When to stop pushing: effects of duration of second-stage expulsion efforts on maternal and neonatal outcomes in nulliparous women with epidural analgesia

[Update on the management modalities of expulsive efforts during childbirth]

The second stage of labour includes both the passive and active stages, involving expulsive efforts. The management of this phase of labour aims to minimise the maternal and neonatal complications that could be associated with a prolonged active2nd stage, but also to limit medical interventions. On the maternal side, prolonged duration of expulsive effort appears to be correlated with increased postpartum haemorrhage, perineal injury and, in the long term, urinary and anal incontinence. From a neonatal viewpoint, expulsive efforts carry risks of neonatal acidosis, asphyxia, admission to the neonatal intensive care unit and trauma. Optimal management of expulsive efforts involves several strategies. Various aspects need to be addressed in order to optimise this management, including the timing of the start of expulsive efforts, comparing immediate pushing with delayed pushing, and the duration of expulsive efforts. In addition, it is important to examine the different pushing modalities, whether intense or moderate, using open or closed-glottis pushing, as well as the maternal position during pushing. According to the current literature, no specific technique or predefined duration appears to reduce the risk of neonatal or maternal complications. It therefore seems essential to adopt an individualised approach for each woman, placing her at the centre of the care and decision-making process, in order to take account of her preferences during childbirth.

The second stage of labor

The second stage of labor extends from complete cervical dilatation to delivery. During this stage, descent and rotation of the presenting part occur as the fetus passively negotiates its passage through the birth canal. Generally, descent begins during the deceleration phase of dilatation as the cervix is drawn upward around the fetal presenting part. The most common means of assessing the normality of the second stage of labor is to measure its duration, but progress can be more meaningfully gauged by measuring the change in fetal station as a function of time. Accurate clinical identification and evaluation of differences in patterns of fetal descent are necessary to assess second stage of labor progress and to make reasoned judgments about the need for intervention. Three distinct graphic abnormalities of the second stage of labor can be identified: protracted descent, arrest of descent, and failure of descent. All abnormalities have a strong association with cephalopelvic disproportion but may also occur in the presence of maternal obesity, uterine infection, excessive sedation, and fetal malpositions. Interpretation of the progress of fetal descent must be made in the context of other clinically discernable events and observations. These include fetal size, position, attitude, and degree of cranial molding and related evaluations of pelvic architecture and capacity to accommodate the fetus, uterine contractility, and fetal well-being. Oxytocin infusion can often resolve an arrest or failure of descent or a protracted descent caused by an inhibitory factor, such as a dense neuraxial block. It should be used only if thorough assessment of fetopelvic relationships reveals a low probability of cephalopelvic disproportion. The value of forced Valsalva pushing, fundal pressure, and routine episiotomy has been questioned. They should be used selectively and where indicated.

Optimizing the length of the second stage and management of pushing

Although the optimal length of the second stage of labor to minimize maternal and neonatal morbidities and optimize spontaneous vaginal delivery is not known, available evidence suggests that increasing length of the second stage is associated with increasing maternal and neonatal morbidity. Thus, evidence-based strategies to safely shorten the second stage, such as initiating pushing when complete dilation is reached among those with neuraxial anesthesia, is prudent. Many aspects of optimal management of the second stage of labor require future study to continue to guide clinical second-stage management.

Factors associated with spontaneous vaginal birth in nulliparous women: A descriptive systematic review

PROBLEM

Spontaneous vaginal birth (SVB) rates for nulliparous women are declining internationally.

BACKGROUND

There is inadequate understanding of factors affecting this trend overall and limited large-scale responses to improve women's opportunity to birth spontaneously.

AIM

To undertake a descriptive systematic review identifying factors associated with spontaneous vaginal birth at term, in nulliparous women with a singleton pregnancy.

METHODS

Quantitative studies of all designs, of nulliparous women with a singleton pregnancy and cephalic presentation, who experienced a SVB at term were included. Nine databases were searched (inception to October 2022). Two reviewers undertook quality appraisal; Randomised Controlled Trials (RCTs) with high risk of bias (ROB 2.0) and other designs with (QATSDD) scoring ≤ 50% were excluded.

FINDINGS

Data were abstracted from 90 studies (32 RCTs, 39 cohort, 9 cross-sectional, 4 prevalence, 5 case control, 1 quasi-experimental). SVB rates varied (13%-99%). Modifiable factors associated with SVB included addressing fear of childbirth, low impact antenatal exercise, maternal positioning during second-stage labour and midwifery led care. Complexities arising during pregnancy and regional analgesia were shown to decrease SVB and other interventions, such as routine induction of labour were equivocal.

DISCUSSION

Antenatal preparation (low impact exercise, childbirth education, addressing fear of childbirth) may increase SVB, as does midwifery continuity-of-care. Intrapartum strategies to optimise labour progression emerged as promising areas for further research.

CONCLUSION

Declining SVB rates may be improved through multi-factorial approaches inclusive of maternal, fetal and clinical care domains. However, the variability of SVB rates testifies to the complexity of the issue.

First and Second Stage Labor Management: ACOG Clinical Practice Guideline No. 8

PURPOSE

The purpose of this document is to define labor and labor arrest and provide recommendations for the management of dystocia in the first and second stage of labor and labor arrest.

TARGET POPULATION

Pregnant individuals in the first or second stage of labor.

METHODS

This guideline was developed using an a priori protocol in conjunction with a writing team consisting of one maternal-fetal medicine subspecialist appointed by the ACOG Committee on Clinical Practice Guidelines-Obstetrics and two external subject matter experts. ACOG medical librarians completed a comprehensive literature search for primary literature within Cochrane Library, Cochrane Collaboration Registry of Controlled Trials, EMBASE, PubMed, and MEDLINE. Studies that moved forward to the full-text screening stage were assessed by the writing team based on standardized inclusion and exclusion criteria. Included studies underwent quality assessment, and a modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation) evidence-to-decision framework was applied to interpret and translate the evidence into recommendation statements.

RECOMMENDATIONS

This Clinical Practice Guideline includes definitions of labor and labor arrest, along with recommendations for the management of dystocia in the first and second stages of labor and labor arrest. Recommendations are classified by strength and evidence quality. Ungraded Good Practice Points are included to provide guidance when a formal recommendation could not be made because of inadequate or nonexistent evidence.

Second stage duration and delivery outcomes among women laboring after cesarean with no prior vaginal delivery

BACKGROUND

We aimed to evaluate the association of the duration of the second stage with labor after cesarean (LAC) success and other outcomes among women with one prior cesarean delivery (CD) and no prior vaginal births.

METHODS

All women undergoing LAC that reached the second stage of labor from March 2011 to March 2020 were included in this retrospective cohort study. The primary outcome was the mode of delivery by second stage duration. The secondary outcomes included adverse maternal and neonatal outcomes. We allocated the study cohort into five groups of second stage duration. Further analysis compared <3 to ≥3 h of second stage based on prior studies. LAC success rates were compared. Composite maternal outcome was defined as the presence of uterine rupture/dehiscence, postpartum hemorrhage, or intrapartum/postpartum fever.

RESULTS

One thousand three hundred ninety seven deliveries were included. Vaginal birth after cesarean (VBAC) rates decreased as the second stage length time interval increased: 96.4% at <1 h, 94.9% at 1 to <2 h, 94.6% at 2 to <3 h, 92.1% at 3 to <4 h and 79.5% at ≥4 h (p < 0.001). Operative vaginal and CDs were significantly more likely as second stage duration time interval increased (p < 0.001). The composite maternal outcome was comparable among groups (p = 0.226). When comparing the outcomes of deliveries at <3 h versus ≥3 h, the composite maternal outcome and neonatal seizure rates were lower in the <3 h group (p = 0.041 and p = 0.047, respectively).

CONCLUSION

Vaginal birth after cesarean rates decreased as second stage time interval length increased. Even with prolonged second stage, VBAC rates remained relatively high. Increased risk of composite adverse maternal outcomes and neonatal seizures were observed when the second stage lasted 3 h or more.

Maternal and perinatal outcomes of prolonged second stage of labour: a historical cohort study of over 51,000 women

BACKGROUND

Prolonged second stage of labour has been associated with adverse maternal and perinatal outcomes. The maximum length of the second stage from full dilatation to birth of the baby remains controversial. Our aim was to determine whether extending second stage of labour was associated with adverse maternal and perinatal outcomes.

METHODS

A retrospective cohort study was conducted using routinely collected hospital data from 51592 births in Aberdeen Maternity Hospital between 2000 and 2016. The hospital followed the local guidance of allowing second stage of labour to extend by an hour compared to national guidelines since 2008 (nulliparous and parous). The increasing duration of second stage of labour was the exposure. Baseline characteristics, maternal and perinatal outcomes were compared between women who had a second stage labour of (a) ≤ 3 h and (b) > 3 h duration for nulliparous women; and (a) ≤ 2 h or (b) > 2 h for parous women. An additional model was run that treated the duration of second stage of labour as a continuous variable (measured in hours). All the adjusted models accounted for: age, BMI, smoking status, deprivation category, induced birth, epidural, oxytocin, gestational age, baby birthweight, mode of birth and parity (only for the final model).

RESULTS

Each hourly increase in the second stage of labour was associated with an increased risk of obstetric anal sphincter injury (aOR 1.21 95% CI 1.16,1.25), having an episiotomy (aOR 1.48 95% CI 1.45, 1.52) and postpartum haemorrhage (aOR 1.27 95% CI 1.25, 1.30). The rates of caesarean and forceps delivery also increased when second stage duration increased (aOR 2.60 95% CI 2.50, 2.70, and aOR 2.44 95% CI 2.38, 2.51, respectively.) Overall adverse perinatal outcomes were not found to change significantly with duration of second stage on multivariate analysis.

CONCLUSIONS

As the duration of second stage of labour increased each hour, the risk of obstetric anal sphincter injuries, episiotomies and PPH increases significantly. Women were over 2 times more likely to have a forceps or caesarean birth. The association between adverse perinatal outcomes and the duration of second stage of labour was less convincing in this study.

New insights on labor progression: a systematic review

The past 20 years witnessed an invigoration of research on labor progression and a change of thinking regarding normal labor. New evidence is emerging, and more advanced statistical methods are applied to labor progression analyses. Given the wide variations in the onset of active labor and the pattern of labor progression, there is an emerging consensus that the definition of abnormal labor may not be related to an idealized or average labor curve. Alternative approaches to guide labor management have been proposed; for example, using an upper limit of a distribution of labor duration to define abnormally slow labor. Nonetheless, the methods of labor assessment are still primitive and subject to error; more objective measures and more advanced instruments are needed to identify the onset of active labor, monitor labor progression, and define when labor duration is associated with maternal/child risk. Cervical dilation alone may be insufficient to define active labor, and incorporating more physical and biochemical measures may improve accuracy of diagnosing active labor onset and progression. Because the association between duration of labor and perinatal outcomes is rather complex and influenced by various underlying and iatrogenic conditions, future research must carefully explore how to integrate statistical cut-points with clinical outcomes to reach a practical definition of labor abnormalities. Finally, research regarding the complex labor process may benefit from new approaches, such as machine learning technologies and artificial intelligence to improve the predictability of successful vaginal delivery with normal perinatal outcomes.

Mode of delivery and birth outcomes in relation to the duration of the passive second stage of labour: A retrospective cohort study of nulliparous women

OBJECTIVE

To investigate the mode of delivery and birth outcomes in relation to the duration of the passive second stage of labour in nulliparous women.

METHODS AND FINDINGS

A retrospective cohort study of all nulliparous women (n = 1131) at two delivery units in Sweden. Maternal and obstetric data were obtained from electronic medical records during 2019. The passive second stage was defined as the complete dilation of the cervix until the start of the active second stage. The duration of the passive second stage was categorized into three groups: 0 to 119 min (0 to <2 h), 120-239 min (2- <4h) and ≥240 min (≥4h). Differences between the groups were examined using t-test and Chi2-tests and regression analyses were used to analyse adjusted odds ratio with 95% confidence intervals. The primary outcome was mode of delivery in relation to the duration of the passive second stage and the secondary outcomes covered a series of adverse maternal and neonatal birth outcomes. The rates of instrumental and caesarean deliveries increased as the duration of the passive second stage increased. A ≥4-hour duration of the passive second stage was associated with a nine-times increased risk of caesarean section, and a four-times risk of instrumental delivery compared to a duration of <2 hours in the adjusted analyses. No differences were found in the maternal birth outcomes. The risk of a 5-minute Apgar score <7 was increased in the 2-<4h group. A longer passive second stage was not associated with an increased risk of negative birth experience.

CONCLUSIONS

Our study demonstrates an increased risk of operative delivery for a longer duration (>2h) of the passive second stage in nulliparous women, although most of the women gave birth by spontaneous vaginal delivery even after ≥4 hours. There was no evidence of an increased risk of adverse maternal outcomes in a longer duration of the passive second stage but there were indications of increased adverse neonatal outcomes. Assessment of fetal well-being is important when the duration of the passive phase is prolonged.

Primary cesarean section rate among full-term pregnant women with non-previous uterine scar in a hospital of Vietnam

Aim

This article aims to determine the contributing indications for primary cesarean sections among full-term pregnant women with non-previous uterine scars and suggests several potential solutions to reduce the cesarean section rate.

Methods

This is a descriptive study with data being retrospectively collected from electronic medical records (EMRs) at Hanoi Obstetrics & Gynecology Hospital, Vietnam, in 2020. We studied 23,631 women at ≥37 weeks of gestation with non-previous uterine scars. Main ICD-10 categories of diagnosis on the EMRs were used to classify the indications. The proportions of indications for primary cesarean sections were calculated, thereby offering potential solutions to reduce the cesarean section rate.

Results

The proportion of cesarean sections among full-term pregnancies with non-previous uterine scars was 40.7%. The most common indications for primary cesarean sections were non-reassuring fetal heart rate tracing (40%), labor arrest (31%), and maternal request (11%). Among the low-risk pregnant women, the cesarean section rate was 35.9%, of which the percentages of labor arrest and non-reassuring fetal heart rate tracings and maternal request were 13.6%, 17.7%, and 4.6%, respectively.

Conclusions

The proportion of primary cesarean sections among full-term pregnancies with non-previous uterine scars is high; non-reassuring fetal heart rate tracings, labor arrest, and maternal request were three main indications. It is necessary to build the strategies of health organizations regarding the management of clinical practices and the programs improving the knowledge, attitudes, practices of pregnant women and obstetricians regarding cesarean sections.

Alternative to intensive management of the active phase of the second stage of labor: a multicenter randomized trial (Phase Active du Second STade trial) among nulliparous women with an epidural

BACKGROUND

There is no consensus on an optimal strategy for managing the active phase of the second stage of labor. Intensive pushing could not only reduce pushing duration, but also increase abnormal fetal heart rate because of cord compression and reduced placental perfusion and oxygenation resulting from the combination of uterine contractions and maternal expulsive forces. Therefore, it may increase the risk of neonatal acidosis and the need for operative vaginal delivery.

OBJECTIVE

This study aimed to assess the effect of the management encouraging "moderate" pushing vs "intensive" pushing on neonatal morbidity.

STUDY DESIGN

This study was a multicenter randomized controlled trial, including nulliparas in the second stage of labor with an epidural and a singleton cephalic fetus at term and with a normal fetal heart rate. Of note, 2 groups were defined: (1) the moderate pushing group, in which women had no time limit on pushing, pushed only twice during each contraction, and observed regular periods without pushing, and (2) the intensive pushing group, in which women pushed 3 times during each contraction and the midwife called an obstetrician after 30 minutes of pushing to discuss operative delivery (standard care). The primary outcome was a composite neonatal morbidity criterion, including umbilical arterial pH of <7.15, base excess of >10 mmol/L, lactate levels of >6 mmol/L, 5-minute Apgar score of <7, and severe neonatal trauma. The secondary outcomes were mode of delivery, episiotomy, obstetrical anal sphincter injuries, postpartum hemorrhage, and maternal satisfaction.

RESULTS

The study included 1710 nulliparous women. The neonatal morbidity rate was 18.9% in the moderate pushing group and 20.6% in the intensive pushing group (P=.38). Pushing duration was longer in the moderate group than in the intensive group (38.8±26.4 vs 28.6±17.0 minutes; P<.001), and its rate of operative delivery was 21.1% in the moderate group compared with 24.8% in the intensive group (P=.08). The episiotomy rate was significantly lower in the moderate pushing group than in the intensive pushing group (13.5% vs 17.8%; P=.02). We found no significant difference for obstetrical anal sphincter injuries, postpartum hemorrhage, or maternal satisfaction.

CONCLUSION

Moderate pushing has no effect on neonatal morbidity, but it may nonetheless have benefits, as it was associated with a lower episiotomy rate.

Associations between prolonged second stage of labor and maternal and neonatal outcomes in freestanding birth centers: a retrospective analysis

BACKGROUND

Current guidelines for second stage management do not provide guidance for community birth providers about when best to transfer women to hospital care for prolonged second stage. Our goal was to increase the evidence base for these providers by: 1) describing the lengths of second stage labor in freestanding birth centers, and 2) determining whether proportions of postpartum women and newborns experiencing complications change as length of second stage labor increases.

METHODS

This study is a retrospective analysis of de-identified client-level data collected in the American Association of Birth Centers Perinatal Data Registry, including women giving birth in freestanding birth centers January 1, 2007 to December 31, 2016. We plotted proportions of postpartum women and newborns transferred to hospital care against length of the second stage of labor, and assessed significance of these with the Cochran-Armitage test for trend or chi-square test. Secondary maternal and newborn outcomes were compared for dyads with normal and prolonged second stages of labor using Fisher's exact test.

RESULTS

Second stage labor exceeded 3 hours for 2.3% of primiparous women and 2 hours for 6.6% of multiparous women. Newborn transfers increased as second stage increased from < 15 minutes to > 2 hours (0.6% to 6.33%, p for trend = 0.0008, for primiparous women, and 1.4% to 10.6%, p for trend < 0.0001, for multiparous women.) Postpartum transfers for multiparous women increased from 1.4% after second stage < 15 minutes to greater than 4% for women after second stage exceeding 2 hours (p for trend < 0.0001.) CONCLUSIONS: Complications requiring hospitalization of postpartum women and newborns become more common as the length of the second stage increases. Birth center guidelines should consider not just presence of progress but also absolute length of time as indications for transfer.

Associations between duration of active second stage of labour and adverse maternal and neonatal outcomes: A cohort study of nulliparous women with spontaneous onset of labour

OBJECTIVE

To investigate associations between the duration of the active second stage of labour and adverse maternal and neonatal outcomes.

METHOD

This cohort study is based on data from a cluster randomised controlled trial (RCT) undertaken at 14 Norwegian birth clinics in Norway from 2014 to 2017. The final sample involved 6804 nulliparous women with a singleton fetus, cephalic presentation, spontaneous onset of labour at term, vaginal delivered and with an active second stage of labour. The women were grouped to active second stage of labour ≤ 60 min and active second stage of labour > 60 min. Binary logistic regression was used to estimate crude and adjusted odds ratios (ORs) of the maternal and neonatal outcomes with an associated 95% confidence intervals (CIs), comparing women in the two groups.

RESULTS

There was an increased risk of postpartum haemorrhage > 1000 ml with an adjusted OR 1.31 (95% CI: 1.01-1.69) when the active second stage of labour exceeded 60 min. There was no significant difference in the risk of obstetric anal sphincter injuries (adjusted OR 0.93 [95% CI: 0.65-1.39]), Apgar scores < 7 at 5 min age (adjusted OR 1.13 [95% CI: 0.65-1.97]) or admission to the neonatal intensive care unit (adjusted OR 1.46 [95% CI: 0.61-3.51]) between the study groups.

CONCLUSION

Women with an active second stage of labour that exceeds 60 min had an increased risk of postpartum haemorrhage > 1000 ml. We found no association between duration of active stage of labour and obstetric anal sphincter injuries or adverse neonatal outcomes.

Prolongation of active second stage of labor: Associated factors and perinatal outcomes

BACKGROUND

Current data does not allow to define a reasonable threshold of duration of active second stage (ASS) of labor beyond which a medical intervention should be considered. Primary objective was to analyse perinatal outcomes associated with prolonged ASS beyond 45 min. Secondarily, we analysed associated maternal, gestational, labor and delivery characteristics associated with prolonged ASS.

METHODS

We performed a monocentric retrospective study among women with vaginal delivery, a term singleton cephalic fetus, without history of cesarean section. We compared women with active second stage of labor longer than 45 min (ASS ≥45 min, group A) and women with instrumental vaginal delivery (IVD) only for failure to progress (FtP) before 45 min of pushing (group B). Primary outcome was postpartum hemorrhage (PPH). Maternal and neonatal outcomes associated with ASS ≥ 45 min were assessed with multivariable logistic regression models.

RESULTS

Prolonged ASS ≥45 min (group A, N=177) was associated with lower rate of persistent occiput posterior position (1.7 vs 9.5%, p<0.01) and of non-engaged presentation when expulsive efforts started (10.7 vs 27.4%, p<0.01), compared to IVD for FtP <45 min (group B, N=84). In group A, 52% of women had instrumental delivery. Prolonged active second stage was independently associated with lower odds of episiotomy (38.4 vs 61.9%, AOR(95%CI)=0.43[0.24-0.78]) and was not associated with PPH (5.1 vs 5.9%, AOR=1.01[0.28-3.68]), pH<7.20, 5-min Apgar score < 7 (20.2 vs 15.9%, AOR=2.00[0.89-4.48]), lactates > 6 (23.0 vs 24.3, AOR=1.45[0.68-3.07]) or transfer to neonatal intensive care unit (6.2 vs 2.4%, AOR=4.71[0.76-29.08].

DISCUSSION

Extending the duration of active second stage of labor beyond 45 min seems reasonable under rigorous surveillance of maternal and fetal wellbeing.

Clinical evaluation of labor: an evidence- and experience-based approach

During labor mother and fetus are evaluated at intervals to assess their well-being and determine how the labor is progressing. These assessments require skillful physical diagnosis and the ability to translate the acquired information into meaningful prognostic decision-making. We describe a coordinated approach to the assessment of labor. Graphing of serial measurements of cervical dilatation and fetal station creates "labor curves," which provide diagnostic and prognostic information. Based on these curves we recognize nine discrete labor abnormalities. Many may be related to insufficient or disordered contractile mechanisms. Several factors are strongly associated with development of labor disorders, including cephalopelvic disproportion, excess analgesia, fetal malpositions, intrauterine infection, and maternal obesity. Clinical cephalopelvimetry involves assessing pelvic traits and predicting their effects on labor. These observations must be integrated with information derived from the labor curves. Exogenous oxytocin is widely used. It has a high therapeutic index, but is easily misused. Oxytocin treatment should be restricted to situations in which its potential benefits clearly outweigh its risks. This requires there be a documented labor dysfunction or a legitimate medical reason to shorten the labor. Normal labor and delivery pose little risk to a healthy fetus; but dysfunctional labors, especially if stimulated excessively by oxytocin or terminated by complex operative vaginal delivery, have the potential for considerable harm. Conscientiously implemented, the approach to the evaluation of labor outlined in this review will result in a reasonable cesarean rate and minimize risks that may accrue from the labor and delivery process.

Obesity, Second Stage Duration, and Labor Outcomes in Nulliparous Women

OBJECTIVE

This study aimed to estimate second stage duration and its effects on labor outcomes in obese versus nonobese nulliparous women.

STUDY DESIGN

This was a secondary analysis of a cohort of nulliparous women who presented for labor at term and reached complete cervical dilation. Adjusted relative risks (aRR) were used to estimate the association between obesity and second stage characteristics, composite neonatal morbidity, and composite maternal morbidity. Effect modification of prolonged second stage on the association between obesity and morbidity was assessed by including an interaction term in the regression model.

RESULTS

Compared with nonobese, obese women were more likely to have a prolonged second stage (aRR: 1.48, 95% CI: 1.18-1.85 for ≥3 hours; aRR: 1.65, 95% CI: 1.18-2.30 for ≥4 hours). Obesity was associated with a higher rate of second stage cesarean (aRR: 1.78, 95% CI: 1.34-2.34) and cesarean delivery for fetal distress (aRR: 2.67, 95% CI: 1.18-3.58). Obesity was also associated with increased rates of neonatal (aRR: 1.38, 95% CI: 1.05-1.80), but not maternal morbidity (aRR: 1.06, 95% CI: 0.90-1.25). Neonatal morbidity risk was not modified by prolonged second stage.

CONCLUSION

Obesity is associated with increased risk of neonatal morbidity, which is not modified by prolonged second stage of labor.

Risks associated with cesarean delivery during prolonged second stage of labor

BACKGROUND

Data regarding maternal and fetal morbidities are limited to surgical morbidity per each additional hour in the second stage of labor.

OBJECTIVE

This study aimed to quantify perinatal morbidities associated with cesarean delivery by duration of the second stage of labor.

STUDY DESIGN

Our work is a retrospective cohort study of cesarean deliveries during the second stage of labor using the Consortium on Safe Labor database. All term, singleton pregnancies in cephalic presentation were included. Women with stillbirth or contraindications to vaginal delivery were excluded. Groups were divided by duration of the second stage of labor: ≤3 hours, 3-4 hours, 4-5 hours, 5-6 hours, and >6 hours. The primary outcome was a composite of maternal morbidities. The secondary outcomes were a composite of neonatal morbidities and individual maternal and neonatal morbidities. Baseline demographic and clinical characteristics were compared among groups. Univariate and multivariate analyses were performed.

RESULTS

We included 6273 women in total. In addition, 3652 women (58.2%) went through the second stage for ≤3 hours, 854 (13.6%) for 3 to 4 hours, 618 (9.9%) for 4 to 5 hours, 397 (6.3%) for 5 to 6 hours, and 752 (12.0%) for >6 hours. Neither the maternal nor neonatal morbidity composite outcomes were statistically different among the groups. Extended maternal length of stay (>5 days), increased birthweight, and lower rates of general anesthesia were associated with an increased duration of the second stage of labor. Chorioamnionitis, wound complications, postpartum hemorrhage, and thrombosis did not increase over time.

CONCLUSION

Women should be counseled regarding the duration of the second stage of labor, which should include a discussion of the risks associated with a cesarean delivery with a prolonged second stage of labor. However, these risks may not be as high as anticipated.

Relationship Between Prolonged Second Stage of Labor and Short-Term Neonatal Morbidity: A Systematic Review and Meta-Analysis

To evaluate the association between prolonged second stage of labor and the risk of adverse neonatal outcomes with a systematic review and meta-analysis. PubMed, Scopus and EMBASE were searched using the search strategy "Labor Stage, Second" AND (length OR duration OR prolonged OR abnormal OR excessive). Observational studies that examine the relationship between prolonged second stage of labor and neonatal outcomes were selected. Prolonged second stage of labor was defined as 4 h or more in nulliparous women and 3 h or more in multiparous women. The main neonatal outcomes were 5 min Apgar score <7, admission to the Neonatal Intensive Care Unit, neonatal sepsis and neonatal death. Data collection and quality assessment were carried out independently by the three reviewers. Twelve studies were selected including 266,479 women. In nulliparous women, a second stage duration greater than 4 h increased the risk of 5 min Apgar score <7, admission to the Neonatal Intensive Care Unit and neonatal sepsis and intubation. In multiparous women, a second stage of labor greater than 3 h was related to 5 min Apgar score <7, admission to the Neonatal Intensive Care Unit, meconium staining and composite neonatal morbidity. Prolonged second stage of labor increased the risk of 5 min Apgar score <7 and admission to the Neonatal Intensive Care Unit in nulliparous and multiparous women, without increasing the risk of neonatal death. This review demonstrates that prolonged second stage of labor increases the risk of neonatal complications in nulliparous and multiparous women.

Intrapartum ultrasound at the initiation of the active second stage of labor predicts spontaneous vaginal delivery

BACKGROUND

Longer duration of active pushing during labor is associated with a higher rate of operative delivery and an increased risk of maternal and neonatal complications. Although immediate pushing at complete dilatation is associated with lower rates of chorioamnionitis and postpartum hemorrhage, it is also associated with a longer duration of pushing.

OBJECTIVE

This study aimed to evaluate whether fetal head station and position, as assessed by ultrasound at the beginning of the pushing process, can predict the mode of delivery and duration of pushing in nulliparous women.

STUDY DESIGN

This prospective observational study included nulliparous women with neuraxial analgesia and complete cervical dilatation. The following sonographic parameters were assessed just before the beginning of the pushing process, at rest, and while pushing during contraction: head position, angle of progression, head-perineum distance, and head-symphysis distance. The change between rest and pushing was designated as delta angle of progression, delta head-perineum distance, and delta head-symphysis distance. The sonographic measurements and fetal head station assessed by vaginal examination were compared between women who had a spontaneous vaginal delivery to those who underwent an operative delivery, and between those who pushed for more or less than 1 hour.

RESULTS

Of the 197 women included in this study, 166 (84.3%) had a spontaneous vaginal delivery, 31 (15.7%) had an operative delivery, 23 (11.6%) had a vacuum delivery, and 8 (4.0%) had a cesarean delivery. Spontaneous vaginal delivery and shorter duration of pushing (less than an hour) were significantly more common with a nonocciput posterior position (10.6% vs 47.3%; P<.005), a wider angle of progression, a shorter head-perineum distance and head-symphysis distance (both during rest and while pushing), and a lower fetal head station as assessed by digital vaginal examination. However, a logistic regression model revealed that only the angle of progression at rest and the delta angle of progression were independently associated with a spontaneous vaginal delivery with an area under the curve of 0.82 (95% confidence interval, 0.76-0.87; P<.0001) and 0.75 (95% confidence interval, 0.67-0.79; P<.0001), respectively.

CONCLUSION

Ultrasound performed at the beginning of the active second stage of labor can assist in predicting the mode of delivery and duration of pushing and perform better than the traditional digital examination, with the angle of progression at rest and delta angle of progression being the best predictors.

Perinatal Outcomes with Longer Second Stage of Labor: A Risk Analysis Comparing Expectant Management to Operative Intervention

OBJECTIVE

The aim of this study is to assess the impact of a prolonged second stage of labor on maternal and neonatal outcomes by comparing women who had expectant management versus operative intervention beyond specified timeframes in the second stage of labor.

STUDY DESIGN

Retrospective cohort including live singletons at ≥36 weeks who reached the second stage of labor. Expectant management (second stage >3, 2, 2, and 1 hour in nulliparas with an epidural, nulliparas without an epidural, multiparas with an epidural, and multiparas without an epidural, respectively) was compared with those who had an operative delivery (vaginal or cesarean) prior to these timeframes. The primary maternal outcome was a composite of postpartum hemorrhage, chorioamnionitis, operative complications, postpartum infections, and intensive care unit admission. The primary neonatal outcome was a composite of cord blood acidemia, 5-minute Apgar's score <5, chest compressions or intubation at birth, sepsis, seizures, birth injury, death, transfer to a long-term care facility, and respiratory support for >1 day.

RESULTS

Among 218 women, 115 (52.8%) had expectant management. Expectant management was associated with a significantly increased risk of the maternal composite (adjusted odds ratio [aOR]: 1.99, 95% confidence interval [CI]: 1.09-3.64) but not the neonatal composite (aOR: 1.54, 95% CI: 0.71-3.35).

CONCLUSION

Expectant management of a prolonged second stage was associated with a higher rate of adverse maternal outcomes, but the rate of adverse neonatal outcomes was not significantly increased.

Extending the second stage of labor in nulliparous women with epidural analgesia: a cost-effectiveness analysis

The objective of this study was to evaluate maternal outcomes with an extended second stage of labor and determine if an extended second stage is cost effective. This theoretical model evaluated expectant management to 4 h compared to delivery at 3 h in the setting of a prolonged second stage of labor in nulliparous women with epidural analgesia. In our theoretical cohort of 165,000 women, we found that an extended second stage resulted in 53,268 more spontaneous vaginal deliveries, 14,163 fewer operative vaginal deliveries, and 39,105 fewer cesarean deliveries. This approach also resulted in 1 fewer instance of maternal death. An extended second stage, however, led to 14,025 more cases of chorioamnionitis, 1699 more episodes of postpartum hemorrhage requiring transfusion, and 119 more severe perineal lacerations, suggesting that while an extended second stage of labor results in overall improved maternal outcomes, there are tradeoffs. Expectant management to 4 h was the dominant strategy in the model, as it saved over $114 million US dollars and resulted in 4000 additional QALYs over our theoretical cohort. Sensitivity analysis indicated that expectant management until 4 h was cost-effective as long as the probability of cesarean delivery at 4 h was below 41.8%, and was the dominant strategy below 38.2% (baseline input: 19.5%). Multivariable sensitivity analysis demonstrated that the model was robust over a wide range of assumptions. Expectant management of the second stage of labor until 4 h is a cost-effective strategy to prevent primary cesarean deliveries, decrease costs, and improve some maternal outcomes, despite tradeoffs.

Association Between Time of Day and the Decision for an Intrapartum Cesarean Delivery

OBJECTIVE

To examine whether the decision and indications for performing intrapartum cesarean delivery vary by time of day.

METHODS

We conducted a secondary analysis of a multicenter observational cohort of 115,502 deliveries (2008-2011), including nulliparous women with term, singleton, nonanomalous live gestations in vertex presentation who were attempting labor. Those who attempted home birth, or underwent cesarean delivery scheduled or decided less than 30 minutes after admission were excluded. Time of day was defined as cesarean delivery decision time among those who delivered by cesarean and delivery time among those who delivered vaginally, categorized by each hour of a 24-hour day. Primary outcomes were decision to perform cesarean delivery and the indications for cesarean delivery (labor dystocia, nonreassuring fetal status, or other indications). Secondary outcomes included whether a dystocia indication adhered to standards promoted to reduce cesarean delivery rates. Bivariate analyses were performed using χ and Kruskal-Wallis tests for categorical and continuous outcomes, respectively, and generalized additive models with smoothing splines explored nonlinear associations without adjustment for other factors.

RESULTS

Seven thousand nine hundred fifty-six (22.1%) of 36,014 eligible women underwent cesarean delivery. Decision for cesarean delivery (P<.001) decreased from midnight (21.2%) to morning, reaching a nadir at 10:00 (17.9%) and subsequently rising to peak at 21:00 (26.2%). The frequency of cesarean delivery for dystocia also was significantly associated with time of day (P<.001) in a pattern mirroring overall cesarean delivery. Among cesarean deliveries for dystocia (n=5,274), decision for cesarean delivery at less than 5 cm dilation (P<.001), median duration from 5 cm dilation to cesarean delivery decision (P=.003), and median duration from complete dilation to cesarean delivery decision (P=.014) all significantly differed with time of day. The frequency of nonreassuring fetal status and "other" indications were not significantly associated with time of day (P>.05).

CONCLUSION

Among nulliparous women who were attempting labor at term, the decision to perform cesarean delivery, particularly for dystocia, varied with time of day. Some of these differences correlate with labor management differences, given the changing frequency of latent phase cesarean delivery and median time in active phase.

Does programmed intermittent epidural bolus improve childbirth conditions of nulliparous women compared with patient-controlled epidural analgesia?: A multicentre, randomised, controlled, triple-blind study

BACKGROUND

Epidural analgesia may change the mechanics of childbirth. These changes are related to the concentration of the local anaesthetic used epidurally but probably also to its mode of delivery into the epidural space.

OBJECTIVE

To determine whether the administration of programmed intermittent epidural boluses (PIEB) improves the mechanics of second-stage labour compared with patient-controlled epidural analgesia (PCEA) with a background infusion.

DESIGN

A randomised, controlled, triple-blind study.

SETTING

Multicentre study including four level III maternity units, January 2014 until June 2016.

PATIENTS

A total of 298 nulliparous patients in spontaneous labour were randomised to a PIEB or PCEA group.

INTERVENTION

After epidural initiation with 15 ml of 0.1% levobupivacaine containing 10 μg of sufentanil, patients received either an hourly bolus of 8 ml (PIEB) or a continuous rate infusion of 8 ml h (PCEA): the drug mixture used was levobupivacaine 0.1% and sufentanil 0.36 μg ml.

MAIN OUTCOME MEASURES

The primary outcome was a composite endpoint of objective labour events: a posterior occiput position in the second stage, an occiput position at birth, waiting time at full cervical dilatation before active maternal pushing more than 3 h, maternal active pushing duration more than 40 min, and foetal heart rate alterations. Vaginal instrumental delivery rates, analgesia and motor blockade scores were also recorded.

RESULTS

From the 298 patients randomised, data from 249 (124 PIEB, 125 PCEA) were analysed. No difference was found in the primary outcome: 48.0% (PIEB) and 45.5% (PCEA) of patients, P = 0.70. In addition, no difference was observed between the groups for each of the individual events of the composite endpoint, nor in the instrumental vaginal delivery rate, nor in the degree of motor blockade. Despite an equivalent volume of medication in the groups, a significantly higher analgesia score at full dilatation was observed in the PIEB group, odds-ratio = 1.9 (95% confidence interval, 1.0 to 3.5), P = 0.04.

CONCLUSION

The mechanics of the second stage did not differ whether PIEB or PCEA was used. Analgesic conditions appeared to be superior with PIEB, especially at full dilation.

TRIAL REGISTRATION

NCT01856166.

Effects of flexible sacrum positions during the second stage of labour on maternal and neonatal outcomes: A systematic review and meta-analysis

AIMS AND OBJECTIVES

To assess the effects of flexible sacrum positions on mode of delivery, duration of the second stage of labour, perineal trauma, postpartum haemorrhage, maternal pain, abnormal foetal heart rate patterns and Apgar scores based on published literature.

BACKGROUND

Maternal positions served as a nonmedical intervention may facilitate optimal maternal and neonatal outcomes during labour. Flexible sacrum positions are conducive to expanding pelvic outlet. Whether flexible sacrum positions have positive effects on maternal and neonatal well-being is a controversial issue under heated discussion.

DESIGN

We performed a systematic review and meta-analysis based on PRISMA guidelines.

METHODS

Randomised controlled trials (RCTs) comparing any flexible sacrum position with non-flexible sacrum position in the second stage of labour were included. PubMed, EMBASE, Cochrane Library, CINAHL, CNKI (China National Knowledge Infrastructure), SinoMed and Wanfang databases were searched from inception to 11 March 2019 for published RCTs. Risk of bias was assessed by the Cochrane criteria, and random-effects meta-analyses were conducted by RevMan 5.3.

RESULTS

Sixteen studies (3,397 women) published in English were included. Flexible sacrum positions in the second stage of labour could reduce the incidence of operative delivery, instrumental vaginal delivery, caesarean section, episiotomy, severe perineal trauma, severe pain and shorten the duration of active pushing phase in the second stage of labour. However, flexible sacrum positions may increase the incidence of mild perineal trauma. There was no significant difference in the duration of the second stage of labour, maternal satisfaction and other outcomes.

CONCLUSIONS

Flexible sacrum positions are superior in promoting maternal well-being during childbirth. However, several results require careful interpretation. More rigorous original studies are needed to further explore their effects.

RELEVANCE TO CLINICAL PRACTICE

The results support the use of flexible sacrum positions. Flexible sacrum positions are recommended to apply flexibly or tailor to individual woman's labour progress.

Maternal and neonatal outcomes following a prolonged second stage of labor: A meta-analysis of observational studies

Several articles investigated the impact of prolonged second stage of labor on maternal and neonatal outcomes; however, strict consensus is still lacking. The purpose of the present meta-analysis is to investigate risk factors that contribute to the pathophysiology of prolonged labor as well as effect sizes of maternal and neonatal morbidity. We searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar database. Observational studies (prospective and retrospective) were considered eligible for inclusion in the present meta-analysis. To minimize the possibility of article losses we avoided language, country and date restrictions. Meta-analysis was performed with the RevMan 5.3 and secondary analysis with Rstudio. Overall, 13 studies were included in the present systematic review that comprised 337.845 parturient. Prolonged second stage was associated with higher odds of postpartum hemorrhage, chorioamnionitis, endometritis, postpartum fever and obstetric anal sphincter injury. Persistent occiput posterior position and shoulder dystocia were also more prevalent compared to women with normal duration of the second stage. The need for admission to the neonatal intensive care unit was higher as well as the risk of developing neonatal sepsis. On the other hand, the odds of perinatal death were comparable among cases with prolonged and normal duration of the second stage. The results of the present meta-analysis clearly indicate that deliveries following a prolonged second stage of labor are at increased risk of maternal and neonatal complications. The presented effect estimates can be used in current clinical practice during patient counseling.

Adverse effect of delayed pushing on postpartum blood loss in nulliparous women with epidural analgesia

OBJECTIVE

To test for an association between blood loss and time until pushing (TUP) after full cervical dilation in nulliparous women with epidural analgesia.

METHODS

A prospective cohort study was performed at the University Hospital of Zurich between October 2015 and November 2016. Included were 228 nulliparous women with singleton pregnancy, planned vaginal delivery after 36 completed weeks of gestation, epidural analgesia, and guided active pushing. TUP was defined as the interval between full cervical dilation and initiation of active pushing. The primary outcome measure was blood loss, assessed by the postpartum decrease in hemoglobin (ΔHb), estimated blood loss, and rate of ΔHb ≥30 g/L. Associations between TUP and primary and secondary maternal and neonatal delivery outcomes were assessed using Spearman correlation, Mann-Whitney U test, Kruskal-Wallis test, or Fisher exact test, as appropriate.

RESULTS

Longer TUP correlated significantly with increased ΔHb (ρ=0.142, P=0.033) and higher rates of ΔHb ≥30 g/l (P=0.002). Composite adverse maternal and neonatal outcomes were unaffected.

CONCLUSION

On the grounds of increased maternal blood loss, and in contrast to the current International Federation of Gynecology and Obstetrics (FIGO) guideline, delayed active pushing is not recommended in nulliparous women with epidural analgesia.

Evidence-based management of the second stage of labor

The second stage of labor is defined as the time from complete dilation of the cervix to delivery of the fetus. The objective of this seminar is to provide a contemporary, evidence-based approach to management of the second stage of labor. This seminar reviews background maternal and fetal characteristics that impact the duration of the second stage of labor, the recommended evidence-based management (e.g. immediate pushing, manual rotation, operative vaginal delivery), and the maternal/neonatal morbidity clinicians must consider when deciding between operative delivery and a prolonged second stage of labor.

Second-stage labor: consensus versus science

There has been a recent significant evolution in suggested practices for the management of labor because of the increased national cesarean delivery rate. One of the most significant changes was promulgated by the 2014 Obstetric Care Consensus entitled, "Safe Prevention of Primary Cesarean Delivery," which recommended reconsideration of the upper limits of the length of labor in the second stage as well as the first stage. We previously published a 2016 Clinical Opinion challenging the second-stage practice change. Over the past 2 years, there have been at least 5 reports as well as 2 national organization statements supporting revised management of second-stage labor. We now revisit the second-stage issue because we believe that it is important to carefully clarify the current status resulting from consensus statements as well as the evolving current status of scientific evidence. We structured this Clinical Opinion using questions in an effort to chronicle the story of how obstetric precepts on second-stage labor in use for more than 50 years were being replaced. How did we get here? What is the current evidence? What can be learned from this experience? Should American obstetrics now "fall back" to pre-existing obstetric precepts for the management of second-stage labor after having "sprung forward" an additional hour-namely, lengthening the duration of acceptable second-stage labor to 4 hours as recommended by the Obstetric Care Consensus? We believe that the data published since our 2016 Clinical Opinion buttress our original position that prolongation of the second stage beyond historical precepts is unsafe.

Maternal risk factors for adverse outcome in asphyxiated newborns treated with hypothermia: parity and labor duration matter

Introduction: Perinatal asphyxia remains a frequent cause of neonatal mortality and long-term neurodevelopmental sequelae, despite the introduction of therapeutic hypothermia. Specific maternal characteristics may predispose asphyxiated newborns treated with hypothermia to worse outcome.Objective: To investigate the possible association between specific maternal factors and adverse outcome in asphyxiated newborns treated with hypothermia.Methods: We conducted a retrospective review of our database of 215 asphyxiated newborns treated with hypothermia from 2008 to 2015. We collected maternal characteristics including parity and labor duration, and we defined adverse outcome as death and/or brain injury. We compared the maternal characteristics between the asphyxiated newborns who developed adverse outcome and those who did not.Results: Asphyxiated newborns born to nulliparous mothers had a significantly higher risk of adverse outcome (61%), compared to asphyxiated newborns born from primiparous (19%) and multiparous (20%) mothers (p = .002). Labor duration was longer in nulliparous mothers (p = .04). Among mothers who delivered vaginally, labor duration was significantly longer in newborns developing adverse outcome (p = .04). In multivariable analysis, parity was confirmed as an independent predictor of adverse outcome in all newborns, but labor duration showed a borderline non-significant association with adverse outcome (p = .051) only in newborns born vaginally. Labor duration beyond 12 h of life was associated with maximal sensitivity and specificity in detecting asphyxiated newborns at an increased risk of adverse outcome despite hypothermia treatment (AUC 0.62, p = .044).Conclusions: Newborns with evidence of perinatal asphyxia, born to nulliparous mothers, and especially to those in whom the duration of labor has been prolonged, might be at higher risk of death or brain injury despite the use of therapeutic hypothermia.

Prediction of spontaneous vaginal delivery in nulliparous women with a prolonged second stage of labor: the value of intrapartum ultrasound

BACKGROUND

A limited number of studies have addressed the role of intrapartum ultrasound in the prediction of the mode of delivery in women with prolonged second stage of labor.

OBJECTIVE

The objective of the study was to evaluate the role of transabdominal and transperineal sonographic findings in the prediction of spontaneous vaginal delivery among nulliparous women with prolonged second stage of labor.

STUDY DESIGN

This was a 2-center prospective study conducted at 2 tertiary maternity units. Nulliparous women with a prolonged active second stage of labor, as defined by active pushing lasting more than 120 minutes, were eligible for inclusion. Transabdominal ultrasound to evaluate the fetal head position and transperineal ultrasound for the measurement of the midline angle, the head-perineum distance, and the head-symphysis distance were performed in between uterine contractions and maternal pushes. At transperineal ultrasound the angle of progression was measured at rest and at the peak of maternal pushing effort. The delta angle of progression was defined as the difference between the angle of progression measured during active pushing at the peak of maternal effort and the angle of progression at rest. The sonographic findings of women who had spontaneous vaginal delivery vs those who required obstetric intervention, either vacuum extraction or cesarean delivery, were evaluated and compared.

RESULTS

Overall, 109 were women included. Spontaneous vaginal delivery and obstetric intervention were recorded in 40 (36.7%) and 69 (63.3%) patients, respectively. Spontaneous vaginal delivery was associated with a higher rate of occiput anterior position (90% vs 53.2%, P < .0001), lower head-perineum distance and head-symphysis distance (33.2 ± 7.8 mm vs 40.1 ± 9.5 mm, P = .001, and 13.1 ± 4.6 mm vs 19.5 ± 8.4 mm, P < .001, respectively), narrower midline angle (29.6° ± 15.3° vs 54.2° ± 23.6°, P < .001) and wider angle of progression at the acme of the pushing effort (153.3° ± 19.8° vs 141.8° ± 25.7°, P = .02) and delta-angle of progression (17.3° ± 12.9° vs 12.5° ± 11.0°, P = .04). At logistic regression analysis, only the midline angle and the head-symphysis distance proved to be independent predictors of spontaneous vaginal delivery. More specifically, the area under the curve for the prediction of spontaneous vaginal delivery was 0.80, 95% confidence interval (0.69-0.92), P < .001, and 0.74, 95% confidence interval (0.65-0.83), P = .002, for the midline angle and for the head-symphysis distance, respectively.

CONCLUSION

Transabdominal and transperineal intrapartum ultrasound parameters can predict the likelihood of spontaneous vaginal delivery in nulliparous women with prolonged second stage of labor.

Defining the upper limit of the second stage of labor in nulliparous patients

BACKGROUND

Increased duration of the second stage of labor provides clinical challenges in decision-making regarding the optimal mode of delivery that minimizes maternal and neonatal morbidity.

OBJECTIVE

In a large cohort of uncomplicated nulliparous singleton cephalic labors, we sought to examine the effect of increasing duration of second stage on delivery and perinatal outcome.

STUDY DESIGN

The GENESIS Study recruited 2336 nulliparous patients with vertex presentation in a prospective double-blinded study to examine prenatal and intrapartum predictors of delivery. Metrics included maternal demographics, duration of second stage, mode of delivery, and associated maternal and neonatal outcomes. Indicators of morbidity included third- or fourth-degree tear, postpartum hemorrhage, neonatal intensive care unit admission, low Apgar scores, cord pH <7.20 and a composite of birth injury that included cephalohematoma, fetal laceration, brachial plexus palsy, facial nerve palsy, and fetal fracture.

RESULTS

Of 2336 recruited nulliparous participants, 1872 reached the second stage of labor and had complete data for analysis. Increased maternal age (P=.02) and birthweight (P<.001) were found to be associated with a longer second stage. Increasing second stage duration was found to impact on mode of delivery, such that at <1 hour duration the spontaneous vaginal delivery rate was 63% vs 24% at >3 hours (P<.001). Operative vaginal delivery increased from 35% at <1 hour to 65% at >3 hours (P<.001). The rate of cesarean delivery increased with duration of the second stage from 1.2% at <1 hour to 11% at >3 hours (P<.001). The rates of third- or fourth-degree tear increased with second stage duration (P=.003), as did postpartum hemorrhage (P<.001). The composite neonatal birth injury rate increased from 1.8% at <1 hour to 3.4% at >3 hours. The maximum rate of birth injury was 6.5% at 2-3 hours (P<.001). Multiple logistic regression analysis that controlled for maternal age and birthweight confirmed that operative vaginal delivery, perineal trauma, postpartum hemorrhage, and neonatal birth injury remained significantly more likely with increasing second stage duration.

CONCLUSION

In a prospective cohort of nulliparous pregnancies, increasing duration of second stage of labor was associated with increased rates of operative vaginal and cesarean delivery. Although almost 90% of term nulliparous women with a second stage of labor >3 hours will succeed in achieving a vaginal birth, this success comes at a maternal morbidity cost, with a 10% risk of severe perineal injury and an increasing rate of significant neonatal injury.

Duration of labor and maternal and neonatal morbidity

BACKGROUND

Labor dystocia has been identified as a contributor to the rising cesarean delivery rate in the United States. Allowing more time for vaginal delivery, while being cognizant of maternal and neonatal outcomes, has been identified as a possible strategy to lower cesarean delivery rates.

OBJECTIVE

This study aimed to characterize the relationship between the duration of active phase and second-stage labor and maternal and neonatal morbidity.

STUDY DESIGN

We present a secondary analysis of the Consortium on Safe Labor project. From labors of 66,940 nonanomalous nulliparous term singleton vertex gestations, we excluded labors for which active phase (≥6 cm dilation) or second stage durations could not be calculated and from sites that did not report determinants of morbidity. For each duration of active phase or second stage labor (grouped in 1-hour increments), the adjusted maternal and neonatal composite morbidity was estimated by and compared with the morbidity associated with a duration <1 hour total and a duration of 1 hour shorter.

RESULTS

After exclusions, 48,144 deliveries remained. In adjusted models, compared with labor durations <1 hour total, maternal composite morbidity was significantly higher across active phase and second stage durations (both P<.001); neonatal composite morbidity was higher across the second stage (P<.001), but not active phase (P=.07) duration. These relationships appear linear with no apparent inflection point, and morbidity increases more rapidly. When compared with labor durations 1 hour shorter, significant differences persisted in maternal and neonatal composite morbidity in second stage labor only through 4 and 3 hours, respectively.

CONCLUSION

Maternal and neonatal composite morbidity is greater with longer durations of active and second stage labor; however, no clear cutoff point was determined to suggest truncation of either stage of labor for reasons of morbidity. In addition, incrementally higher morbidities that were noted vs duration <1 hour total were obscured when comparison was made with labors 1 hour shorter, which suggests that focusing on short differences in duration of labor may mask important underlying trends.

Second-Stage Duration and Outcomes Among Women Who Labored After a Prior Cesarean Delivery

OBJECTIVE

To characterize probabilities of vaginal delivery based on second-stage duration along with maternal and neonatal risks for women undergoing labor after cesarean delivery.

METHODS

This unplanned secondary analysis of the Maternal-Fetal Medicine Units Cesarean Registry, a prospective observational cohort, assessed outcomes in women with a prior uterine scar and included women with a previous cesarean delivery without prior vaginal delivery who reached the second stage of labor. The primary outcome was mode of delivery by second-stage duration. Secondary outcomes included assessment of individual adverse maternal (chorioamnionitis, atony, endometritis, hysterectomy, uterine rupture or dehiscence, and red cell transfusion) and neonatal (cord pH less than 7.10, Apgar score less than 6 at 5 minutes, neonatal intensive care unit admission, and ventilatory support) outcomes.

RESULTS

Of 4,579 women with a previous cesarean delivery who reached the second stage of labor, 4,147 (90.6%) delivered vaginally. As second stage increased, successful vaginal delivery rates decreased: 97.3% at less than 1 hour (95% CI 96.6-97.9%), 91.5% at 1 to less than 2 hours (95% CI 89.8-93.1%), 78.5% at 2 to less than 3 hours (95% CI 74.5-82.1%), 62.3% at 3 to less than 4 hours (95% CI 55.2-69.1%), and 45.6% at 4 hours or greater (95% CI 37.7-53.7%). Risk of all adverse maternal outcomes increased with the length of the second stage. Specifically, risk of uterine rupture or dehiscence increased with second-stage length from less than 1 hour (0.7%), 1 to less than 2 hours (1.4%), 2 to less than 3 hours (1.5%), to 3 hours or greater (3.1%) (P<.001 for differential risk across the second stage). Risk of neonatal outcomes did not differ significantly by second-stage length.

CONCLUSION

Although many women with a longer second stage (greater than 3 hours) will achieve successful vaginal delivery, these patients may be at increased risk for adverse maternal outcomes and should have close observation of fetal heart rate monitoring, maternal vital signs, and symptoms suggestive of uterine rupture or dehiscence.

Relationship between the Duration of the Second Stage of Labour and Neonatal Morbidity

(1) Background: To assess the relationship between the duration of the second stage of labour and the neonatal morbidity risk; (2) Methods: An observational, analytical, retrospective cohort study was performed at the "Mancha-Centro" Hospital (Spain) during the 2013⁻2016 period. Data were collected from 3863 women who gave a vaginal birth. The studied neonatal morbidity variables were umbilical cord arterial pH, 5-min Apgar score, need for advanced neonatal resuscitation, and a composite neonatal morbidity variable on which the multivariate analysis was done. A univariate analysis was used for the potential risk factors and a multivariate analysis with binary logistic regression to control for possible confounding factors; (3) Results: The univariate analysis showed a statistically significant relationship between the duration of the second stage of labour and a high risk of advanced neonatal resuscitation and composite neonatal morbidity in multiparous women. However, after performing the multivariate analysis for the variable "composite neonatal morbidity", we observed no relationship with the duration of the second stage of labour in either nulliparous or multiparous women; (4) Conclusions: The duration of the second stage of labour was not related to an increased risk of neonatal morbidity in our study population.

The impact of extending the second stage of labor to prevent primary cesarean delivery on maternal and neonatal outcomes

BACKGROUND

A low rate of primary cesarean delivery is expected to reduce some of the major complications that are associated with a repeat cesarean delivery, such as uterine rupture, adhesive placental disorders, hysterectomy, and even maternal death. Since 2014, and in alignment with the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine, we changed our approach to labor dystocia, defined as abnormal progression of labor, by allowing a longer duration of the second stage of labor.

OBJECTIVE

To examine the effect of prolonging the second stage of labor on the rate of cesarean delivery, and maternal and neonatal outcomes.

MATERIALS AND METHODS

In a historical control group, we compared maternal and neonatal outcomes over 2 periods. Period I (9300 patients): from May 2011 until April 2014, when a prolonged second stage in nulliparous women was considered after 3 hours with regional anesthesia or 2 hours if no such anesthesia was provided. Second-stage arrest was defined in multiparous women after 2 hours with regional anesthesia or 1 hour without it. Period II (10,531 patients): from May 2014 until April 2017, allowed nulliparous and multiparous women continuing the second stage of labor an additional 1 hour before diagnosing second-stage arrest. Singleton deliveries at or beyond 37 weeks' gestation were initially considered for eligibility. We excluded women with high-risk pregnancies and known fetal anomalies. For comparing means, we used the t test. If variables were not normally distributed, we used the Mann-Whitney test instead. For comparing proportions, we used the χ² test with continuity correction.

RESULTS

The primary cesarean delivery was decreased in nulliparous women from 23.3% (819 of 3515) in period I to 15.7% (596 of 3796) in period II (relative risk [RR], 0.67; 95% CI, 0.61-0.74), a trend that was also significant in multiparous women (10.9%, 623 of 5785, in period I vs 8.1%, 544 of 6735, in period II; RR, 0.75; 95% CI, 0.67-0.84). The rate of operative vaginal deliveries in nulliparous women was higher in period II than in period I (19.2%, 732 of 3515, vs 17.7%, 622 of 3796, P < .0001). Rates of third- and fourth-degree laceration and of shoulder dystocia were also higher in period II. The rate of arterial cord pH < 7.0 and the rate of admission to the neonatal intensive care unit were higher in period II, but the early neurological outcome was not different when comparing the 2 periods.

CONCLUSION

The new policy of labor management successfully decreased primary cesarean deliveries, with a small rise in instrumental deliveries. However, it also increased the other immediate maternal and neonatal complications. A higher rate of lower umbilical artery cord pH was the most significant finding; however, the early neurological outcome did not change. It is possible that the ongoing adjustment to the new labor protocol will avoid, in the future, maternal and neonatal complications. The long-term maternal and neonatal consequences of our new approach will be evaluated in future studies.

A Review of the Impact of Obstetric Anesthesia on Maternal and Neonatal Outcomes

Obstetric anesthesia has evolved over the course of its history to encompass comprehensive aspects of maternal care, ranging from cesarean delivery anesthesia and labor analgesia to maternal resuscitation and patient safety. Anesthesiologists are concerned with maternal and neonatal outcomes, and with preventing and managing complications that may present during childbirth. The current review will focus on recent advances in obstetric anesthesia, including labor anesthesia and analgesia, cesarean delivery anesthesia and analgesia, the effects of maternal anesthesia on breastfeeding and fever, and maternal safety. The impact of these advances on maternal and neonatal outcomes is discussed. Past and future progress in this field will continue to have significant implications on the health of women and children.

[Which interventions during labour to decrease the risk of perineal tears? CNGOF Perineal Prevention and Protection in Obstetrics Guidelines]

OBJECTIVE

The objective of this review was to evaluate whether interventions performed during labour could influence the risk of perineal tears.

METHODS

A separate keyword search for each medical intervention during labor was performed by selecting only studies evaluating perineal consequences, particularly the risk of obstetrical anal sphincter injury (LOSA). Interventions during pregnancy and during fetal expulsion have been specifically addressed in other chapters of the recommendations.

RESULTS

Maternal mobilisation and postures during the first stage of labour have not been shown to reduce the risk of OASIS (LE3). No particular posture has demonstrated its superiority over any other during the second stage of labour for preventing obstetric perineal lesions including OASIS and postnatal incontinence (urinary or faecal) (LE2). There is no reason to recommend one maternal posture rather than another during the first and the second stages of labour for the purpose of reducing the risk of OASIS (Grade C). Women should be allowed to choose the position most comfortable for them during the first and second stages of labour (Professional consensus). Posterior cephalic positions present the greatest risks of perineal injury (LE2). Manual rotation of cephalic posterior positions to the anterior during the second stage of labour may make it possible to reduce the risk of operative vaginal delivery, although no reduction in the risk of perineal injuries or OASIS has been clearly demonstrated (LE3). For fetuses in posterior cephalic positions, no data justifies a preference for manual rotation at full dilation to diminish the risk of perineal injury (Professional consensus). Urinary catheterisation is recommended for women with epidural analgesia during labour when spontaneous micturition is not possible (Professional consensus). Although current data does not justify a preference for continuous or intermittent urinary catheterisation (LE2), intermittent catheterisation nonetheless appears preferable in this situation (Professional consensus). During the second stage phase, delayed pushing does not modify the risk of OASIS (LE1). It does, however, increase the chances of spontaneous delivery (LE1). It is thus recommended that, when maternal and fetal status allow it, the start of pushing should be delayed (Grade A). There is no evidence to support preferring one pushing technique rather than another to diminish the risk of OASIS (grade B). Performing an operative vaginal delivery for the sole purpose of reducing the duration of the second stage of labour may increase the risk of OASIS (LE3). Perineal massage or the application of warm compresses during the second stage of labour appear to reduce the risk of OASIS (LE2). However, we have not made a determination about their use in clinical practice.

Effect of Immediate vs Delayed Pushing on Rates of Spontaneous Vaginal Delivery Among Nulliparous Women Receiving Neuraxial Analgesia: A Randomized Clinical Trial

IMPORTANCE

It is unclear whether the timing of second stage pushing efforts affects spontaneous vaginal delivery rates and reduces morbidities.

OBJECTIVE

To evaluate whether immediate or delayed pushing results in higher rates of spontaneous vaginal delivery and lower rates of maternal and neonatal morbidities.

DESIGN, SETTING, AND PARTICIPANTS

Pragmatic randomized clinical trial of nulliparous women at or beyond 37 weeks' gestation admitted for spontaneous or induced labor with neuraxial analgesia between May 2014 and December 2017 at 6 US medical centers. The interim analysis suggested futility for the primary outcome and recruitment was terminated with 2414 of 3184 planned participants. Follow-up ended January 4, 2018.

INTERVENTIONS

Randomization occurred when participants reached complete cervical dilation. Immediate group participants (n = 1200) began pushing immediately. Delayed group participants (n = 1204) were instructed to wait 60 minutes.

MAIN OUTCOMES AND MEASURES

The primary outcome was spontaneous vaginal delivery. Secondary outcomes included total duration of the second stage, duration of active pushing, operative vaginal delivery, cesarean delivery, postpartum hemorrhage, chorioamnionitis, endometritis, perineal lacerations (≥second degree), and a composite outcome of neonatal morbidity that included neonatal death and 9 other adverse outcomes.

RESULTS

Among 2414 women randomized (mean age, 26.5 years), 2404 (99.6%) completed the trial. The rate of spontaneous vaginal delivery was 85.9% in the immediate group vs 86.5% in the delayed group, and was not significantly different (absolute difference, -0.6% [95% CI, -3.4% to 2.1%]; relative risk, 0.99 [95% CI, 0.96 to 1.03]). There was no significant difference in 5 of the 9 prespecified secondary outcomes reported, including the composite outcome of neonatal morbidity (7.3% for the immediate group vs 8.9% for the delayed group; between-group difference, -1.6% [95% CI, -3.8% to 0.5%]) and perineal lacerations (45.9% vs 46.4%, respectively; between-group difference, -0.4% [95% CI, -4.4% to 3.6%]). The immediate group had significantly shorter mean duration of the second stage compared with the delayed group (102.4 vs 134.2 minutes, respectively; mean difference, -31.8 minutes [95% CI, -36.7 to -26.9], P < .001), despite a significantly longer mean duration of active pushing (83.7 vs 74.5 minutes; mean difference, 9.2 minutes [95% CI, 5.8 to 12.6], P < .001), lower rates of chorioamnionitis (6.7% vs 9.1%; between-group difference, -2.5% [95% CI, -4.6% to -0.3%], P = .005), and fewer postpartum hemorrhages (2.3% vs 4.0%; between-group difference, -1.7% [95% CI, -3.1% to -0.4%], P = .03).

CONCLUSIONS AND RELEVANCE

Among nulliparous women receiving neuraxial anesthesia, the timing of second stage pushing efforts did not affect the rate of spontaneous vaginal delivery. These findings may help inform decisions about the preferred timing of second stage pushing efforts, when considered with other maternal and neonatal outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02137200.

The impact of analgesic intervention during the second stage of labour: a retrospective cohort study

PURPOSE

The incidence of epidural top-ups received in the second stage of labour in nulliparous women and the obstetrical and neonatal implications associated with these boluses are explored in this retrospective observational study. We hypothesized that an epidural top-up in the second stage of labour reduces operative deliveries by resolving inadequate analgesia.

METHODS

A population-based cohort analysis was performed using perinatal data from 1 January 2013 through 31 December 2014. An anesthesia database provided information to determine the top-up incidence. Women with or without a top-up for second-stage duration were compared for method of delivery and neonatal characteristics using descriptive statistics. Logistic regression identified predictive factors for method of delivery.

RESULTS

Of the 1,462 women with a second stage of labour > one hour who received epidural analgesia, 105 (7%) required a top-up during the second stage of labour. Women who received a top-up were more likely to have had induction of labour and/or augmentation (89% vs 76%; odds ratio [OR], 2.43; 95% confidence interval [CI], 1.32 to 4.49; P = 0.003), a longer second stage (303 min vs 171 min; mean difference, 132 min; 95% CI, 113 to 151; P < 0.001), and more assisted vaginal (41% vs 17%; OR, 3.35; 95% CI, 2.21 to 5.1; P < 0.001) or Cesarean deliveries (26% vs 11%; OR, 3.04; 95% CI, 1.91 to 4.8; P < 0.001) than women without a top-up.

CONCLUSION

Most women who received a top-up had a vaginal (spontaneous or assisted) delivery. Compared with women without a top-up, women requiring a top-up had more predictors of difficult labour and higher rates of assisted vaginal delivery and Cesarean delivery.

Relationship between duration of second stage of labour and postpartum anaemia

AIM

To assess the relationship between the duration of the second stage of labour and postpartum anaemia during vaginal birth.

METHODS

An observational, analytical retrospective cohort study was performed at the "Mancha-Centro Hospital" (Spain) during the 2013-2016 period. Data were collected from 3437 women who had a vaginal birth. Postpartum anaemia was defined as a haemoglobin level below 11g/dL at 24h postpartum. A univariate analysis was used for potential risk factors and a multivariate analysis with binary logistic regression to control for possible confounding factors.

FINDINGS

The incidence of postpartum anaemia was 42.0%. The risk of postpartum anaemia did not increase in nulliparous women whose duration of the second stage of labour exceeded 4h. Compared with multiparous women who delivered between 0 and 3h, multiparous women with a duration of the second stage of labour beyond 3h were at higher risk of postpartum anaemia (OR=2.43 [1.30-4.52]).

CONCLUSION

The duration of the second stage of labour beyond 4h is safe for postpartum anaemia in nulliparous women. However in multiparous women, monitoring should increase if the second stage of labour exceeds 3h given the increased risk of postpartum anaemia.

Racial and Ethnic Differences in Utilization of Labor Management Strategies Intended to Reduce Cesarean Delivery Rates

OBJECTIVE

To examine whether racial and ethnic differences exist in the frequency of and indications for cesarean delivery and to assess whether application of labor management strategies intended to reduce cesarean delivery rates is associated with patient's race and ethnicity.

METHODS

This is a secondary analysis of a multicenter observational obstetric cohort. Trained research personnel abstracted maternal and neonatal records of greater than 115,000 pregnant women from 25 hospitals (2008-2011). Women at term with singleton, nonanomalous, vertex, liveborn neonates were included in two cohorts: 1) nulliparous women (n=35,529); and 2) multiparous women with prior vaginal deliveries only (n=39,871). Women were grouped as non-Hispanic black, non-Hispanic white, Hispanic, and Asian. Multivariable logistic regression was used to evaluate the following outcomes: overall cesarean delivery frequency, indications for cesarean delivery, and utilization of labor management strategies intended to safely reduce cesarean delivery.

RESULTS

A total of 75,400 women were eligible for inclusion, of whom 47% (n=35,529) were in the nulliparous cohort and 53% (n=39,871) were in the multiparous cohort. The frequencies of cesarean delivery were 25.8% among nulliparous women and 6.0% among multiparous women. For nulliparous women, the unadjusted cesarean delivery frequencies were 25.0%, 28.3%, 28.7%, and 24.0% for non-Hispanic white, non-Hispanic black, Asian, and Hispanic women, respectively. Among nulliparous women, the adjusted odds of cesarean delivery were higher in all racial and ethnic groups compared with non-Hispanic white women (non-Hispanic black adjusted odds ratio [OR] 1.47, 95% CI 1.36-1.59; Asian adjusted OR 1.26, 95% CI 1.14-1.40; Hispanic adjusted OR 1.17, 95% CI 1.07-1.27) as a result of greater odds of cesarean delivery both for nonreassuring fetal status and labor dystocia. Nonapplication of labor management strategies regarding failed induction, arrest of dilation, arrest of descent, or cervical ripening did not contribute to increased odds of cesarean delivery for non-Hispanic black and Hispanic women. Compared with non-Hispanic white women, Hispanic women were actually less likely to experience elective cesarean delivery (adjusted OR 0.60, 95% CI 0.42-0.87) or cesarean delivery for arrest of dilation before 4 hours (adjusted OR 0.67, 95% CI 0.49-0.92). Additionally, compared with non-Hispanic white women, Asian women were more likely to experience cesarean delivery for nonreassuring fetal status (adjusted OR 1.29, 95% CI 1.09-1.53) and to have had that cesarean delivery be performed in the setting of a 1-minute Apgar score 7 or greater (adjusted OR 1.79, 95% CI 1.07-3.00). A similar trend was seen among multiparous women with prior vaginal deliveries.

CONCLUSION

Although racial and ethnic disparities exist in the frequency of cesarean delivery, differential use of labor management strategies intended to reduce the cesarean delivery rate does not appear to be associated with these racial and ethnic disparities.

A pilot randomised controlled trial exploring the effects of antenatal reflexology on labour outcomes

OBJECTIVE

to investigate the effects of antenatal reflexology on labour outcomes.

DESIGN

secondary analysis of a pilot three-armed randomised controlled trial conducted between July 2012 and September 2013.

SETTING

a large UK inner city hospital maternity department.

PARTICIPANTS

ninety primiparous women with a singleton pregnancy experiencing low back and / or pelvic girdle pain.

INTERVENTIONS

six weekly 30-minute reflexology treatments compared to sham (footbath) treatments or usual antenatal care only.

MEASUREMENTS

labour outcome data including labour onset, duration of the second stage of labour, epidural and Entonox usage, and mode of delivery. Participant feedback was collected prior to each treatment.

FINDINGS

labour outcomes were collected for 61 women (95.3%) who completed the study. The second stage of labour duration data, available for 42 women (62.5%) who had vaginal births, showed a mean reduction of 44minutes in the reflexology group (73.56minutes; SD= 53.78) compared to the usual care (117.92minutes; SD=56.15) (p<0.05) and footbath groups (117.4minutes; SD=68.54) (p=0.08). No adverse effects were reported.

KEY CONCLUSIONS

in this trial antenatal reflexology reduced labour duration for primiparous women who had experienced low back and/ or pelvic girdle pain during their pregnancy, compared with usual care and footbaths.

IMPLICATIONS FOR PRACTICE

reflexology is suitable for use during pregnancy, is safe and enjoyable and may reduce labour duration. Midwives may wish to recommend reflexology to promote normal childbirth and facilitate women centred care.

TRIAL REGISTRATION

this trial was listed with the International Standard Randomised Controlled Trial Number Register (ISRCTN26607527).

Pushing/bearing down methods for the second stage of labour

BACKGROUND

Maternal pushing during the second stage of labour is an important and indispensable contributor to the involuntary expulsive force developed by uterine contraction. There is no consensus on an ideal strategy to facilitate these expulsive efforts and there are contradictory results about the influence on the mother and fetus.

OBJECTIVES

To evaluate the benefits and possible disadvantages of different kinds of techniques regarding maternal pushing/breathing during the expulsive stage of labour on maternal and fetal outcomes.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (19 September 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs assessing the effects of pushing/bearing down techniques (type and/or timing) performed during the second stage of labour on maternal and neonatal outcomes. Cluster-RCTs were eligible for inclusion, but none were identified. Studies using a cross-over design and those published in abstract form only were not eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data and assessed risk of bias. Data were checked for accuracy.

MAIN RESULTS

In this updated review, we included 21 studies in total, eight (884 women) comparing spontaneous pushing versus directed pushing, with or without epidural analgesia and 13 (2879 women) comparing delayed pushing versus immediate pushing with epidural analgesia. Our GRADE assessments of evidence ranged from moderate to very low quality; the main reasons for downgrading were study design limitations and imprecision of effect estimates. Overall, the included studies varied in their risk of bias; most were judged to be at unclear risk of bias. Comparison 1: types of pushing: spontaneous pushing versus directed pushingThere was no clear difference in the duration of the second stage of labour (mean difference (MD) 10.26 minutes; 95% confidence interval (CI) -1.12 to 21.64 minutes, six studies, 667 women, random-effects, I² = 81%) (very low-quality evidence). There was no clear difference in 3rd or 4th degree perineal laceration (risk ratio (RR) 0.87; 95% CI 0.45 to 1.66, one study, 320 women) (low-quality evidence), episiotomy (average RR 1.05; 95% CI 0.60 to 1.85, two studies, 420 women, random-effects, I² = 81%), duration of pushing (MD -9.76 minutes, 95% CI -19.54 to 0.02; two studies; 169 women; I² = 88%) (very low-quality evidence), or rate of spontaneous vaginal delivery (RR 1.01, 95% CI 0.97 to 1.05; five studies; 688 women; I² = 2%) (moderate-quality evidence). For primary neonatal outcomes such as five-minute Apgar score less than seven, there was no clear difference between groups (RR 0.35; 95% CI 0.01 to 8.43, one study, 320 infants) (very low-quality evidence), and the number of admissions to neonatal intensive care (RR 1.08; 95% CI 0.30 to 3.79, two studies, 393 infants) (very low-quality evidence) also showed no clear difference between spontaneous and directed pushing. No data were available on hypoxic ischaemic encephalopathy. Comparison 2: timing of pushing: delayed pushing versus immediate pushing (all women with epidural)For the primary maternal outcomes, delayed pushing was associated with an increase of 56 minutes in the duration of the second stage of labour (MD 56.40, 95% CI 42.05 to 70.76; 11 studies; 3049 women; I² = 91%) (very low-quality evidence), but no clear difference in third or 4th degree perineal laceration (RR 0.94; 95% CI 0.78 to 1.14, seven studies. 2775 women) (moderate-quality evidence) or episiotomy (RR 0.95; 95% CI 0.87 to 1.04, five studies, 2320 women). Delayed pushing was also associated with a 19-minute decrease in the duration of pushing (MD -19.05, 95% CI -32.27 to -5.83; 11 studies; 2932 women; I² = 95%) (very low-quality evidence) and an increase in spontaneous vaginal delivery (RR 1.07; 95% CI 1.02 to 1.11, 12 studies, 3114 women) (moderate-quality evidence).For the primary neonatal outcomes, there was no clear difference between groups in admission to neonatal intensive care (RR 0.98; 95% CI 0.67 to 1.41, three studies, n = 2197) (low-quality evidence) and five-minute Apgar score less than seven (RR 0.15; 95% CI 0.01 to 3.00; three studies; 413 infants) (very low-quality evidence). There were no data on hypoxic ischaemic encephalopathy. Delayed pushing was associated with a greater incidence of low umbilical cord blood pH (RR 2.24; 95% CI 1.37 to 3.68, 4 studies, 2145 infants) and increased the cost of intrapartum care by CDN$ 68.22 (MD 68.22, 95% CI 55.37, 81.07, one study, 1862 women).

AUTHORS' CONCLUSIONS

This updated review is based on 21 included studies of moderate to very low quality of evidence (with evidence mainly downgraded due to study design limitations and imprecision of effect estimates).Timing of pushing with epidural is consistent in that delayed pushing leads to a shortening of the actual time pushing and increase of spontaneous vaginal delivery at the expense of an overall longer duration of the second stage of labour and an increased risk of a low umbilical cord pH (based only on one study). Nevertheless, there was no clear difference in serious perineal laceration and episiotomy, and in other neonatal outcomes (admission to neonatal intensive care, five-minute Apgar score less than seven and delivery room resuscitation) between delayed and immediate pushing.Therefore, for the type of pushing, with or without epidural, there is no conclusive evidence to support or refute any specific style as part of routine clinical practice, and in the absence of strong evidence supporting a specific method or timing of pushing, the woman's preference and comfort and clinical context should guide decisions.Further properly well-designed RCTs, addressing clinically important maternal and neonatal outcomes are required to add evidence-based information to the current knowledge. Such trials will provide more complete data to be incorporated into a future update of this review.

Durations of second stage of labor and pushing, and adverse neonatal outcomes: a population-based cohort study

OBJECTIVE

The associations between duration of second stage of labor, pushing time and risk of adverse neonatal outcomes are not fully established. Therefore, we aimed to examine such relationships.

STUDY DESIGN

A population-based cohort study including 42 539 nulliparous women with singleton infants born in cephalic presentation at ⩾37 gestational weeks, using the Stockholm-Gotland Obstetric Cohort, Sweden, and the Swedish Neonatal Quality Register, 2008 to 2013. Poisson regression was used to analyze estimated adjusted relative risks (RRs), with 95% confidence intervals (CIs). Outcome measures were umbilical artery acidosis (pH <7.05 and base excess <-12), birth asphyxia-related complications (including any of the following conditions: hypoxic ischemic encephalopathy, hypothermia treatment, neonatal seizures, meconium aspiration syndrome or advanced resuscitation after birth) and admission to neonatal intensive care unit (NICU).

RESULTS

Overall rates of umbilical artery acidosis, birth asphyxia-related complications and admission to NICU were 1.08, 0.63 and 6.42%, respectively. Rate of birth asphyxia-related complications gradually increased with duration of second stage: from 0.42% at <1 h to 1.29% at ≥4 h (adjusted RR 2.46 (95% CI 1.66 to 3.66)). For admission to NICU, corresponding rates were 4.97 and 9.45%, and adjusted RR (95% CI) was 1.80 (95% CI 1.58 to 2.04). Compared with duration of pushing <15 min, a duration of pushing ⩾60 min increased rates of acidosis from 0.57 to 1.69% (adjusted RR 2.55 (95% CI 1.51 to 4.30)).

CONCLUSION

Prolonged durations of second stage of labor and pushing are associated with increased RRs of adverse neonatal outcomes. Clinical assessment of fetal well-being is essential when durations of second stage and pushing increases.