No. 214-Guidelines for the Management of Pregnancy at 41+0 to 42+0 Weeks

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.

Research Update: Healthy Birth Practice #1-Let Labor Begin on Its Own

This article is an adaptation for print of Debby Amis's presentation at the 2022 Lamaze Virtual Conference. She discusses worldwide recommendations as to the optimal time for routine labor induction for low-risk pregnant persons, the recent research about the optimal time for routine labor induction, and recommendations to help the pregnant family make an informed decision about routine induction. This article includes an important new study not included in the Lamaze Virtual Conference that found an increase in perinatal deaths for low-risk pregnancies that were induced at 39 weeks as compared to low-risk pregnancies not induced at 39 weeks but were delivered no later than 42 weeks.

Fetal Movement Counting in Prolonged Pregnancies: The COMPTAMAF Prospective Randomized Trial

In prolonged pregnancies, the risks of neonatal morbidity and mortality are increased. The aim of this trial was to assess the benefits of maternal information about fetal movement (FM) counting on neonatal outcomes in prolonged pregnancy. It was a prospective, single center, randomized, open-label study conducted from October 2019 to March 2022. Intention-to-treat analyses were performed on 278 patients randomized into two 1:1 groups (control group and FM counting group). The primary outcome was a composite score of neonatal morbidity (presence of two of the following items: fetal heart rate abnormality at delivery, Apgar score of <7 at 5 min, umbilical cord arterial pH of <7.20, and acute respiratory distress with mutation in neonatal intensive care unit). There was no significant difference between the two groups in the rate of neonatal morbidity (14.0% in the FM counting group versus 22.9% in the standard information group; p = 0.063; OR 0.55, 95% CI 0.29−1.0). In this study, fetal movement counting for women in prolonged pregnancy failed to demonstrate a significant reduction in adverse neonatal outcomes.

Outcomes of induction versus spontaneous onset of labour at 40 and 41 GW: findings from a prospective database, Sri Lanka

Objectives

The World Health Organization recommends induction of labour (IOL) for low risk pregnancy from 41 + 0 gestational weeks (GW). Nevertheless, in Sri Lanka IOL at 40 GW is a common practice. This study compares maternal/newborn outcomes after IOL at 40 GW (IOL40) or 41 GW (IOL41) versus spontaneous onset of labour (SOL).

Methods

Data were extracted from the routine prospective individual patient database of the Soysa Teaching Hospital for Women, Colombo. IOL and SOL groups were compared using logistic regression.

Results

Of 13,670 deliveries, 2359 (17.4%) were singleton and low risk at 40 or 41 GW. Of these, 456 (19.3%) women underwent IOL40, 318 (13.5%) IOL41, and 1585 (67.2%) SOL. Both IOL40 and IOL41 were associated with an increased risk of any maternal/newborn negative outcomes (OR = 2.21, 95%CI = 1.75–2.77, p < 0.001 and OR = 1.91, 95%CI = 1.47–2.48, p < 0.001 respectively), maternal complications (OR = 2.18, 95%CI = 1.71–2.77, p < 0.001 and OR = 2.34, 95%CI = 1.78–3.07, p < 0.001 respectively) and caesarean section (OR = 2.75, 95%CI = 2.07–3.65, p < 0.001 and OR = 3.01, 95%CI = 2.21–4.12, p < 0.001 respectively). Results did not change in secondary and sensitivity analyses.

Conclusions

Both IOL groups were associated with higher risk of negative outcomes compared to SOL. Findings, potentially explained by selection bias, local IOL protocols and CS practices, are valuable for Sri Lanka, particularly given contradictory findings from other settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04800-1.

Induction of labour in pregnant individuals with obesity

People with obesity may require induction of labour (IoL) due to a higher incidence of pre-existing comorbidities and pregnancy complications, as well as to prevent post-term pregnancies and late-term stillbirths. IoL at 39-40 weeks is associated with fewer caesarean births and lower morbidity for the pregnant person and neonate when compared with expectant management. Ensuring the success and safety of IoL in people with obesity requires adherence to evidence-based protocols for the management of labour induction and augmentation. Cervical ripening as well as the latent and active phases of labour in people with obesity may be considerably prolonged, requiring higher cumulative doses of oxytocin. This should be guided by intrauterine pressure catheters and early provision of neuraxial analgesia, where possible. There is insufficient evidence to recommend one method of IoL over another. The need for higher doses of prostaglandins and concurrent agents for cervical ripening should be studied in prospective studies.

Can we improve our ability to interpret category II fetal heart rate tracings using additional clinical parameters?

OBJECTIVES

This study examined predictive factors, in addition to Category II Fetal Herat Rate (FHR) monitoring that might imply fetal acidosis and risk of asphyxia.

METHODS

This retrospective cohort study compared three groups of patients with Category II FHR monitoring indicating need for imminent delivery. Groups were divided based on fetal cord blood pH: pH≤7.0, 7.0<pH<7.2 and pH≥7.2. Demographics, medical history, delivery data and early neonatal outcomes were reviewed.

RESULTS

The cohort included 417 women. Nine (2.2%) had cord pH≤7.0, 105 (25.2%) pH 7.0 to 7.2 and 303 (72.6%) ad pH≥7.2. Background characteristics, pregnancy follow-up and intrauterine fetal evaluation prior to delivery were similar in all groups. As expected, more patients in the low pH group had cesarean section (55.6%), than vaginal delivery or vacuum extraction (p=0.02). Five-minute Apgar scores were similar in all groups.

CONCLUSIONS

This retrospective study did not detect a specific parameter that could help predict the prognosis of fetal acidosis and risk of asphyxia. As we only included patients with a Category II tracing that was worrisome enough to lead to imminent delivery, it is reasonable to believe that this is due to patient selection, meaning that when the Category II FHR results in decision for prompt delivery, there is no added value in additional clinical characteristics. The evaluation should be expanded to all patients with Category II tracing for better interpretation tools for Category II FHR monitors, as well as a larger study population.

Quality appraisal of systematic reviews on methods of labour induction: a systematic review

PURPOSE

Induction of labour has become more common over the last decade, together with an increase in the number of systematic reviews of the subject. However, with multiple systematic reviews it is necessary to evaluate the methodological rigor to ensure the reliability of conclusions and recommendations for clinical practice. Therefore, the aim of this study was to appraise the quality of systematic reviews that examined the efficacy and/or safety of labour induction methods.

METHODS

An electronic search of MEDLINE, Embase, and the Cochrane Library from 2000 to 2020 was conducted. Study selection, data extraction and quality assessment were conducted using A Measurement Tool to Assess Systematic Reviews (AMSTAR) by two independent reviewers, in duplicate.

RESULTS

The search identified 387 publications, of which 48 studies (13%) met the a priori inclusion criteria. No significant relationships were found between study quality and number of citations, journal impact factor, or publication year.

CONCLUSION

Methodological quality for systematic reviews on the induction of labour were ranked as moderate with no significant changes in quality over the past 2 decades. Publication characteristics are not significantly associated with methodological quality, indicating that healthcare professionals should critically appraise studies before applying them to practice.

[Prolonged and post-term pregnancies: a regional survey of French clinical practices]

OBJECTIVE

To assess professional practices of prolonged and post-term pregnancies in accordance to French guidelines. The secondary outcome was to evaluate neonatal and maternal morbidity during prolonged pregnancy.

METHODS

Descriptive retrospective study was conducted in the 23 maternity hospitals of perinatal network between September and December 2018. The inclusion criterion was a birth term of≥41⁺⁰ weeks of gestation. Primary outcome was conformity to the national guidelines based on 10 items (conformity score≥80%). The secondary outcome was a composite criteria of neonatal morbidity (ventilation, resuscitation and/or Apgar score<7 at 5minutes) and maternal morbidity (obstetrical anal sphincter injury and/or postpartum hemorrhage).

RESULTS

A total of 596 patients were included and the conformity was obtained in 65.3% of cases. Inconsistent criteria were amniotic fluid evaluation by the deepest vertical pocket (46.8%, n=279), and information of patients on prolonged pregnancy management (14.8%, n=88). Adverse perinatal outcome occurred for 40 newborns (6.0%) with shoulder dystocia (OR=5.2; CI 95%: 1.4-19.7) as a principal risk factor. Maternal morbidity outcome occurred in 70 cases (10.6%) primarily with increase in labour duration (OR=1.1 by hour of labour; CI 95%: 1.02-1.24) and prior caesarian section (OR=4.4; CI 95%: 1.8-11.0).

CONCLUSIONS

Management of prolonged and post-term pregnancies matching with the French national guidelines. Points of improvement are amniotic fluid evaluation at term by a single deepest vertical pocket, and the information about induction of labour at term.

Feasibility study protocol of a pragmatic, randomised controlled pilot trial: membrane sweeping to prevent post-term pregnancy-the MILO Study

BACKGROUND

Post-term pregnancy is associated with an increased risk of maternal complications, respiratory distress and trauma to the neonate. Amniotic membrane sweeping has been recommended as a simple procedure to promote the spontaneous onset of labour. However, despite its widespread use, there is an absence of evidence on (a) its effectiveness and (b) its optimal timing and frequency. The primary aim of the MILO Study is to inform the optimal design of a future definitive randomised trial to evaluate the effectiveness (including optimal timing and frequency) of membrane sweeping to prevent post-term pregnancy. We will also assess the acceptability and feasibility of the proposed trial interventions to clinicians and women (through focus group interviews).

METHODS/DESIGN

Multicentre, pragmatic, parallel-group, pilot randomised controlled trial with an embedded factorial design. Pregnant women with a live, singleton foetus ≥ 38 weeks gestation; cephalic presentation; longitudinal lie; intact membranes; English speaking and ≥ 18 years of age will be randomised in a 2:1 ratio to membrane sweep versus no membrane sweep. Women allocated randomly to a sweep will then be randomised further (factorial component) to early (from 39 weeks) versus late (from 40 weeks) sweep commencement and a single versus weekly sweep. The proposed feasibility study consists of four work packages, i.e. (1) a multicentre, pilot randomised trial; (2) a health economic analysis; (3) a qualitative study; and (4) a study within the host trial (a SWAT). Outcomes to be collected include recruitment and retention rates, compliance with protocol, randomisation and allocation processes, attrition rates and cost-effectiveness. Focus groups will be held with women and clinicians to explore the acceptability and feasibility of the proposed intervention, study procedures and perceived barriers and enablers to recruitment.

DISCUSSION

The primary aim of the MILO Study is to inform the optimal design of a future definitive randomised trial to evaluate the effectiveness (including optimal timing and frequency) of membrane sweeping to prevent post-term pregnancy. Results will inform whether and how the design of the definitive trial as originally envisaged should be delivered or adapted.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04307199 . Registered on 12 March 2020.

Induction of labour at 41 weeks or expectant management until 42 weeks: A systematic review and an individual participant data meta-analysis of randomised trials

BACKGROUND

The risk of perinatal death and severe neonatal morbidity increases gradually after 41 weeks of pregnancy. Several randomised controlled trials (RCTs) have assessed if induction of labour (IOL) in uncomplicated pregnancies at 41 weeks will improve perinatal outcomes. We performed an individual participant data meta-analysis (IPD-MA) on this subject.

METHODS AND FINDINGS

We searched PubMed, Excerpta Medica dataBASE (Embase), The Cochrane Library, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and PsycINFO on February 21, 2020 for RCTs comparing IOL at 41 weeks with expectant management until 42 weeks in women with uncomplicated pregnancies. Individual participant data (IPD) were sought from eligible RCTs. Primary outcome was a composite of severe adverse perinatal outcomes: mortality and severe neonatal morbidity. Additional outcomes included neonatal admission, mode of delivery, perineal lacerations, and postpartum haemorrhage. Prespecified subgroup analyses were conducted for parity (nulliparous/multiparous), maternal age (<35/≥35 years), and body mass index (BMI) (<30/≥30). Aggregate data meta-analysis (MA) was performed to include data from RCTs for which IPD was not available. From 89 full-text articles, we identified three eligible RCTs (n = 5,161), and two contributed with IPD (n = 4,561). Baseline characteristics were similar between the groups regarding age, parity, BMI, and higher level of education. IOL resulted overall in a decrease of severe adverse perinatal outcome (0.4% [10/2,281] versus 1.0% [23/2,280]; relative risk [RR] 0.43 [95% confidence interval [CI] 0.21 to 0.91], p-value 0.027, risk difference [RD] -57/10,000 [95% CI -106/10,000 to -8/10,000], I2 0%). The number needed to treat (NNT) was 175 (95% CI 94 to 1,267). Perinatal deaths occurred in one (<0.1%) versus eight (0.4%) pregnancies (Peto odds ratio [OR] 0.21 [95% CI 0.06 to 0.78], p-value 0.019, RD -31/10,000, [95% CI -56/10,000 to -5/10,000], I2 0%, NNT 326, [95% CI 177 to 2,014]) and admission to a neonatal care unit ≥4 days occurred in 1.1% (24/2,280) versus 1.9% (46/2,273), (RR 0.52 [95% CI 0.32 to 0.85], p-value 0.009, RD -97/10,000 [95% CI -169/10,000 to -26/10,000], I2 0%, NNT 103 [95% CI 59 to 385]). There was no difference in the rate of cesarean delivery (10.5% versus 10.7%; RR 0.98, [95% CI 0.83 to 1.16], p-value 0.81) nor in other important perinatal, delivery, and maternal outcomes. MA on aggregate data showed similar results. Prespecified subgroup analyses for the primary outcome showed a significant difference in the treatment effect (p = 0.01 for interaction) for parity, but not for maternal age or BMI. The risk of severe adverse perinatal outcome was decreased for nulliparous women in the IOL group (0.3% [4/1,219] versus 1.6% [20/1,264]; RR 0.20 [95% CI 0.07 to 0.60], p-value 0.004, RD -127/10,000, [95% CI -204/10,000 to -50/10,000], I2 0%, NNT 79 [95% CI 49 to 201]) but not for multiparous women (0.6% [6/1,219] versus 0.3% [3/1,264]; RR 1.59 [95% CI 0.15 to 17.30], p-value 0.35, RD 27/10,000, [95% CI -29/10,000 to 84/10,000], I2 55%). A limitation of this IPD-MA was the risk of overestimation of the effect on perinatal mortality due to early stopping of the largest included trial for safety reasons after the advice of the Data and Safety Monitoring Board. Furthermore, only two RCTs were eligible for the IPD-MA; thus, the possibility to assess severe adverse neonatal outcomes with few events was limited.

CONCLUSIONS

In this study, we found that, overall, IOL at 41 weeks improved perinatal outcome compared with expectant management until 42 weeks without increasing the cesarean delivery rate. This benefit is shown only in nulliparous women, whereas for multiparous women, the incidence of mortality and morbidity was too low to demonstrate any effect. The magnitude of risk reduction of perinatal mortality remains uncertain. Women with pregnancies approaching 41 weeks should be informed on the risk differences according to parity so that they are able to make an informed choice for IOL at 41 weeks or expectant management until 42 weeks. Study Registration: PROSPERO CRD42020163174.

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.

What women want and why. Women's preferences for induction of labour or expectant management in late-term pregnancy

BACKGROUND

Both induction of labour at 41 weeks and expectant management until 42 weeks are common management strategies in low-risk pregnancy since there is no consensus on the optimal timing of induction in late-term pregnancy for the prevention of adverse outcomes. Our aim was to explore maternal preference for either strategy and the influence on quality of life and maternal anxiety on this preference.

METHODS

Obstetrical low-risk women with an uncomplicated pregnancy were eligible when they reached a gestational age of 41 weeks. They were asked to fill in questionnaires on quality of life (EQ6D) and anxiety (STAI-state). Reasons of women's preferences for either induction or expectant management were explored in a semi-structured questionnaire containing open ended questions.

RESULTS

Of 782 invited women 604 (77.2%) responded. Induction at 41 weeks was preferred by 44.7% (270/604) women, 42.1% (254/604) preferred expectant management until 42 weeks, while 12.2% (74/604) of women did not have a preference. Women preferring induction reported significantly more problems regarding quality of life and were more anxious than women preferring expectant management (p<0.001). Main reasons for preferring induction of labour were: "safe feeling" (41.2%), "pregnancy taking too long" (35.4%) and "knowing what to expect" (18.6%). For women preferring expectant management, the main reason was "wish to give birth as natural as possible" (80.3%).

CONCLUSION

Women's preference for induction of labour or a policy of expectant management in late-term pregnancy is influenced by anxiety, quality of life problems (induction), the presence of a wish for natural birth (expectant management), and a variety of additional reasons. This variation in preferences and motivations suggests that there is room for shared decision making in the management of late-term pregnancy.