation of

uterine contractions amniotic or

rupturing of her amniotic membranes can

enhance progress in the active phase it

may stimulate release of prostaglandins

which aid in augmenting the force of

contractions and also allows for the

fetal head to be the dilating force

oxytocin can also be given intravenously

to strengthen contractions the goal is

to titrate the oxytocin so that the

contractions are strong and frequent

enough to produce cervical change in

fetal descent but not too strong to

cause uterine tachy systole uterine

tachy systole is defined as more than

five contractions in 10 minutes over a

30 minute period you perform an an Reata

me and oxytocin has started for labora

three hours later you check on her and

she is happily 10 centimeters dilated

and she starts pushing her second stage

is slow but she continues to make

progress and after 2.5 hours of pushing

she delivers the fetal head and you

realize that the anterior shoulder is

stuck this is a shoulder dystocia let’s

now switch gears to discuss shoulder

shoulder dystocia can be a true

obstetric ‘el emergency the baby’s

anterior shoulder is effectively caught

behind the pubic symphysis which is

illustrated in white it is important to

remain calm and to know the steps to

help deliver the shoulder in general

there is about 5 minutes to deliver a

well oxygenated term infant first and

foremost take steps to make sure that

you have adequate nursing and obstetric

‘el staff support start with McRoberts

maneuver which is hyper flexion and

abduction of the hips this can open up

space that will enable the shoulder to

be reduced the next step is suprapubic

pressure which is pressure directed

downward on the anterior shoulder if

these first two steps do not lead to

delivery then next try to deliver the

posterior arm of the fetus an episiotomy

can be helpful at this point to open up

space posteriorly additional steps for

shoulder dystocia include the wood screw

and Reuben maneuver which are rotation

of the fetus to reduce the shoulder it

can also be helpful to move the patient

onto her hands and knees in severe cases

intentional clavicular fracture can be

performed and the last option is to

perform as a Vannelli

procedure which requires reversing the

Cardinal movements to labor and to flex

the head back into the uterus and to

perform a cesarean delivery brachial

plexus injury rates with a shoulder

dystocia range from four to forty

percent regardless of the maneuvers used

to deliver the fetus the second

obstetrical emergency that we will now

discuss is cord prolapse this is when

the umbilical cord descends in advance

of the fetal presenting part here is the

fetus and the blue umbilical cord that

has prolapsed through the cervix cord

prolapse occurs when one the fetus is

not vertex or two there are spontaneous

rupture of membranes before the vertex

is well engaged or three there is

iatrogenic artificial rupture of

membranes before the vertex is well

engaged cord prolapse is an emergency

for the blood vessels in the umbilical

cord are compressed when this is

recognized the providers hand must push

the fetal head up so it does not further

compress the cord and the cord needs to

be manually reduced back into the

uterine cavity and the patient needs to

be brought back to the operating room

for an immediate caesarean section the

hand needs to stay in place throughout

this time until the baby is safely

delivered the last emergency that we

will discuss is breech delivery it is

important to note that singleton breech

presentations should be delivered by

cesarean section there may be situations

however when cesarean section is not

possible because of precipitous delivery

or lack of operative resources if this

situation were to arise the first thing

is to call for assistance next it’s

important to avoid any traction on the

fetus for the goal is to avoid a fetal

head extension which can make the

delivery more difficult wait until the

maternal efforts have resulted in the

fetus being delivered to the level of

the umbilicus suprapubic pressure can

then be applied to promote flexion and

descent of the fetal head we will

conclude laborious journey into the

world of abnormal labor with a

discussion about women who have had a

previous cesarean section what if labore

had a history with cesarean section with

their first pregnancy there are three

primary possible outcomes she could have

a successful trial of labor after

cesarean which is a vaginal birth after

cesarean or VBAC this is the ideal

option for labora will have decreased

maternal morbidity and decreased risk of

complications with future pregnancies at

a population level more vivax mean there

is a decreased overall cesarean delivery

our next preferred option would be a

scheduled repeat low transverses Aryan

section at 39 weeks

our third preferred option is a failed

trial of labor after cesarean and she

still ultimately needs a caesarean

delivery this option has the highest

rates of maternal morbidity with higher

rates of bleeding and infection it is

important to weigh the risks and

benefits when making these decisions

with our patients the benefits of a

successful trial of labor after

caesarean delivery are that you avoid

surgery which needs to lower rates of

hemorrhage infection and you’ll have

shorter recovery periods in addition

there are decreased future abnormal

placentation risks such as placenta

previa or placenta accreta uterine

rupture is the most feared complication

of a trial and labor after cesarean with

a history of one low transverse cesarean

section the risk of uterine rupture is

0.7 20.9% with a history of too low

trans vs. Aaron sections the risk of

rupture is 0.9 to 1.8% with a history of

a classical cesarean section the risk of

uterine rupture is 10% this high rupture

risk is why these women should have a

repeat cesarean delivery and not try to

labor when counseling patients who’ve

had a load trans versus Aaron section

different clinical factors have to be

taken into account that either increase

or decrease your probability of a

successful VBAC having a history of a

prior vaginal birth or if she presents

some spontaneous labor both increase

your probability of a successful VBAC

factors that increase her chance of a

failed trailer labor after caesarean

include increased maternal age non-white

ethnicity obesity a recurrent indication

for the initial cesarean delivery such

as labor dystocia increased neonatal

birth weight at gestational age greater

than 40 weeks preeclampsia and a short

enterprise-e interval ultimately labora

and her healthcare provider should

discuss and decide on a delivery plan

that factors in her individual clinical

factors as well as the availability of a

24 hour blood bank continuous electronic

fetal monitoring and other Hospital

factors such as in-house anesthesia that

will enable an expedient cesarean

delivery to be performed if necessary

this concludes the Africa video an

abnormal labor we have discussed the

three P’s to consider in evaluating

labor discuss fetal and maternal

complications of abnormal labor

discussed oxytocin and risks and

benefits of trial of labor after

disgust management of emergent of

technical situations

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Basic Obstetrics & Gynecology

Basic Obstetrics & Gynecology

31. fetal growth abnormalities.

Duration = 6:00

00:00 APGO educational topic number 31 fetal 00:03 growth abnormalities once upon a time 00:05 there was a medical student named 00:07 Goldilocks and she encountered three 00:09 pregnancies during her labor and 00:10 delivery rotation one pregnancy was big 00:13 one pregnancy was small and the third 00:15 pregnancy was just right in this video 00:18 we will discuss definitions significance 00:20 and management issues for fetal growth 00:22 abnormalities the objectives of this 00:24 video are to define macrosomia and fetal 00:26 growth restriction to describe the 00:28 ideologies of abnormal growth list 00:31 methods of detection for fetal growth 00:33 abnormalities describe the management of 00:36 fetal growth abnormalities and lastly 00:38 list the associated morbidity and 00:40 mortality of fetal growth abnormalities 00:42 let’s start with the pregnancy that was 00:44 big we will discuss the definition 00:46 significance and management issues with 00:48 fetal macrosomia fetal macrosomia is 00:51 defined as a very large fetus typically 00:53 between 4,000 and 4,500 grams the 00:56 morbidity sharply increases when the 00:58 fetus is greater than 4,500 grams there 01:01 are maternal and fetal causes of fetal 01:03 macrosomia maternal factors include a 01:05 history or macro stomach pregnancy 01:07 pregnancy weight gain parity and glucose 01:11 intolerance during pregnancy women with 01:13 gestational diabetes pre gestational 01:15 diabetes and even woman who failed their 01:17 one-hour glucose tolerance test with the 01:19 normal three-hour glucose tolerance test 01:20 or at increased risk for fetal 01:22 macrosomia there are fewer fetal factors 01:25 that are causes for fetal macrosomia but 01:27 these include being a male fetus and 01:28 having beckwith Wiedemann syndrome 01:31 moving on to significance there are 01:33 maternal and fetal risk for the fetal 01:35 macrosomia maternal risks include 01:37 postpartum hemorrhage vaginal laceration 01:39 and fetal risks include shoulder 01:41 dystocia clavicular fracture lower Apgar 01:44 scores and longer-term risk of being 01:46 overweight or obese later in life the 01:49 diagnosis of macrosomia can be 01:51 challenging many clinicians measure the 01:53 fundal height above the maternal 01:54 symphysis pubis this measurement is 01:56 commonly performed however is a poor 01:58 predictor of fetal macrosomia and should 02:00 be used in combination with clinical 02:02 palpation of estimated fetal weight 02:04 ultrasound derived estimated fetal 02:06 weights are associated with significant 02:08 error when the fetus is macro stomach 02:10 and the true value of ultrasounds is in 02:12 out macrosomia once the diagnosis of 02:15 fetal macrosomia is made the management 02:17 does not include induction of labor for 02:20 this does not decrease maternal or 02:22 neonatal morbidity and actually 02:24 increases the c-section risk the 02:26 American College of Obstetricians and 02:27 Gynecologists recommends a primary 02:29 cesarean section if an estimate of fetal 02:32 weight is greater than 5,000 grams for a 02:34 patient without diabetes or 4,500 grams 02:37 for a patient with diabetes let’s now 02:39 move to fetal growth restriction which 02:41 describes infants whose weights are 02:43 lower than expected the definition of 02:45 intrauterine growth restriction or IUGR 02:47 is when the fetus is less than the 10th 02:49 percentile remember that this means that 02:51 the prevalence of IUGR is approximately 02:54 9% therefore the change in percentile 02:56 over time may be the more important 02:58 measurement the significance of the 03:01 diagnosis is that the goal is to try to 03:03 identify infants who are at risks of 03:04 short-term and long-term morbidity or 03:06 mortality the short-term risk so that 03:09 small fetuses potentially lack adequate 03:11 reserve to either continue intrauterine 03:13 existence or potentially may lack 03:15 reserve to undergo the stress of labor 03:17 the long-term risk so that alterations 03:20 and fetal growth may have lifelong 03:21 implications it may predict health risks 03:24 such as a cardiovascular disease insulin 03:26 resistance and adult obesity in general 03:29 the smaller the fetus the greater the 03:31 risk of morbidity and mortality it’s 03:33 important to discuss early onset IUGR 03:36 versus late onset IUGR early in 03:39 pregnancy fetal growth is primarily 03:41 through cellular hyperplasia thus early 03:43 onset IUGR can lead to irreversible 03:46 decreases of organ size and possible 03:48 function later in the pregnancy fetal 03:52 growth is primarily secondary to 03:53 cellular hypertrophy so IUGR at this 03:56 point is more amenable to restoration of 03:58 fetal size with adequate nutrition 04:00 maternal factors associated with early 04:02 onset IUGR include maternal infections 04:05 such as rubella varicella or CMV smoking 04:09 multiple pregnancies and chronic 04:11 maternal disease late onset IUGR on the 04:14 other hand is usually secondary to 04:16 uterus until insufficiency the diagnosis 04:19 of IUGR is similar to the diagnosis of 04:21 macrosomia in that fundal height and 04:23 clinical palpation of an estimated fetal 04:25 weight 04:26 helpful clinicians suspect IUGR 04:28 ultrasound can be utilized to estimate 04:31 the fetal weight in addition Doppler 04:32 velocity of fetal vessels is very 04:34 important in the management of IUGR the 04:37 uterine artery systolic to diastolic 04:39 ratio evaluates the fetal placental 04:41 circulation as placental resistance 04:43 increases diastolic flow decreases 04:46 therefore there is an increase in the 04:48 systolic and diastolic ratio absent or 04:52 reversed end diastolic flow predicts a 04:54 worse perinatal outcome and is usually 04:56 an indication for delivery the middle 04:59 cerebral artery or MCA dopplers reflects 05:02 fetal adaptation this is because the 05:05 fetus always tries to spare the fetal 05:07 brain circulation when there is 05:08 decreased placental perfusion there is 05:10 increased mca doppler flow moving now to 05:14 management the goal is to deliver the 05:16 healthiest possible infant at the 05:17 optimal time fetal surveillance is 05:20 important with continued management of 05:21 the pregnancy based on the results of 05:23 fetal testing the gestational age of the 05:25 fetus and the known risks associated 05:27 with prematurity all need to be factored 05:29 into the decisions regarding the timing 05:31 of delivery and delivery should 05:33 optimally be performed when the risk of 05:34 fetal death is greater than the risk of 05:36 neonatal death this concludes the aapko 05:39 video on fetal growth abnormalities we 05:41 have discussed the definitions 05:42 significance and management of fetal 05:44 macrosomia and IUGR 05:59 you

3rd Year Medical Student Clerkship

IMAGES

  1. Topic 22: Abnormal Labor

    educational topic 22 abnormal labor

  2. PPT

    educational topic 22 abnormal labor

  3. Abnormal labor: Clinical practice: Video & Anatomy

    educational topic 22 abnormal labor

  4. Abnormal labor: Clinical practice: Video & Anatomy

    educational topic 22 abnormal labor

  5. ABNORMAL LABOR ( Causes, Signs, Complications, Management)

    educational topic 22 abnormal labor

  6. Abnormal labor (updated lecture)

    educational topic 22 abnormal labor

VIDEO

  1. Abnormal

  2. Multiple Process accounts with normal loss, abnormal loss, and abnormal gain/Malayalam

  3. Did COVID cause my POTS? Dr. Diana Driscoll answers on Livestream

  4. Chronic Law

  5. ABNORMAL LABOR & DELIVERY

  6. Normal and Abnormal Labor 🤗

COMMENTS

  1. PDF Educational Topic 22: Abnormal Labor

    Educational Topic 22: Abnormal Labor. Rationale: Labor is expected to progress in an orderly and predictable manner. Careful observation of the mother and fetus during labor will allow for early detection of abnormalities so that management can be directed to optimize outcome.

  2. PDF Educational Topic 22: Abnormal Labor

    Microsoft Word - TC22 CC.docx. EDUCATIONAL OBJECTIVES, 10TH. UNIT 2: OBSTETRICS SECTION B: ABNORMAL OBSTETRICS. Educational Topic 22: Abnormal Labor. Rationale: Labor is expected to progress in an orderly and predictable manner. Careful observation of the mother and fetus during labor will allow for early detection of abnormalities so that ...

  3. PDF Educational Topic 22: Abnormal Labor

    Educational Topic 22: Abnormal Labor Labor is expected to progress toward delivery in a predictable manner. Close monitoring of the labor curve and early recognition of abnormal labor allows intervention to achieve a safe, healthy . birth for the mother and infant. Communication with the laboring woman and her social supports,

  4. Topic 22: Abnormal Labor

    The Association of Professors of Gynecology and Obstetrics (APGO) Medical Student Educational Objectives define a central body of women's health knowledge, s...

  5. Topic 22: Abnormal Labor

    The Association of Professors of Gynecology and Obstetrics (APGO) Medical Student Educational Objectives define a central body of women's health knowledge, skills and attitudes that are fundamental to the practice of a general physician, and are intended to provide clerkship directors, faculty and students with a resource for curriculum development, teaching and learning. The companion ...

  6. PDF Apgo Medical Student Educational Objectives

    22. Abnormal Labor..... 37 23. Third Trimester Bleeding..... 39 . APGO MEDICAL STUDENT EDUCATIONAL OBJECTIVES 11TH EDITION 2019 Association of Professors of Gynecology and Obstetrics ... The 64 educational topic areas serve as a table of . contents and are useful in organizing the curriculum for teaching and evaluation. All educational topic

  7. APGO Medical Student Educational Objectives for Students

    22 Abnormal Labor. MSO Video Teaching Case - Student-Fillable. 23 Third Trimester Bleeding. MSO Video Teaching Case - Student-Fillable. 24 Preterm Labor. MSO Video Teaching Case - Student-Fillable. 25 Premature Rupture of Membranes. MSO Video Teaching Case - Student-Fillable. 26 Intrapartum Fetal Surveillance. MSO Video Teaching Case ...

  8. 22. Abnormal Labor

    Epico educational topic number 22. 00:02. abnormal labor you may remember our. 00:04. patient labora deliver it from our app. 00:06. go video number eleven intrapartum care. 00:09. we follow libera through a normal labor. 00:11. and delivery course in that video in. 00:13. this video labora will experience. 00:15. abnormal labor we will discuss ...

  9. Abnormal Labor

    Introduction. Normal labor is defined as regular uterine contractions resulting in progressive cervical effacement and dilation. Abnormal labor refers to labor patterns deviating from delineated normal standards. A clear understanding of normal labor progression is essential to recognize dysfunctional labor. [1]

  10. Abnormal labor: Clinical: Video, Anatomy & Definition

    Abnormal labor is defined as the abnormal onset of labor - either too early or too late in the pregnancy - or abnormal duration of the stages of labor.. Normally, labor onset occurs between weeks 37 and 42 of pregnancies, and labor itself has three stages. Stage I is when the cervix dilates to 10 centimeters, and it's divided into a latent phase, covering dilation from 0 to 6 centimeters ...

  11. Labor: Diagnosis and management of an abnormal first stage

    This topic will discuss diagnosis and management of abnormalities of the active phase of the first stage of labor. An overview of labor progress, risk factors for protraction and arrest disorders, diagnosis and management of abnormalities of the latent phase and second stage, and management of normal labor and delivery are reviewed separately ...

  12. PDF 8th edition Objectives

    The committee began with the 64 Educational Topic Areas and the underlying educational objectives published in the Objectives 7th edition. Three of these Educational Topic Areas were considered ... 22 Abnormal Labor 23 Third-Trimester Bleeding 24 Preterm Labor 25 Preterm Rupture of Membranes 26 Intrapartum Fetal Surveillance

  13. Abnormal Labor and Intrapartum Fetal Surveillance

    Abnormal Labor and Intrapartum Fetal Surveillance. This chapter deals primarily with APGO Educational Topic Areas: TOPIC 22 ABNORMAL LABOR. TOPIC 26 INTRAPARTUM FETAL SURVEILLANCE. Students should be able to distinguish characteristics of normal and abnormal labor using the physical examination as well as fetal monitoring and tocometry.

  14. PDF Educational Topic 22: Abnormal Labor

    Educational Topic 22: Abnormal Labor. Rationale: Labor is expected to progress toward delivery in a predictable manner. Close monitoring of the labor curve and early recognition of abnormal labor allows intervention to achieve a safe, healthy birth for the mother and infant. Communication with the laboring woman and her social supports ...

  15. PDF Educational Topic 11: Intrapartum Care

    TEACHING CASE. CASE: A 23-year old G1P0 woman at 38 weeks gestation comes to Labor and Delivery complaining of a 5-hour history of painful contractions occurring every 5 minutes and lasting 45-60 seconds in duration. She denies leaking of fluid per vagina, but has noted bloody show. She reports normal fetal movement.

  16. 22-Abnormal Labor-updated student.pdf

    View 22-Abnormal Labor-updated student.pdf from ENDOCRINOL 556 at Indiana University, Purdue University, Indianapolis. APGO MEDICAL STUDENT EDUCATIONAL OBJECTIVES, 11TH EDITION Teaching Case Student ... 1 Educational Topic 22: Abnormal Labor Rationale: Labor is expected to progress toward delivery in a predictable manner. Close monitoring of ...

  17. PDF APGO Medical Student Educational Objectives

    UNIT 1: APPROACH TO THE PATIENT. Educational Topic 3: Pap Test and DNA Probes/Cultures. Rationale: The Pap Test is one of the most effective screening tests used in medicine today. Proper technique in performing the Pap Test and obtaining specimens for DNA probes and/or microbiologic culture will improve accuracy.

  18. Educational Topic 22: Abnormal Labor Rationale: Labor is expected

    Educational Topic 22: Abnormal Labor Rationale: Labor is expected to progress in an orderly and predictable manner. Careful observation of the mother and fetus during labor will allow for early detection of abnormalities so that management can be directed to optimize outcome. Intended Learning Outcomes: A student should be able to: • List ...

  19. Abnormal Labor

    5 Topics Internal Pelvic Anatomy. History. Pap Test and DNA Probes and Cultures. ... Intrapartum Fetal Surveillance. Postpartum Care. Lactation. 3: Abnormal Obstetrics 13 Topics Spontaneous Abortion. Ectopic Pregnancy. Multifetal Gestation. Preeclampsia-Eclampsia. Fetal Growth Abnormalities. Third Trimester Bleeding. Preterm Labor ...

  20. Case22help.pdf

    Unformatted text preview: APGO MEDICAL STUDENT EDUCATIONAL OBJECTIVES, 10TH EDITION TEACHING CASES UNIT 2: OBSTETRICS SECTION B: ABNORMAL OBSTETRICS Educational Topic 22: Abnormal Labor Rationale: Labor is expected to progress in an orderly and predictable manner. Careful observation of the mother and fetus during labor will allow for early detection of abnormalities so that management can be ...

  21. Safe Prevention of the Primary Cesarean Delivery

    Featuring Clinical Topics. Breast Neoplasms; Delivery of Health Service; Fetal Intoxicant Spectrum Disorders

  22. Library Resources for Medical Clerkships and Clinical Electives

    APGO Medical Student Educational Objectives. Association of Professors of Gynecology and Obstetrics (APGO) Topic 13: Postpartum Care Topic 22: Abnormal Labor Topic 27: Postpartum Hemorrhage Topic 28: Postpartum Infection Topic 29: Anxiety and Depression Topic 37: Pelvic Floor Disorders

  23. 31. Fetal Growth Abnormalities

    APGO educational topic number 31 fetal 00:03 growth abnormalities once upon a time 00:05 there was a medical student named 00:07 Goldilocks and she encountered three 00:09 pregnancies during her labor and 00:10 delivery rotation one pregnancy was big 00:13 one pregnancy was small and the third 00:15 pregnancy was just right in this video 00:18