Neonatal and Maternal Adverse Outcomes Among Low-Risk Parous Women at 39-41 Weeks of Gestation

[Fetal death: Expert consensus from the College of French Gynecologists and Obstetricians]

Fetal death is defined as the spontaneous cessation of cardiac activity after fourteen weeks of amenorrhea. In France, the prevalence of fetal death after 22 weeks is between 3.2 and 4.4/1000 births. Regarding the prevention of fetal death in the general population, it is not recommended to counsel for rest and not to prescribe vitamin A, vitamin D nor micronutrient supplementation for the sole purpose of reducing the risk of fetal death (Weak recommendations; Low quality of evidence). It is not recommended to prescribe aspirin (Weak recommendation; Very low quality of evidence). It is recommended to offer vaccination against influenza in epidemic periods and against SARS-CoV-2 (Strong recommendations; Low quality of evidence). It is not recommended to systematically look for nuchal cord encirclements during prenatal screening ultrasounds (Strong Recommendation; Low Quality of Evidence) and not to perform systematic antepartum monitoring by cardiotocography (Weak Recommendation; Very Low Quality of Evidence). It is not recommended to ask women to perform an active fetal movement count to reduce the risk of fetal death (Strong Recommendation; High Quality of Evidence). Regarding evaluation in the event of fetal death, it is suggested that an external fetal examination be systematically offered (Expert opinion). It is recommended that a fetopathological and anatomopathological examination of the placenta be carried out to participate in cause identification (Strong Recommendation. Moderate quality of evidence). It is recommended that chromosomal analysis by microarray testing be performed rather than conventional karyotype, in order to be able to identify a potentially causal anomaly more frequently (Strong Recommendation, moderate quality of evidence); to this end, it is suggested that postnatal sampling of the placental fetal surface for genetic purposes be preferred (Expert Opinion). It is suggested to test for antiphospholipid antibodies and systematically perform a Kleihauer test and a test for irregular agglutinins (Expert opinion). It is suggested to offer a summary consultation, with the aim of assessing the physical and psychological status of the parents, reporting the results, discussing the cause and providing information on monitoring for a subsequent pregnancy (Expert opinion). Regarding announcement and support, it is suggested to announce fetal death without ambiguity, using simple words and adapting to each situation, and then to support couples with empathy in the various stages of their care (Expert opinion). Regarding management, it is suggested that, in the absence of a situation at risk of disseminated intravascular coagulation or maternal vitality, the patient's wishes should be taken into account when determining the time between the diagnosis of fetal death and induction of birth. Returning home is possible if it's the patient wish (Expert opinion). In all situations excluding maternal life-threatening emergencies, the preferred mode of delivery is vaginal delivery, regardless the history of cesarean section(s) history (Expert opinion). In the event of fetal death, it is recommended that mifepristone 200mg be prescribed at least 24hours before induction, to reduce the delay between induction and delivery (Low recommendation. Low quality of evidence). There are insufficient data in the literature to make a recommendation regarding the route of administration (vaginal or oral) of misoprostol, neither the type of prostaglandin to reduce induction-delivery time or maternal morbidity. It is suggested that perimedullary analgesia be introduced at the start of induction if the patient asks, regardless of gestational age. It is suggested to prescribe cabergoline immediately in the postpartum period in order to avoid lactation, whatever the gestational age, after discussing the side effects of the treatment with the patient (Expert opinion). The risk of recurrence of fetal death after unexplained fetal death does not appear to be increased in subsequent pregnancies, and data from the literature are insufficient to make a recommendation on the prescription of aspirin. In the event of a history of fetal death due to vascular issues, low-dose aspirin is recommended to reduce perinatal morbidity, and should not be combined with heparin therapy (Low recommendation, very low quality of evidence). It is suggested not to recommend an optimal delay before initiating another pregnancy just because of the history of fetal death. It is suggested that the woman and co-parent be informed of the possibility of psychological support. Fetal heart rate monitoring is not indicated solely because of a history of fetal death. It is suggested that delivery not be systematically induced. However, induction can be considered depending on the context and parental request. The gestational age will be discussed, taking into account the benefits and risks, especially before 39 weeks. If a cause of fetal death is identified, management will be adapted on a case-by-case basis (expert opinion). In the event of fetal death occurring in a twin pregnancy, it is suggested that the surviving twin be evaluated as soon as the diagnosis of fetal death is made. In the case of dichorionic pregnancy, it is suggested to offer ultrasound monitoring on a monthly basis. It is suggested not to deliver prematurely following fetal death of a twin. If fetal death occurs in a monochorionic twin pregnancy, it is suggested to contact the referral competence center, in order to urgently look for signs of acute fetal anemia on ultrasound in the surviving twin, and to carry out weekly ultrasound monitoring for the first month. It is suggested not to induce birth immediately.

The efficacy and safety of 25 μg or 50 μg oral misoprostol versus 25 μg vaginal misoprostol given at 4- or 6-hourly intervals for induction of labour in women at or beyond term with live singleton pregnancies: A systematic review and meta-analysis

BACKGROUND

Misoprostol is widely used for cervical ripening and labour induction as it is heat-stable and inexpensive. Oral misoprostol 25 μg given 2-hourly is recommended over vaginal misoprostol 25 μg given 6-hourly, but the need for 2-hourly fetal monitoring makes oral misoprostol impractical for routine use in high-volume obstetric units in resource-constrained settings.

OBJECTIVES

To compare the efficacy and safety of oral misoprostol initiated at 25 or 50 μg versus 25 μg vaginal misoprostol given at 4- to 6-hourly intervals for labor induction in women at or beyond term (≥ 37 weeks) with a single viable fetus and an unscarred uterus.

SEARCH STRATEGY

We identified eligible randomized, parallel-group, labor-induction trials from recent systematic reviews. We additionally searched PubMed, Cochrane CENTRAL, Epistemonikos, and clinical trials registries from February 1, 2020 to December 31, 2022 without language restrictions. Database-specific keywords for cervical priming, labor induction, and misoprostol were used.

SELECTION CRITERIA

We excluded labor-induction trials exclusively in women with ruptured membranes, in the third trimester, and those that initiated misoprostol at doses not specified in the review's objectives. The primary outcomes were vaginal birth within 24 h, cesarean section, perinatal mortality, neonatal morbidity, and maternal morbidity. The secondary outcomes were uterine hyperstimulation with fetal heart rate changes, and oxytocin augmentation.

DATA COLLECTION AND ANALYSIS

Two or more authors selected studies independently, assessed risk of bias, and extracted data. We derived pooled weighted risk ratios with 95% confidence intervals (CIs) for each outcome, subgrouping trials by the dose and frequency of misoprostol regimens. We used the I2 statistic to quantify heterogeneity and the random-effects model for meta-analysis when appropriate. We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach to assess certainty (confidence) in the effect estimates.

MAIN RESULTS

Thirteen trials, from Canada, India, Iran, and the US, randomizing 2941 women at ≥37 weeks of gestation with an unfavorable cervix (Bishop score <6), met the eligibility criteria. Five misoprostol regimens were compared: 25 μg oral versus 25 μg vaginal, 4-hourly (three trials); 50 μg oral versus 25 μg vaginal, 4-hourly (five trials); 50 μg followed by 100 μg oral versus 25 μg vaginal, 4-hourly (two trials); 50 μg oral, 4-hourly versus 25 μg vaginal, 6-hourly (one trial); and 50 μg oral versus 25 μg vaginal, 6-hourly (two trials). The overall certainty in the evidence ranged from moderate to very low, due to high risk of bias in 11/13 trials (affecting all outcomes), unexplained heterogeneity (1/7 outcomes), indirectness (1/7 outcomes), and imprecision (4/7 outcomes). Vaginal misoprostol probably increased vaginal deliveries within 24 h compared with oral misoprostol (risk ratio [RR] 0.82, 95% CI 0.70-0.96; 11 trials, 2721 mothers; moderate-certainty evidence); this was more likely with 4-hourly than with 6-hourly vaginal regimens. The risk of cesarean sections did not appreciably differ (RR 1.00, 95% CI 0.80-1.26; 13 trials, 2941 mothers; very low-certainty evidence), although oral misoprostol 25 μg 4-hourly probably increased this risk compared with 25 μg vaginal misoprostol 4-hourly (RR 1.69, 95% CI 1.21-2.36; three trials, 515 mothers). The risk of perinatal mortality (RR 0.67, 95% CI 0.11-3.90; one trial, 196 participants; very low-certainty evidence), neonatal morbidity (RR 0.84, 95% CI 0.67-1.06; 13 trials, 2941 mothers; low-certainty evidence), and maternal morbidity (RR 0.83, 95% CI 0.48-1.44; 6 trials; 1945 mothers; moderate-certainty evidence) did not differ appreciably. The risk of uterine hyperstimulation with fetal heart rate changes may be lower with oral misoprostol (RR 0.70, 95% CI 0.52-0.95; 10 trials, 2565 mothers; low-certainty evidence). Oxytocin augmentation was probably more frequent with oral compared with vaginal misoprostol (RR 1.29, 95% CI 1.10-1.51; 13 trials, 2941 mothers; moderate-certainty evidence).

CONCLUSIONS

Low-dose, 4- to 6-hourly vaginal misoprostol regimens probably result in more vaginal births within 24 h and less frequent oxytocin use compared with low-dose, 4- to 6-hourly, oral misoprostol regimens. Vaginal misoprostol may increase the risk of uterine hyperstimulation with fetal heart changes compared with oral misoprostol, without increasing the risk of perinatal mortality, neonatal morbidity, or maternal morbidity. Indirect evidence indicates that 25 μg vaginal misoprostol 4-hourly may be more effective and as safe as the recommended 6-hourly vaginal regimen. This evidence could inform clinical decisions in high-volume obstetric units in resource-constrained settings.

Perinatal and maternal outcomes according to timing of induction of labour: A systematic review and meta-analysis

The risk of adverse perinatal and maternal outcomes increases with gestational age, and although induction of labour may reduce these risks, the optimal timing of induction remains unknown. We carried out a systematic review and meta-analysis, to determine the gestational age at which induction should be offered. We searched Cochrane Central Register of Controlled Trials, Medline, and Embase databases from inception to July 2022, to identify randomised trials comparing induction of labour at or beyond 37' weeks gestation with expectant management or delayed induction, and according to the gestational age at planned induction. We undertook random effects meta-analysis and pooled estimates as odds ratios with 95% confidence intervals. We assessed risk of bias of studies using the Cochrane Risk of Bias tool 2.0. We included 44 trials (23,960 women and 22,191 offspring) from 1,839 citations in our meta-analysis. The odds of perinatal death (odds ratio 0.42, 95% confidence interval 0.22 to 0.81; 26 studies, 20,154 offspring), stillbirth (0.40, 0.16 to 0.98; 25 studies, 19,412 offspring), admission to neonatal intensive care unit (0.86, 0.78 to 0.96; 23 studies, 18,846 offspring), and caesarean section (0.90, 0.83 to 0.98; 40 studies, 23,616 women) were reduced in the induction of labour group compared to expectant management or delayed induction. The odds of admission to neonatal intensive care unit (0.82, 0.70 to 0.96; 6 studies, 9,316 offspring) were lower with induction of labour at 41 weeks compared to induction at or after 42 weeks' gestation, and the odds of caesarean section were reduced with labour induction at 39 weeks' compared to induction at or after 40 weeks' (0.83, 0.74 to 0.93; 8 studies, 7,677 women). There were no significant differences in pregnancy outcomes by method of induction of labour. Induction of labour compared to expectant management or delayed induction reduces the risk of adverse pregnancy outcomes, and the optimal timing may depend on the specific outcome of interest.

Hypertension in pregnancy and adverse outcomes among low-risk nulliparous women expectantly managed at or after 39 weeks: a secondary analysis of a randomised controlled trial

OBJECTIVE

To evaluate whether hypertensive disorders of pregnancy (HDP) among low-risk nulliparous women expectantly managed at or after 39 weeks of gestation are associated with adverse outcomes.

DESIGN

Secondary analysis of a randomised trial.

SETTING

Multicentre, USA.

POPULATION

Individuals in the expectantly managed group who delivered on or after 39 weeks.

METHODS

Multivariable analysis to estimate adjusted relative risks (aRR) for binomial outcomes, adjusted odds ratios (aOR) for multinomial outcomes and 95% CI.

MAIN OUTCOME MEASURES

Composite adverse maternal outcome including placental abruption, pulmonary oedema, postpartum haemorrhage, postpartum infection, venous thromboembolism or intensive care unit admission. Secondary outcomes included a composite of perinatal death or severe neonatal complications, mode of delivery, small and large for gestational age and neonatal intermediate or intensive unit length of stay.

RESULTS

Of the 3044 women randomised to expectant management in the original trial, 2718 (89.3%) were eligible for this analysis, of whom 373 (13.7%) developed HDP. Compared with participants who remained normotensive, those who developed HDP were more likely to experience the maternal composite (12% versus 6%, aRR 1.84, 95% CI 1.33-2.54) and caesarean delivery (29% versus 23%, aOR 1.32, 95% CI 1.01-1.71). Differences between the two groups were not significantly different for the adverse perinatal composite (7% versus 5%, aRR 1.38, 95% CI 0.92-2.07) or for other secondary outcomes.

CONCLUSION

Almost 14% of low-risk nulliparous individuals expectantly managed at 39 weeks developed HDP, and were more likely to experience adverse maternal outcomes compared with those who did not develop HDP.

TWEETABLE ABSTRACT

Almost 14% of low-risk nulliparous individuals expectantly managed at 39 weeks developed hypertensive disorders of pregnancy, and were more likely to experience adverse maternal outcomes compared with those who did not develop hypertensive disorders.

Adverse Outcomes among Low-Risk Pregnancies at 39 to 41 Weeks: Stratified by Birth Weight Percentile

OBJECTIVE

This study aimed to assess the risk of adverse outcomes among low-risk pregnancies at 39 to 41 weeks, stratified by birth weight percentile.

STUDY DESIGN

This retrospective cohort study utilized the U.S. vital statistics datasets (2013-2017) and evaluated low-risk women with nonanomalous cephalic singleton gestations who labored and delivered at 39 to 41 weeks, regardless of ultimate mode of delivery. Newborns were categorized as small (<10th percentile), large (>90th percentile), or appropriate (10-90th percentile) for gestational ages (SGA, LGA, and AGA, respectively). The primary outcome, composite neonatal adverse outcome (CNAO), included Apgar's score <5 at 5 minutes, assisted ventilation >6 hours, seizure, or neonatal death. The secondary outcome, composite maternal adverse outcome (CMAO), included intensive care unit admission, blood transfusion, uterine rupture, or unplanned hysterectomy. Multivariable Poisson's regression was used to estimate the association (using adjusted relative risk [aRR] and 95% confidence interval [CI]).

RESULTS

Of 19.8 million live births during the study interval, approximately 8.9 million (44.9%) met the inclusion criteria, with 9.9% being SGA, 9.2% being LGA, and 80.9% being AGA. SGA newborns delivered at 40 (aRR = 1.17; 95% CI: 1.12-1.23) and at 41 weeks (aRR = 1.55; 95% CI: 1.45-1.66) had a higher risk of CNAO than at 39 weeks. Similarly, LGA newborns delivered at 40 (aRR = 1.13; 95% CI: 1.07-1.19) and 41 weeks (aRR = 1.44; 95% CI: 1.35-1.54) and AGA newborns delivered at 40 (aRR = 1.24; 95% CI: 1.21-1.26) and 41 weeks (aRR = 1.57; 95% CI: 1.53-1.61) also had a higher risk of CNAO than at 39 weeks. CMAO was also significantly higher at 40 and 41 weeks than at 39 weeks, regardless of whether the mothers delivered SGA, LGA, or AGA newborns.

CONCLUSION

Among low-risk pregnancies, the risks of composite neonatal and maternal adverse outcomes increase from 39 through 41 weeks' gestation, irrespective of whether newborns are SGA, LGA, or AGA.

Apgar score at 10 minutes and adverse outcomes among low-risk pregnancies

OBJECTIVE

Among low-risk pregnancies, we ascertained the association between 10-minute Apgar score and adverse outcomes of newborn infants.

METHOD

We conducted a retrospective cohort study using the U.S. vital statistics datasets (2011-2018), which included live births from low-risk women with non-anomalous singleton gestations who delivered at 37-41 weeks. When a newborn infant had an abnormal 5-minute Apgar score (0-5), a 10-minute Apgar score was documented in the birth certificate. Apgar score at 10 min was categorized as low (0-3), moderate (4-6), and normal (7-10). The primary outcome was composite neonatal adverse outcome. The secondary outcomes were individual neonatal adverse outcomes and infant mortality. Multivariable Poisson regression analyses were used to estimate the association between 10-minute Apgar score and adverse outcomes (using adjusted relative risk [aRR] and 95% confidence intervals [CI]).

RESULTS

Of 31.5 million live births delivered (2011-2018), 111,163 (0.4%) met inclusion criteria; of them, 74.2%, 20.7%, and 5.1% had normal, moderate, and low 10-minute Apgar scores, respectively. The overall composite neonatal adverse outcome was 100.6 per 1,000 live births and the risk was significantly higher among those with a moderate (aRR 3.19; 95% CI 3.06-3.31) or low 10-minute Apgar score (aRR 6.62; 95% CI 6.34-6.91) than with a normal 10-minute Apgar score. Infant mortality also showed a similar pattern. Newborn infants with improved Apgar scores from 5 to 10 min were associated with lower risks of the composite neonatal adverse outcome, as well as infant mortality, than those with scores that remained stable.

CONCLUSION

Among low-risk pregnancies, newborn infants with a lower 10-minute Apgar score were associated with a higher risk of adverse outcomes.

Association between Maternal Obesity Class, Adherence to Labor Guidelines, and Perinatal Outcomes

Background  Data are limited concerning rates of perinatal complications in women with a body mass index (BMI) ≥40 kg/m2 compared to women with other BMI classes when guidelines for the safe prevention of the primary cesarean delivery are applied. Objective  The aim of the study is to evaluate labor guideline adherence by BMI class and to compare perinatal outcomes across BMI classes with guideline adherent management. Study Design  This retrospective study included low-risk women admitted for delivery between April 2014 and April 2017 after the labor guidelines were implemented. BMI closest to delivery was used for analysis. Women with cesarean for nonreassuring fetal status were excluded. Results  Guideline adherence decreased with increasing BMI, with 93% adherence among women of normal weight compared to 81% for class III obese women ( p  < 0.0001). Among women who had guideline-adherent management, there was increased rates of cesarean among class III versus other obesity classes; however, there were no differences in rates of infectious morbidity ( p  = 0.98) or hemorrhage ( p  = 0.93). Although newborns of women with class III obesity had higher rates of meconium at birth, neonatal outcomes were not different with increasing maternal BMI ( p  = 0.65). Conclusion  There were no differences in adverse perinatal outcomes with increasing BMI.

Neonatal and Maternal Composite Adverse Outcomes Among Low-Risk Nulliparous Women Compared With Multiparous Women at 39-41 Weeks of Gestation

OBJECTIVE

To estimate whether the frequency of adverse maternal and neonatal outcomes differs between low-risk nulliparous and multiparous women at 39-41 weeks of gestation.

METHODS

This is a secondary analysis of an observational obstetrics cohort of maternal-neonatal dyads at 25 hospitals. Low-risk women with nonanomalous singletons who delivered between 39 0/7 and 41 6/7 weeks of gestation were included. The composite neonatal adverse outcome included 5-minute Apgar score less than five, ventilator support or cardiopulmonary resuscitation, seizure, hypoxic ischemic encephalopathy, sepsis, bronchopulmonary dysplasia, persistent pulmonary hypertension, necrotizing enterocolitis, birth injury or perinatal death. The composite maternal adverse outcome included infection, third- or fourth-degree perineal laceration, thromboembolism, transfusion of blood products, or maternal death. Small for gestational age (SGA), large for gestational age (LGA), and shoulder dystocia requiring maneuvers were also evaluated. Multivariable regression was used to estimate adjusted relative risks (aRRs) and adjusted odds ratios (aORs) with 95% CIs.

RESULTS

Of the 115,502 women in the overall cohort, 39,870 (34.5%) met eligibility criteria for this analysis; 18,245 (45.8%) were nulliparous. The risk of the composite neonatal adverse outcome (1.5% vs 1.0%, aRR 1.80, 95% CI 1.48-2.19), composite maternal adverse outcome (15.1% vs 3.3%, aRR 5.04, 95% CI 4.62-5.49), and SGA (8.9% vs 5.8%, aOR 1.45, 95% CI 1.33-1.57) was significantly higher in nulliparous than multiparous patients. The risk of LGA (aOR 0.65, 95% CI 0.60-0.71) and shoulder dystocia with maneuvers (aRR 0.68, 95% CI 0.60-0.77) was significantly lower in nulliparous rather than multiparous patients.

CONCLUSION

The risk of composite adverse outcomes and SGA among low-risk nulliparous women at 39-41 weeks of gestation is significantly higher than among multiparous counterparts. However, nulliparous women had a lower risk of shoulder dystocia with maneuvers and LGA.

Induction of labour at or beyond 37 weeks' gestation

BACKGROUND

Risks of stillbirth or neonatal death increase as gestation continues beyond term (around 40 weeks' gestation). It is unclear whether a policy of labour induction can reduce these risks. This Cochrane Review is an update of a review that was originally published in 2006 and subsequently updated in 2012 and 2018.

OBJECTIVES

To assess the effects of a policy of labour induction at or beyond 37 weeks' gestation compared with a policy of awaiting spontaneous labour indefinitely (or until a later gestational age, or until a maternal or fetal indication for induction of labour arises) on pregnancy outcomes for the infant and the mother.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (17 July 2019), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) conducted in pregnant women at or beyond 37 weeks, comparing a policy of labour induction with a policy of awaiting spontaneous onset of labour (expectant management). We also included trials published in abstract form only. Cluster-RCTs, quasi-RCTs and trials using a cross-over design were not eligible for inclusion in this review. We included pregnant women at or beyond 37 weeks' gestation. Since risk factors at this stage of pregnancy would normally require intervention, only trials including women at low risk for complications, as defined by trialists, were eligible. The trials of induction of labour in women with prelabour rupture of membranes at or beyond term were not considered in this review but are considered in a separate Cochrane Review.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, assessed risk of bias and extracted data. Data were checked for accuracy. We assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

In this updated review, we included 34 RCTs (reporting on over 21,000 women and infants) mostly conducted in high-income settings. The trials compared a policy to induce labour usually after 41 completed weeks of gestation (> 287 days) with waiting for labour to start and/or waiting for a period before inducing labour. The trials were generally at low to moderate risk of bias. Compared with a policy of expectant management, a policy of labour induction was associated with fewer (all-cause) perinatal deaths (risk ratio (RR) 0.31, 95% confidence interval (CI) 0.15 to 0.64; 22 trials, 18,795 infants; high-certainty evidence). There were four perinatal deaths in the labour induction policy group compared with 25 perinatal deaths in the expectant management group. The number needed to treat for an additional beneficial outcome (NNTB) with induction of labour, in order to prevent one perinatal death, was 544 (95% CI 441 to 1042). There were also fewer stillbirths in the induction group (RR 0.30, 95% CI 0.12 to 0.75; 22 trials, 18,795 infants; high-certainty evidence); two in the induction policy group and 16 in the expectant management group. For women in the policy of induction arms of trials, there were probably fewer caesarean sections compared with expectant management (RR 0.90, 95% CI 0.85 to 0.95; 31 trials, 21,030 women; moderate-certainty evidence); and probably little or no difference in operative vaginal births with induction (RR 1.03, 95% CI 0.96 to 1.10; 22 trials, 18,584 women; moderate-certainty evidence). Induction may make little or difference to perineal trauma (severe perineal tear: RR 1.04, 95% CI 0.85 to 1.26; 5 trials; 11,589 women; low-certainty evidence). Induction probably makes little or no difference to postpartum haemorrhage (RR 1.02, 95% CI 0.91 to 1.15, 9 trials; 12,609 women; moderate-certainty evidence), or breastfeeding at discharge (RR 1.00, 95% CI 0.96 to 1.04; 2 trials, 7487 women; moderate-certainty evidence). Very low certainty evidence means that we are uncertain about the effect of induction or expectant management on the length of maternal hospital stay (average mean difference (MD) -0.19 days, 95% CI -0.56 to 0.18; 7 trials; 4120 women; Tau² = 0.20; I² = 94%). Rates of neonatal intensive care unit (NICU) admission were lower (RR 0.88, 95% CI 0.80 to 0.96; 17 trials, 17,826 infants; high-certainty evidence), and probably fewer babies had Apgar scores less than seven at five minutes in the induction groups compared with expectant management (RR 0.73, 95% CI 0.56 to 0.96; 20 trials, 18,345 infants; moderate-certainty evidence). Induction or expectant management may make little or no difference for neonatal encephalopathy (RR 0.69, 95% CI 0.37 to 1.31; 2 trials, 8851 infants; low-certainty evidence, and probably makes little or no difference for neonatal trauma (RR 0.97, 95% CI 0.63 to 1.49; 5 trials, 13,106 infants; moderate-certainty evidence) for induction compared with expectant management. Neurodevelopment at childhood follow-up and postnatal depression were not reported by any trials. In subgroup analyses, no differences were seen for timing of induction (< 40 versus 40-41 versus > 41 weeks' gestation), by parity (primiparous versus multiparous) or state of cervix for any of the main outcomes (perinatal death, stillbirth, NICU admission, caesarean section, operative vaginal birth, or perineal trauma).

AUTHORS' CONCLUSIONS

There is a clear reduction in perinatal death with a policy of labour induction at or beyond 37 weeks compared with expectant management, though absolute rates are small (0.4 versus 3 deaths per 1000). There were also lower caesarean rates without increasing rates of operative vaginal births and there were fewer NICU admissions with a policy of induction. Most of the important outcomes assessed using GRADE had high- or moderate-certainty ratings. While existing trials have not yet reported on childhood neurodevelopment, this is an important area for future research. The optimal timing of offering induction of labour to women at or beyond 37 weeks' gestation needs further investigation, as does further exploration of risk profiles of women and their values and preferences. Offering women tailored counselling may help them make an informed choice between induction of labour for pregnancies, particularly those continuing beyond 41 weeks - or waiting for labour to start and/or waiting before inducing labour.