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Abnormal labor encompasses deviations from the expected progression of childbirth, which is typically characterized by regular, painful uterine contractions that produce progressive cervical effacement and dilation. The normal process is divided into 3 stages, involving cervical dilation, fetal delivery, and placental expulsion. Abnormalities may arise in any stage, presenting as prolonged, protracted, or arrested progression of labor. Classification is guided by defined time parameters outlined by the American College of Obstetricians and Gynecologists and the World Health Organization. Contributing factors include inadequate uterine contractions, cephalopelvic disproportion, fetal malposition, or soft tissue obstruction. Early recognition and timely management of abnormal labor are essential to minimizing maternal and fetal morbidity, reducing the risk of unnecessary cesarean delivery, and optimizing obstetric outcomes. Clinicians must understand physiologic labor patterns and pathologic variations to guide appropriate interventions. Participation in this course equips clinicians with practical knowledge to identify and evaluate normal and abnormal labor progress using standardized assessment tools and evidence-based guidelines. Learners develop skills to recognize complications such as dystocia, arrest disorders, and fetal distress, and to implement timely management strategies. The course emphasizes patient-centered care, effective communication, and interprofessional collaboration among obstetric clinicians, midwives, anesthesiologists, nurses, and neonatologists. This collaborative approach ensures coordinated decision-making during labor, enhances maternal safety, and improves neonatal outcomes. By strengthening competence in labor assessment, timely intervention, and multidisciplinary teamwork, participants are prepared to deliver safer, higher-quality obstetric care that reduces complications and supports optimal birth experiences. Objectives: Differentiate between first, second, and third-stage abnormalities to determine targeted interventions for each phase of labor. Assess cervical dilation, effacement, uterine contraction strength, and labor progress using validated tools such as the partograph. Evaluate outcomes of obstetric interventions to refine practice patterns and align with quality improvement metrics.

Differentiate between first, second, and third-stage abnormalities to determine targeted interventions for each phase of labor. Assess cervical dilation, effacement, uterine contraction strength, and labor progress using validated tools such as the partograph. Evaluate outcomes of obstetric interventions to refine practice patterns and align with quality improvement metrics. Collaborate with an interprofessional healthcare team to manage abnormal labor and coordinate a comprehensive obstetrical care plan. Access free multiple choice questions on this topic.

Normal labor is defined as regular and painful uterine contractions resulting in progressive cervical effacement and dilation. Abnormal labor refers to labor patterns that deviate from established normal standards. A clear understanding of normal labor progression is crucial for recognizing dysfunctional labor.[1] Labor consists of 3 stages: the first stage begins with painful 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 begins with complete cervical dilation and concludes with the delivery of the fetus. This stage is characterized by active maternal expulsive efforts to facilitate birthing. The third stage of labor begins with the 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 2–4 or more hours to assess labor progress. The American College of Obstetricians & Gynecologists (ACOG) defines the stages and phases of labor as follows: First Stage: 0 to 10 cm cervical dilation Latent phase: 0 to 5 cm dilation Active phase: 6 cm dilation to complete cervical dilation Second Stage: begins at 10 cm dilation; uterine contractions, along with maternal expulsive efforts, lead to the descent of the presenting fetal part and delivery of the fetus Third Stage: time between delivery of the fetus and placental delivery In 2020, the World Health Organization (WHO) launched a new Labor Care Guide, comprising 7 sections. This care guide defines the start of the active phase of labor as 5 cm. The International Federation of Gynecology and Obstetrics (FIGO) supports this care guide and recommends implementation in all obstetrical settings.[4] Notably, a discrepancy among international guidelines regarding the onset of active labor. As stated above, ACOG defines active labor as beginning at 6 cm of cervical dilation. 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 considered when classifying labor as abnormal:

In 2020, the World Health Organization (WHO) launched a new Labor Care Guide, comprising 7 sections. This care guide defines the start of the active phase of labor as 5 cm. The International Federation of Gynecology and Obstetrics (FIGO) supports this care guide and recommends implementation in all obstetrical settings.[4] Notably, a discrepancy among international guidelines regarding the onset of active labor. As stated above, ACOG defines active labor as beginning at 6 cm of cervical dilation. 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 considered when classifying labor as abnormal: First Stage Prolongation, Protraction, and Arrest Latent Phase Prolongation Nulliparous: The latent phase duration is longer than 20 hours Multiparous: The latent phase duration is longer than 14 hours Due to its variable and slow progression, latent phase prolongation alone does not indicate cesarean delivery. Active Phase Protraction and Arrest (once 6 cm cervical dilation is achieved) 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.[5] Second Stage Protraction and Arrest Nulliparous: The second stage duration is longer than 3 hours without an epidural or 4 hours with an epidural. Multiparous: The second stage duration is longer than 2 hours without an epidural or 3 hours with an epidural. Longer durations may be appropriate when maternal and fetal statuses are reassuring and the fetal presenting part continues to descend. ACOG recommends that second-stage labor arrest be diagnosed earlier with a lack of fetal descent and rotation despite adequate expulsive efforts, contractions, and time.[5] Third Stage Abnormality Placental retention duration is longer than 30 minutes following fetal delivery. The risk of adverse maternal outcomes increases after a third stage of 15 minutes.[1][6]

Normal labor progression requires consideration of the 3 "Ps," representing power, passage, and passenger. Power refers to uterine contractions and maternal expulsive efforts. The passage is the maternal pelvis, and the fetus is the passenger. Abnormal labor progression may be related to 1 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 the sole etiologies of abnormal labor progression or dystocia.[7] Labor abnormalities due to unfavorable fetal or maternal pelvic dynamics may require a cesarean delivery.[8] Uncommonly, a Bandl ring may be associated with protracted or arrested labor. A Bandl ring constricts between the thicker upper contractile and thinner lower uterine segments. Why this constriction develops during parturition is unclear—although prolonged labor and labor dystocia have been suggested as possible causes.[9] Risk Factors Associated with Abnormal Labor Maternal Factors Advanced maternal age Bandl ring 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 Obesity Labor induction Fetal Factors High fetal station at full cervical dilation Macrosomia Malpresentation Fetal anomalies Nonreassuring fetal heart rate tracing [10]

Abnormalities of labor are common worldwide. Pelvic shape varies significantly among women, and the fit between the maternal pelvis and fetus is exceptionally tight, unlike in other primates.[11] Approximately 20% of all labor involves protraction and/or arrest disorders. Disorders of labor are the most common reason for primary cesarean sections.[12] 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 labor's first and second stages.[13] There is currently no evidence-based consensus on what constitutes arrest during the latent phase of labor. Therefore, according to ACOG, in cases where both maternal and fetal conditions remain reassuring, cesarean delivery solely due to a prolonged latent phase should be avoided. For patients undergoing labor induction, the term “failed induction” is more appropriate when there is no cervical change during the latent phase, rather than labeling it as latent phase arrest. A prolonged first stage of labor may result in adverse outcomes for both mother and neonate.[5] 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 using 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.[14]

The pathophysiology of abnormal labor is poorly understood. Friedman initially established a labor curve for the expected timeframe of the first stage of labor; however, it has since been contemporized by Zhang et al.[15] 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 does not vary significantly, regardless of whether labor is spontaneous or induced. Insufficient uterine activity is the most common reason for a labor abnormality in the first stage of labor.[16] Labor is a physically intensive process, and prenatal exercise may play a role in increased uterine contractility. Increased physical activity levels have been associated with higher levels of oxytocin and decreased need for induction and augmentation of labor.[17] Maternal inactivity during pregnancy may be associated with prolonged labor. Results from a prospective cohort study showed that 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.[17] For these and other reasons, regular prenatal exercise is highly encouraged.

Labor begins with regular, painful 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 examination, providing an estimated fetal weight and an assessment of fetal presentation. Continuous monitoring of uterine activity discerns how frequently contractions occur. Internal pressure catheter monitoring measures the actual strength of uterine contractions. Fetal heart rate tracing may provide reassurance of fetal well-being throughout the labor process; however, the interpretation is highly varied and not diagnostic of fetal acidemia. 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 determine the fetal position, station, and descent of the presenting part, which is crucial in assessing the normal or abnormal progression of labor.[22]

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. MVUs are calculated by adding the sum of the net contraction pressures over 10 minutes. Adequate uterine activity is targeted at 200 to 250 MVUs.[23] Although this method of assessing uterine contractions has limitations, a more valuable and accurate system has yet to be devised. Electrohysterography is a recent technique that uses externally applied abdominal electrodes to monitor and record the electrical voltages generated by myometrial contractions. This method of assessing uterine contractility is not currently part of standard clinical practice.[23] Evaluating the fetal position is another crucial component of intrapartum care and management. Several studies' results 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 trial results 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. Manual rotation is more effective than maternal repositioning in labor for rotating the fetal head, and it involves less technical skill and lower risk than instrumental rotation.[24]

Abnormal labor progression is associated with multiple poor maternal and fetal outcomes. Therefore, active management is crucial to prevent adverse outcomes for the mother and the baby. Most labor and delivery units have an established protocol for administering oxytocin to augment inadequate contractions. This entails administering the proper medication, 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 prolonged labor, protraction, and arrest, especially during the active phase of labor. Manual placental extraction may be required for a prolonged third stage of labor. Prolonged or Protracted First Stage Latent Phase The latent phase can last for many hours or even days. Hence, the decision to admit the patient to the hospital depends on various factors, including the patient's cervical status, emotional state, associated complications, tolerance to pain, and physical 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.[25] Therapeutic rest may be considered if desired. Morphine may be administered intramuscularly and intravenously simultaneously at 5 to 10 mg, with a maximum total dose of 20 mg. Alternatively, intramuscular morphine sulfate and promethazine may be used.[26] Oxytocin and amniotomy may be helpful in actively treating a prolonged latent phase. Propranolol use does not increase the chances of vaginal delivery or shorten the time to delivery in nulliparous patients with a prolonged latent phase of labor.[27]

Therapeutic rest may be considered if desired. Morphine may be administered intramuscularly and intravenously simultaneously at 5 to 10 mg, with a maximum total dose of 20 mg. Alternatively, intramuscular morphine sulfate and promethazine may be used.[26] Oxytocin and amniotomy may be helpful in actively treating a prolonged latent phase. Propranolol use does not increase the chances of vaginal delivery or shorten the time to delivery in nulliparous patients with a prolonged latent phase of labor.[27] When both maternal and fetal conditions are stable, cesarean delivery for failed induction during the latent phase can often be avoided. Current ACOG recommendations suggest continuing oxytocin infusion for a minimum of 12 to 18 hours following membrane rupture before determining that the induction was unsuccessful. Beyond this timeframe, the decision to extend induction efforts should be guided by individual clinical factors, patient preferences, and a thorough discussion of the potential risks and benefits.[5] Most patients in the latent phase of labor, even when prolonged, will achieve a vaginal delivery with continuation of the induction.[5] Active Phase For women with a prolonged or protracted active phase of the first stage, oxytocin may be administered, and an amniotomy may be performed. Suppose there has been no cervical change after 4 hours of adequate uterine contractions (>200 MVUs) and ruptured membranes or 6 hours with adequate uterine contractions, ruptured membranes, and oxytocin augmentation. In that case, 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 tracing is reassuring, any operative intervention should be delayed. If necessary, manual rotation of the fetus from an occiput posterior presentation to an occiput anterior presentation can be attempted in a protracted second stage.

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 tracing is reassuring, any operative intervention should be delayed. If necessary, manual rotation of the fetus from an occiput posterior presentation to an occiput anterior presentation can be attempted 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 before proceeding to cesarean delivery when the second stage of labor is protracted.[5][28] European Guidelines for Managing Arrested or Protracted Labor in Nulliparous Women in the First Stage of Labor at Term In 2022, an expert panel convened by the European Association of Perinatal Medicine, including obstetricians, gynecologists, midwives, and patient representatives from 9 European countries, developed evidence-based clinical guidelines for managing labor. Supported by the Knowledge Institute of the Dutch Association of Medical Specialists, the panel focused on 5 priority clinical questions concerning term, nulliparous women with a singleton fetus in cephalic presentation experiencing arrested or protracted labor due to inadequate uterine contractions. Key recommendations include considering amniotomy as an initial intervention and discussing the timing of oxytocin administration, immediate versus delayed, with patients, as current evidence does not clearly favor 1 approach.

In 2022, an expert panel convened by the European Association of Perinatal Medicine, including obstetricians, gynecologists, midwives, and patient representatives from 9 European countries, developed evidence-based clinical guidelines for managing labor. Supported by the Knowledge Institute of the Dutch Association of Medical Specialists, the panel focused on 5 priority clinical questions concerning term, nulliparous women with a singleton fetus in cephalic presentation experiencing arrested or protracted labor due to inadequate uterine contractions. Key recommendations include considering amniotomy as an initial intervention and discussing the timing of oxytocin administration, immediate versus delayed, with patients, as current evidence does not clearly favor 1 approach. A shared decision-making model is emphasized, incorporating clinical judgment and patient preferences. When oxytocin is indicated, a low-dose regimen is recommended for labor augmentation. Importantly, amniotomy should generally precede oxytocin infusion during the first stage of spontaneous labor. Before proceeding to operative delivery, at least 4 hours of oxytocin augmentation with adequate uterine contractions should be attempted, provided maternal and fetal conditions remain stable. These guidelines aim to promote safe, individualized, and evidence-based labor management, improving outcomes for both mothers and infants. Similarly, the WHO recommends both amniotomy and oxytocin for labor augmentation, without using amniotomy alone. In many countries, amniotomy is typically performed as the initial intervention, and if there is no noticeable progress within 1 to 2 hours, intravenous oxytocin is then initiated to support labor advancement.[29]

When evaluating abnormal labor, it is essential to consider a broad differential diagnosis to identify underlying causes that may impede normal progression. A structured approach to the differential diagnosis helps clinicians distinguish correctable conditions from those requiring intervention, ultimately optimizing obstetric outcomes. The differential diagnosis of abnormal labor includes the following: Abdominal pain Bandl ring Braxton Hicks contractions Cervical stenosis Chorioamnionitis 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 of labor, intervention with amniotomy and oxytocin can be helpful and allow normal progression for the remainder of labor. These same strategies may be utilized in cases of abnormalities during 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.[30] Maternal and neonatal morbidity is associated with a prolonged first stage of labor, including maternal fever from endometritis, shoulder dystocia, hemorrhage, and blood transfusion.[31][32] A prolonged latent phase reaching the 90th percentile or higher in individuals who progress to active labor is linked to a higher risk of maternal complications, independent of whether a cesarean delivery occurs. 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.[32][33] Additionally, when a prolonged latent phase occurs during spontaneous labor, it is associated with an elevated risk of adverse neonatal outcomes.[34] The fetus has an increased risk of neonatal intensive care unit admission, low Apgar scores, and a need for assisted ventilation with abnormal labor.[33] Operative vaginal delivery may expedite the abnormal labor process in certain situations. Based on the recommended criteria, cesarean delivery is indicated with abnormal labor in the first and second stages.[35] Current methods to prevent injury, blood loss, and infection result in a good prognosis when cesarean delivery is necessitated.[24]

Roughly 20% of labor is 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 mother and baby, third- and fourth-degree maternal perineal lacerations, above-average blood loss, and neonatal intensive care unit admission are all increased with abnormal labor progress.[36] 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 parallel rise in maternal morbidity and mortality, as placenta accreta and placenta previa account for a large percentage of maternal morbidity and mortality.[37]

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 individuals 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 participate in their prenatal care and labor and delivery actively. 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 through regular exercise during pregnancy benefits both the mother and fetus. At least 1 randomized controlled trial's results have shown that walking in late pregnancy may decrease the need for labor induction, as well as operative vaginal delivery and cesarean section.[38] Taking steps to avoid significant weight gain in pregnancy, associated with gestational diabetes and fetal macrosomia, may help decrease the risks of abnormal labor.[39] Making informed decisions about the timing of labor induction can contribute to optimizing the labor process. Having a reliable support person and maintaining adequate nutrition and hydration during labor may also help reduce the occurrence of abnormal labor. Dysfunctional labor can be a frightening experience for patients. Adopting a disciplined interprofessional team approach to identifying and managing abnormal labor will lead to the most favorable outcomes for both the mother and baby.

Abnormal labor, or dystocia, is commonly caused by issues with the passenger (fetus), pelvis, or power (contractions); this may present as prolonged or arrested labor, and management includes monitoring, augmentation with oxytocin, or operative delivery if necessary. Key pitfalls include delayed recognition of arrest, misuse of oxytocin, and failure to assess fetal-pelvic compatibility. Prevention involves early risk identification, adequate labor support, and timely intervention when labor progress stalls.

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 clinicians, anesthesiologists, patients, support persons, and their families. 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, clinicians, and other obstetric caregivers face challenges related to care standardization and productivity overload demands. These challenges can potentially hinder the development of strong and meaningful patient relationships, leading to increased insensitivity and burnout among healthcare providers over time.[40] The outcome of abnormal labor depends on the labor stage and the abnormality's etiology. Improved outcomes require interprofessional communication, care coordination, and enhanced team performance with a focus on patient-centered care and safety.