INTRODUCTION — The second stage of labor begins when the cervix becomes fully dilated and ends with expulsion of the neonate. Recognizing abnormal labor progression in the second stage and initiating appropriate interventions are important because a prolonged second stage is associated with increased risks for operative delivery and maternal and neonatal morbidity.
This topic will discuss the diagnosis and management of a prolonged second stage of labor. An overview of labor progress, risk factors for protraction and arrest disorders, diagnosis and management of first stage labor abnormalities, 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 an abnormal first stage".)
●(See "Labor and delivery: Management of the normal first stage".)
BACKGROUND — The second stage of labor is typically much shorter than the first stage and characterized by considerable variation; it is often brief but may extend for many hours. The identification and management of prolonged second stage are based on expert consensus and agreed-upon definitions for what is normal and safe. Historically, analyses of second-stage duration have been descriptive, retrospective, and influenced by both demographic and obstetric factors, which have varied across time and practice settings. For example, demographic factors that may increase second-stage duration include nulliparity and high maternal body mass index. Obstetric factors include increased birth weight, high fetal station at complete dilation, occiput posterior position, neuraxial analgesia, delayed pushing, willingness to initiate oxytocin in the second stage, and the skill, judgment, and ability of the provider to safely perform a rotation or operative vaginal delivery.
A major focus of efforts to reduce the rate of primary cesarean births performed in the second stage is to allow a longer maximum time in the second stage before considering it prolonged. Reduction of the cesarean birth rate is an important goal, but must be balanced against the rare but considerable perinatal morbidity reported in prolonged second stage [1-7]. The diagnosis of a prolonged second stage per se does not imply delivery must occur, but should prompt reassessment of maternal and fetal status, labor progress, and the chances of vaginal birth. (See 'Risks of prolonging the second stage' below.)
DIAGNOSIS — The appropriate duration and maximum length of time allowed for the second stage of labor is somewhat controversial. A specific absolute maximum length of time spent in the second stage beyond which all patients should undergo operative delivery has not been identified. One consideration is that the start of the second stage is not precise because it is diagnosed when the cervix is completely dilated (usually defined as 10 cm), which might have occurred before the manual cervical examination that first detects complete dilation.
We diagnose a prolonged second stage based on an American College of Obstetricians and Gynecologists and Society for Maternal-Fetal Medicine consensus group statement for prevention of the primary cesarean birth:
●In nulliparous patients, the second stage generally can be considered prolonged:
•After three hours of pushing [8]. However, a longer duration (commonly, up to four hours of pushing) may be appropriate for patients with epidural anesthesia or with a fetal malposition as long as progress is documented.
●In parous patients, the second stage generally can be considered prolonged:
•After two hours of pushing [8]. However, a longer duration (commonly, up to three hours of pushing) may be appropriate for patients with epidural anesthesia or with a fetal malposition as long as progress is documented.
Concerning fetal or maternal status necessitates consideration of delivery prior to reaching the described time limits.
Clinical experience and judgment are of great importance in decision-making during the second stage of labor. Factors such as the fetal station, estimated fetal weight, obstetric history, fetal status, pelvic size and shape, and adequacy of maternal pushing should be considered. In select scenarios where the probability of a vaginal birth appears to be low, such as when a patient has been pushing effectively without any descent or rotation, it is reasonable to make a diagnosis of a prolonged second stage and proceed with operative birth prior to these times. On the other hand, a diagnosis of a prolonged second stage does not mandate prompt operative intervention when the maternal and fetal status is reassuring. (See 'Timing of operative delivery' below.)
Evidence and controversy — The contemporary criteria for diagnosis of a prolonged second stage were derived from an analysis of data from the Consortium on Safe Labor by Zhang et al [9], which we believe is the best guide for describing the normal duration for the second stage of labor (median and 95th percentile) in contemporary patients (table 1).
The criteria were validated by a randomized trial and large observational study.
●A randomized trial in 78 nulliparous patients compared the "old approach" to diagnosis of a second-stage arrest (two hours without epidural anesthesia or three hours with epidural anesthesia) with the "new approach" (three hours without epidural anesthesia or four hours with epidural anesthesia) before expediting delivery by an operative method [10]. Extending the duration of the second stage before diagnosis of arrest resulted in a 55 percent reduction in cesarean births (19.5 versus 43.2 percent, relative risk [RR] 0.45, 95% CI 0.22-0.93) without an increase in maternal and neonatal morbidity. However, the trial was underpowered to detect small but clinically important differences in the frequency of adverse outcomes between groups or provide a precise estimate of the cesarean birth rate. In addition, the durations of the second stage for each group were not significantly different, in part because 14 percent of the cohort crossed over from their assigned group.
●The largest observational study comparing the "old" and "new" approaches described in the bullet above included >19,000 low-risk pregnancies without fetal anomalies and confirmed that the new approach was associated with a reduction in cesarean births (for nulliparous patients: 15.7 versus 23.3 percent, adjusted relative risk [aRR] 0.63, 95% CI 0.58-0.70; for parous patients: 8.1 versus 10.9 percent; aRR 0.72, 95% CI 0.67-0.84) [11]. As with the prior trial, the individual risk for cesarean birth and morbidities associated with cesarean birth increased with increasing duration of the second stage.
The new approach has been challenged by some experts, including Emanuel Friedman, MD, who believe that the safety of extending the duration of the second stage to these lengths before making a diagnosis of arrest, particularly up to four hours in nulliparous patients with neuraxial anesthesia, has not been established [6,12,13]. Of potential concern, in the large observational study described above [11], the new approach was also associated with a 10-fold increase in cord pH ≤7.0 (0.48 versus 0.04 percent, RR 9.98, 95% CI 3.6-27.6); however, there was no increase in abnormal early neurological outcome, which was 0.1 percent with both approaches. The study also reported small increases in assisted vaginal births (19.2 versus 17.7 percent, adjusted RR 1.1, 95% CI 1.06-1.14), shoulder dystocia (0.4 versus 0.2 percent, RR 1.92, 95% CI 1.08-3.4), and neonatal intensive care unit admission (1.5 versus 1.0 percent, RR 1.53, 95% CI 1.18-1.98). This study has not prompted us to change our practice, given the large absolute reduction in cesarean births in this study and in the small randomized trial described above [10], and the absence of strong evidence of large or clinically important maternal, fetal, or neonatal harm with extending the second stage before making a diagnosis of arrest. However, we recommend increased vigilance when monitoring the fetal heart rate tracing and consideration of operative vaginal delivery, in some cases prior to reaching contemporary time criteria for diagnosis of a prolonged second stage. As discussed above (see 'Diagnosis' above), lack of progress or concerning fetal or maternal status should necessitate consideration of delivery prior to reaching the described time limits. Alternatively, reassuring assessment does not necessitate prolonging the second stage.
INCIDENCE AND PROGNOSIS — In a retrospective study including over 15,000 nulliparous term cephalic singleton births from 1976 to 2001 in which 56 percent of the entire cohort had epidural anesthesia, the frequency of patients giving birth during each hour of the second stage was as follows [3]:
●0 to 1 hours – 46 percent
●1 to 2 hours – 23 percent
●2 to 3 hours – 14 percent
●3 to 4 hours – 10 percent
●>4 hours – 7 percent
The route of birth among patients who gave birth during each hour was:
●0 to 1 hours – nearly 100 percent vaginal (spontaneous or assisted)
●1 to 2 hours – nearly 100 percent vaginal (spontaneous or assisted)
●2 to 3 hours – nearly 95 percent vaginal (spontaneous or assisted)
●3 to 4 hours – approximately 85 percent vaginal (spontaneous or assisted)
●>4 hours – 67 percent vaginal (spontaneous or assisted)
In a similar retrospective study of over 5000 multiparous patients, of whom 44 percent had epidural, the frequency of patients giving birth during each hour of the second stage was as follows [4]:
●0 to 1 hours – 80 percent
●1 to 2 hours – 11 percent
●2 to 3 hours – 5 percent
●>3 hours – 5 percent
The route of birth among patients who gave birth during each hour was:
●0 to 1 hours – 96 percent vaginal (spontaneous or assisted)
●1 to 2 hours – 99 percent vaginal (spontaneous or assisted)
●2 to 3 hours – 93 percent vaginal (spontaneous or assisted)
●>3 hours – 73 percent vaginal (spontaneous or assisted)
MANAGEMENT
Approach to patients undelivered after pushing for 60 to 90 minutes — More than half of parturients who give birth vaginally will do so within 60 to 90 minutes of beginning to push, regardless of parity or use of neuraxial anesthesia (table 1). Reassessment is indicated for the remainder of patients who remain undelivered at this point in the second stage.
Patients with adequate descent and/or rotation — If descent is adequate (>1 cm over 60 to 90 minutes) and/or rotation from a non-occiput anterior (OA) position to OA occurred/is occurring, then we continue supportive care as long as the fetal heart rate pattern does not necessitate expeditious delivery. Most patients with this labor pattern will achieve a vaginal birth before meeting criteria for a prolonged second stage.
Patients with inadequate descent and/or rotation — If descent is minimal (<1 cm over 60 to 90 minutes), then the probable cause should be ascertained and treatment initiated. Possible causes include hypocontractility or a physical issue.
●Begin oxytocin augmentation in patients with hypocontractility – If uterine contractions are less frequent than every three minutes (ie, hypocontractility), oxytocin augmentation is initiated or the oxytocin dose is increased as long as the fetal heart rate pattern is reassuring. (See "Labor: Diagnosis and management of an abnormal first stage", section on 'Oxytocin dosing'.)
We continue supportive care as long as the fetal heart rate pattern is reassuring and the fetus continues to descend and criteria for a prolonged second stage have not been met. Absence of further descent with adequate contractions mandates clinical reassessment and consideration of operative delivery. (See 'Timing of operative delivery' below.)
●Provide coaching and guidance to optimize maternal expulsive efforts – Data on coached versus uncoached maternal pushing in uncomplicated labors during the second stage have failed to demonstrate significant benefits, although coaching is associated with a slightly shorter second stage [14]. We have not identified any studies evaluating the impact of coaching in the setting of inadequate descent. However, in our experience, the benefits of an experienced and engaged nurse or physician can be of substantial benefit for patients who are experiencing inadequate descent due to suboptimal expulsive efforts.
●Assess the likelihood of a physical issue and consider manual rotation – If descent is minimal (<1 cm) and uterine contractions and maternal expulsive efforts appear to be adequate, we consider the possibility of a physical issue (eg, malposition, macrosomia, small maternal pelvis) as the cause for slow descent and do not begin oxytocin augmentation.
An experienced obstetrician can diagnose fetal position digitally. Sonography can confirm or increase accuracy of fetal position. Manual rotation from the occiput posterior to OA position has a high success rate (especially if performed as soon as second stage descent slows), can shorten the second stage, and increase the chances of vaginal birth. The procedure is described separately (see "Occiput posterior position"). Similar considerations apply to occiput transverse position. (See "Occiput transverse position".)
We continue supportive care as long as the fetal heart rate pattern is reassuring and the fetus continues to descend and criteria for a prolonged second stage have not been met. Absence of further descent with adequate contractions mandates clinical reassessment and consideration of operative delivery for dystocia. (See 'Timing of operative delivery' below.)
Timing of operative delivery — Heightened clinical vigilance is warranted when approaching the diagnostic times for a prolonged second stage of labor. The options of an operative delivery (assisted-vaginal, cesarean) versus continued pushing are considered and discussed with the patient when approaching the times established for the upper limit of a normal second stage of labor (see 'Diagnosis' above). At that time, if the station and position do not permit a safe assisted-vaginal delivery and further progress seems unlikely, we advise cesarean birth. However, we will consider continuing the second stage beyond the time diagnostic of a prolonged second stage when, in our judgment, a safe assisted-vaginal or spontaneous birth seems to be achievable within the next 30 to 45 minutes. This is a shared decision; we discuss the options of continued pushing versus vacuum- or forceps-assisted vaginal delivery (if the patient is an appropriate candidate) versus cesarean birth. (See "Operative vaginal birth", section on 'Prerequisites'.)
Prompt operative intervention is required for fetuses with category III fetal heart rate tracings, regardless of labor progress. Category II tracings are managed on a case-by-case basis, given the wide spectrum and significance of category II patterns. (See "Intrapartum category I, II, and III fetal heart rate tracings: Management", section on 'Category II pattern (Indeterminate)'.)
Risks of prolonging the second stage — Whether to allow the duration of the second stage to extend beyond the times diagnostic of a prolonged second stage before operative intervention is controversial, as a prolonged second stage has potential clinical challenges and consequences [1-3,15]:
●If a cesarean birth becomes necessary, a prolonged second stage may result in the fetal head being trapped deep in the pelvis and further thinning of the lower uterine segment, both of which increase the chances of extension of the hysterotomy into the uterine vessels and surrounding tissues at cesarean. There are a variety of techniques to approach to reduce this risk, including changing the location of the uterine incision, assistance with elevation of the fetal head manually or mechanically, or reverse breech extraction. (See "Cesarean birth: Management of the deeply impacted head and the floating head", section on 'Reverse breech extraction ("pull method")'.)
●Prolonging the second stage increases the risk for occurrence of postpartum hemorrhage and maternal infection.
●Prolonging the second stage worsens neonatal outcome (eg, increased neonatal intensive care unit admission, neonatal sepsis).
Ultimately, the obstetrician's clinical experience and judgment, in concert with the patient's values and preferences, should guide management. Clinical factors associated with increased chances of safe vaginal delivery include:
●Descent is occurring
●Previous vaginal birth
●Absence of comorbidities that are likely to impact labor
●Pelvis is deemed adequate for vaginal birth (based on physical examination)
●Patient is not short (height <160 cm [63 inches]) or obese (body mass index ≥30.0 mg/kg2)
●Fetus is OA, with minimal caput and molding.
●Station is at least +2/5 cm
●Absence of maternal fever, which is presumptive of chorioamnionitis
●Estimated fetal weight is appropriate for gestational age (<95th percentile)
●Pushing appears to be effective and the patient is not exhausted
●Category I fetal heart rate pattern
●Patient desire to proceed with labor
Ineffective management interventions
●Turning down the epidural – A dense motor block may impair a patient's ability to push, but there is no strong evidence that turning down the neuraxial anesthetic in patients with a prolonged second stage is beneficial. In a meta-analysis including five trials in which patients with epidurals were randomly assigned to anesthetic discontinuation late in labor or continuation until birth, early discontinuation did not clearly reduce instrumental delivery (23 versus 28 percent, RR 0.84, 95% CI 0.61-1.15) or other adverse delivery outcomes [16]. (See "Adverse effects of neuraxial analgesia and anesthesia for obstetrics", section on 'Effects on the progress and outcome of labor'.)
●Changing maternal position – There is no strong evidence that a change in maternal position (eg, upright posture, lateral, or hands and knees position instead of supine) is useful for treatment of a prolonged second stage [17-19]. Patients should be encouraged to labor, push, and birth in the position they find most comfortable.
●Fundal pressure – Manual fundal pressure does not significantly shorten the duration of the second stage, although available data are low quality [20].
PREVENTION — There is no strong evidence that any intervention will prevent a prolonged second stage of labor. The following interventions have been studied.
●Delayed pushing – In a meta-analysis of 12 trials of pushing methods in over 5400 patients with epidural anesthesia, delayed pushing increased the overall duration of the second stage by a mean of 46 minutes compared with immediate pushing (95% CI 33-60 minutes) [21]. Delayed pushing also resulted in decreased overall duration of pushing by a mean of 28 minutes (95 % CI -43 to -12 minutes) and no significant difference in spontaneous vaginal birth (80.9 versus 78.3 percent, RR 1.05, 95% CI 1.00-1.10). Delayed pushing increased the risk for chorioamnionitis (9.1 versus 6.6 percent, RR 1.37, 95% CI 1.04-1.81) and low umbilical cord pH (2.7 versus 1.3 percent, 95% RR 2.00, 95% CI 1.30-3.07).
●Maternal position and technique – Neither maternal pushing position nor technique (eg, physiologic versus coached) appears to have a substantial effect on the length of the second stage, although an upright position for delivery may shorten the second stage by 3 to 10 minutes [19]. (See "Labor and delivery: Management of the normal second stage", section on 'Pushing'.)
●Physical activity/exercise:
•Pelvic floor muscle exercises – Training the muscles of the pelvic floor may prevent some cases of prolonged second stage. In the largest trial, 301 healthy nulliparous patients were randomly assigned to an antepartum pelvic floor muscle training program or usual care from 20 to 36 weeks of gestation [22]. Patients in the intervention group trained with a physiotherapist for one hour/week and were encouraged to perform 8 to 12 intensive pelvic floor muscle contractions twice daily.
The intervention group had fewer second stages over 60 minutes (21 versus 34 percent), but the overall duration of the second stage was similar for both groups (40 and 45 minutes, respectively), as was the rate of assisted-vaginal delivery (15 and 17 percent, respectively).
•Exercise – Exercise during pregnancy improves fitness but does not affect the length of labor. In two trials, patients randomly assigned to participation in an aerobic exercise program during pregnancy had the same overall duration of labor as those who received standard prenatal care [23,24]. Although the smaller trial (91 participants) observed a reduction in primary cesarean birth in the exercise group [23], the larger trial (855 participants) found no difference in labor outcomes [24].
In addition, it should be noted that patients who are not able to push because of a spinal cord injury tend to have a normal, or even short, second stage [25].
•Continuous labor support – In a meta-analysis of randomized trials, continuous one-to-one intrapartum support by trained or untrained individuals resulted in small but statistically significant improvements in pregnancy outcomes, such as shorter labor and higher spontaneous vaginal birth rate, across a variety of health care settings and socioeconomic and ethnic groups, although the length of the second stage was not specifically analyzed [26]. (See "Continuous labor support by a doula".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Labor".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Labor and delivery (childbirth) (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Background – Normal human labor, particularly the second stage, is often brief, but characterized by considerable variation. The identification and management of abnormalities of duration are based on expert consensus and agreed-upon definitions for what is normal and safe. A major focus of efforts to reduce the rate of primary cesarean births performed in the second stage is to allow a longer maximum time in the second stage before considering it prolonged. (See 'Background' above.)
●Diagnosis – We diagnose a prolonged second stage based on an American College of Obstetricians and Gynecologists and Society for Maternal-Fetal Medicine consensus group statement for prevention of the primary cesarean birth (See 'Diagnosis' above.):
•In nulliparous patients – The second stage generally can be considered prolonged:
-After three hours of pushing. However, a longer duration (commonly, up to four hours of pushing) may be appropriate for patients with epidural anesthesia or with a fetal malposition as long as progress is documented.
•In parous patients – The second stage generally can be considered prolonged:
-After two hours of pushing. However, a longer duration (commonly, up to three hours of pushing) may be appropriate for patients with epidural anesthesia or with a fetal malposition as long as progress is documented.
Concerning fetal or maternal status necessitates consideration of operative delivery prior to reaching the described time limits.
●Management
•For patients who have not met criteria for a prolonged second stage, we continue expectant management as long as the mother is stable, the fetal heart rate pattern does not necessitate urgent delivery, and the fetus continues to descend and/or rotate to a more favorable position. (See 'Approach to patients undelivered after pushing for 60 to 90 minutes' above.)
-If descent is <1 cm over the first 60 to 90 minutes of the second stage and contractions are less frequent than every three minutes, oxytocin is initiated.
-If contractions are adequate, but maternal expulsive efforts are suboptimal, coaching from an experienced and engaged nurse or physician can be helpful.
-If descent is minimal <1 cm over the first 60 to 90 minutes of the second stage and uterine contractions and maternal expulsive efforts are adequate, the possibility of a physical issue (eg, malposition, macrosomia, small maternal pelvis) should be considered. Fetal position can be diagnosed digitally, but with greater accuracy sonographically. Manual rotation from the occiput posterior to occiput anterior position has a high success rate, can shorten the second stage, and increase the chances of vaginal birth. Similar considerations apply to occiput transverse position.
•For patients approaching the times established for a prolonged second stage, if the station and position do not permit a safe assisted-vaginal delivery and further progress seems unlikely, we generally advise the patient to undergo cesarean birth. However, we will consider continuing the second stage beyond the time diagnostic of a prolonged second stage when, in our judgment, a safe assisted-vaginal or spontaneous birth seems to be achievable within the next 30 to 45 minutes. This is a shared decision; we discuss the options of continued pushing versus vacuum- or forceps-assisted vaginal delivery (if the patient is an appropriate candidate) versus cesarean birth. (See 'Timing of operative delivery' above.)
●Risks of a prolonged second stage – A prolonged second stage of labor is associated with small increases in neonatal and maternal complications. (See 'Risks of prolonging the second stage' above.)
