Induction of labour for improving birth outcomes for women at or beyond term

Women's experiences of decision-making and attitudes in relation to induction of labour: A survey study

BACKGROUND

Rates of induction of labour have been increasing globally to up to one in three pregnancies in many high-income countries. Although guidelines around induction, and strength of the underlying evidence, vary considerably by indication, shared decision-making is increasingly recognised as key. The aim of this study was to identify women's mode of birth preferences and experiences of shared decision-making for induction of labour.

METHOD

An antenatal survey of women booked for an induction at eight Sydney hospitals was conducted. A bespoke questionnaire was created assessing women's demographics, indication for induction, pregnancy model of care, initial birth preferences, and their experience of the decision-making process.

RESULTS

Of 189 survey respondents (58% nulliparous), major reported reasons for induction included prolonged pregnancy (38%), diabetes (25%), and suspected fetal growth restriction (8%). Most respondents (72%) had hoped to labour spontaneously. Major findings included 19% of women not feeling like they had a choice about induction of labour, 26% not feeling adequately informed (or uncertain if informed), 17% not being given alternatives, and 30% not receiving any written information on induction of labour. Qualitative responses highlight a desire of women to be more actively involved in decision-making.

CONCLUSION

A substantial minority of women did not feel adequately informed or prepared, and indicated they were not given alternatives to induction. Suggested improvements include for face-to-face discussions to be supplemented with written information, and for shared decision-making interventions, such as the introduction of decision aids and training, to be implemented and evaluated.

Membrane sweeping for induction of labour

BACKGROUND

Induction of labour involves stimulating uterine contractions artificially to promote the onset of labour. There are several pharmacological, surgical and mechanical methods used to induce labour. Membrane sweeping is a mechanical technique whereby a clinician inserts one or two fingers into the cervix and using a continuous circular sweeping motion detaches the inferior pole of the membranes from the lower uterine segment. This produces hormones that encourage effacement and dilatation potentially promoting labour. This review is an update to a review first published in 2005.

OBJECTIVES

To assess the effects and safety of membrane sweeping for induction of labour in women at or near term (≥ 36 weeks' gestation).

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (25 February 2019), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (25 February 2019), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing membrane sweeping used for third trimester cervical ripening or labour induction with placebo/no treatment or other methods listed on a predefined list of labour induction methods. Cluster-randomised trials were eligible, but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, risk of bias and extracted data. Data were checked for accuracy. Disagreements were resolved by discussion, or by including a third review author. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 44 studies (20 new to this update), reporting data for 6940 women and their infants. We used random-effects throughout. Overall, the risk of bias was assessed as low or unclear risk in most domains across studies. Evidence certainty, assessed using GRADE, was found to be generally low, mainly due to study design, inconsistency and imprecision. Six studies (n = 1284) compared membrane sweeping with more than one intervention and were thus included in more than one comparison. No trials reported on the outcomes uterine hyperstimulation with/without fetal heart rate (FHR) change, uterine rupture or neonatal encephalopathy. Forty studies (6548 participants) compared membrane sweeping with no treatment/sham Women randomised to membrane sweeping may be more likely to experience: · spontaneous onset of labour (average risk ratio (aRR) 1.21, 95% confidence interval (CI) 1.08 to 1.34, 17 studies, 3170 participants, low-certainty evidence). but less likely to experience: · induction (aRR 0.73, 95% CI 0.56 to 0.94, 16 studies, 3224 participants, low-certainty evidence); There may be little to no difference between groups for: · caesareans (aRR 0.94, 95% CI 0.85 to 1.04, 32 studies, 5499 participants, moderate-certainty evidence); · spontaneous vaginal birth (aRR 1.03, 95% CI 0.99 to 1.07, 26 studies, 4538 participants, moderate-certainty evidence); · maternal death or serious morbidity (aRR 0.83, 95% CI 0.57 to 1.20, 17 studies, 2749 participants, low-certainty evidence); · neonatal perinatal death or serious morbidity (aRR 0.83, 95% CI 0.59 to 1.17, 18 studies, 3696 participants, low-certainty evidence). Four studies reported data for 480 women comparing membrane sweeping with vaginal/intracervical prostaglandins There may be little to no difference between groups for the outcomes: · spontaneous onset of labour (aRR, 1.24, 95% CI 0.98 to 1.57, 3 studies, 339 participants, low-certainty evidence); · induction (aRR 0.90, 95% CI 0.56 to 1.45, 2 studies, 157 participants, low-certainty evidence); · caesarean (aRR 0.69, 95% CI 0.44 to 1.09, 3 studies, 339 participants, low-certainty evidence); · spontaneous vaginal birth (aRR 1.12, 95% CI 0.95 to 1.32, 2 studies, 252 participants, low-certainty evidence); · maternal death or serious morbidity (aRR 0.93, 95% CI 0.27 to 3.21, 1 study, 87 participants, low-certainty evidence); · neonatal perinatal death or serious morbidity (aRR 0.40, 95% CI 0.12 to 1.33, 2 studies, 269 participants, low-certainty evidence). One study, reported data for 104 women, comparing membrane sweeping with intravenous oxytocin +/- amniotomy There may be little to no difference between groups for: · spontaneous onset of labour (aRR 1.32, 95% CI 88 to 1.96, 1 study, 69 participants, low-certainty evidence); · induction (aRR 0.51, 95% CI 0.05 to 5.42, 1 study, 69 participants, low-certainty evidence); · caesarean (aRR 0.69, 95% CI 0.12 to 3.85, 1 study, 69 participants, low-certainty evidence); · maternal death or serious morbidity was reported on, but there were no events. Two studies providing data for 160 women compared membrane sweeping with vaginal/oral misoprostol There may be little to no difference between groups for: · caesareans (RR 0.82, 95% CI 0.31 to 2.17, 1 study, 96 participants, low-certainty evidence). One study providing data for 355 women which compared once weekly membrane sweep with twice-weekly membrane sweep and a sham procedure There may be little to no difference between groups for: · induction (RR 1.19, 95% CI 0.76 to 1.85, 1 study, 234 participants, low-certainty); · caesareans (RR 0.93, 95% CI 0.60 to 1.46, 1 study, 234 participants, low-certainty evidence); · spontaneous vaginal birth (RR 1.00, 95% CI 0.86 to 1.17, 1 study, 234 participants, moderate-certainty evidence); · maternal death or serious maternal morbidity (RR 0.78, 95% CI 0.30 to 2.02, 1 study, 234 participants, low-certainty evidence); · neonatal death or serious neonatal perinatal morbidity (RR 2.00, 95% CI 0.18 to 21.76, 1 study, 234 participants, low-certainty evidence); We found no studies that compared membrane sweeping with amniotomy only or mechanical methods. Three studies, providing data for 675 women, reported that women indicated favourably on their experience of membrane sweeping with one study reporting that 88% (n = 312) of women questioned in the postnatal period would choose membrane sweeping in the next pregnancy. Two studies reporting data for 290 women reported that membrane sweeping is more cost-effective than using prostaglandins, although more research should be undertaken in this area.

AUTHORS' CONCLUSIONS

Membrane sweeping may be effective in achieving a spontaneous onset of labour, but the evidence for this was of low certainty. When compared to expectant management, it potentially reduces the incidence of formal induction of labour. Questions remain as to whether there is an optimal number of membrane sweeps and timings and gestation of these to facilitate induction of labour.

Capacity and patient flow planning in post-term pregnancy outpatient clinics: a computer simulation modelling study

BACKGROUND

The demand for a large Norwegian hospital's post-term pregnancy outpatient clinic has increased substantially over the last 10 years due to changes in the hospital's catchment area and to clinical guidelines. Planning the clinic is further complicated due to the high did not attend rates as a result of women giving birth. The aim of this study is to determine the maximum number of women specified clinic configurations, combination of specified clinic resources, can feasibly serve within clinic opening times.

METHODS

A hybrid agent based discrete event simulation model of the clinic was used to evaluate alternative configurations to gain insight into clinic planning and to support decision making. Clinic configurations consisted of six factors: X0: Arrivals. X1: Arrival pattern. X2: Order of midwife and doctor consultations. X3: Number of midwives. X4: Number of doctors. X5: Number of cardiotocography (CTGs) machines. A full factorial experimental design of the six factors generated 608 configurations.

RESULTS

Each configuration was evaluated using the following measures: Y1: Arrivals. Y2: Time last woman checks out. Y3: Women's length of stay (LoS). Y4: Clinic overrun time. Y5: Midwife waiting time (WT). Y6: Doctor WT. Y7: CTG connection WT. Optimisation was used to maximise X0 with respect to the 32 combinations of X1-X5. Configuration 0a, the base case Y1 = 7 women and Y3 = 102.97 [0.21] mins. Changing the arrival pattern (X1) and the order of the midwife and doctor consultations (X2) configuration 0d, where X3, X4, X5 = 0a, Y1 = 8 woman and Y3 86.06 [0.10] mins.

CONCLUSIONS

The simulation model identified the availability of CTG machines as a bottleneck in the clinic, indicated by the WT for CTG connection effect on LoS. One additional CTG machine improved clinic performance to the same degree as an extra midwife and an extra doctor. The simulation model demonstrated significant reductions to LoS can be achieved without additional resources, by changing the clinic pathway and scheduling of appointments. A more general finding is that a simulation model can be used to identify bottlenecks, and efficient ways of restructuring an outpatient clinic.

A systematic scoping review of clinical indications for induction of labour

BACKGROUND

The proportion of women undergoing induction of labour (IOL) has risen in recent decades, with significant variation within countries and between hospitals. The aim of this study was to review research supporting indications for IOL and determine which indications are supported by evidence and where knowledge gaps exist.

METHODS

A systematic scoping review of quantitative studies of common indications for IOL. For each indication, we included systematic reviews/meta-analyses, randomised controlled trials (RCTs), cohort studies and case control studies that compared maternal and neonatal outcomes for different modes or timing of birth. Studies were identified via the databases PubMed, Maternity and Infant Care, CINAHL, EMBASE, and ClinicalTrials.gov from between April 2008 and November 2019, and also from reference lists of included studies. We identified 2554 abstracts and reviewed 300 full text articles. The quality of included studies was assessed using the RoB 2.0, the ROBINS-I and the ROBIN tool.

RESULTS

68 studies were included which related to post-term pregnancy (15), hypertension/pre-eclampsia (15), diabetes (9), prelabour rupture of membranes (5), twin pregnancy (5), suspected fetal compromise (4), maternal elevated body mass index (BMI) (4), intrahepatic cholestasis of pregnancy (3), suspected macrosomia (3), fetal gastroschisis (2), maternal age (2), and maternal cardiac disease (1). Available evidence supports IOL for women with post-term pregnancy, although the evidence is weak regarding the timing (41 versus 42 weeks), and for women with hypertension/preeclampsia in terms of improved maternal outcomes. For women with preterm premature rupture of membranes (24-37 weeks), high-quality evidence supports expectant management rather than IOL/early birth. Evidence is weakly supportive for IOL in women with term rupture of membranes. For all other indications, there were conflicting findings and/or insufficient power to provide definitive evidence.

CONCLUSIONS

While for some indications, IOL is clearly recommended, a number of common indications for IOL do not have strong supporting evidence. Overall, few RCTs have evaluated the various indications for IOL. For conditions where clinical equipoise regarding timing of birth may still exist, such as suspected macrosomia and elevated BMI, researchers and funding agencies should prioritise studies of sufficient power that can provide quality evidence to guide care in these situations.

Clinical interventions that influence vaginal birth after cesarean delivery rates: Systematic Review & Meta-Analysis

BACKGROUND

To systematically review the literature on clinical interventions that influence vaginal birth after cesarean (VBAC) rates.

METHODS

We searched Ovid Medline, Ovid Embase, Wiley Cochrane Library, CINAHL via EBSCOhost; and Ovid PsycINFO. Additional studies were identified by searching for clinical trial records, conference proceedings and dissertations. Limits were applied for language (English and French) and year of publication (1985 to present). Two reviewers independently screened comparative studies (randomized or non-randomized controlled trials, and observational designs) according to a priori eligibility criteria: women with prior cesarean sections; any clinical intervention or exposure intended to increase the VBAC rate; any comparator; and, outcomes reporting VBAC, uterine rupture and uterine dehiscence rates. One reviewer extracted data and a second reviewer verified for accuracy. Meta-analysis was conducted using Mantel-Haenszel (random effects model) relative risks (VBAC rate) and risk differences (uterine rupture and dehiscence). Two reviewers independently conducted methodological quality assessments using the Mixed Methods Appraisal Tool (MMAT).

RESULTS

Twenty-nine studies (six trials and 23 cohorts) examined different clinical interventions affecting rates of vaginal deliveries among women with a prior cesarean delivery (CD). Methodological quality was good overall for the trials; however, concerns among the cohort studies regarding selection bias, comparability of groups and outcome measurement resulted in higher risk of bias. Interventions for labor induction, with or without cervical ripening, included pharmacologic (oxytocin, prostaglandins, misoprostol, mifepristone, epidural analgesia), non-pharmacologic (membrane sweep, amniotomy, balloon devices), and combined (pharmacologic and non-pharmacologic). Single studies with small sample sizes and event rates contributed to most comparisons, with no clear differences between groups on rates of VBAC, uterine rupture and uterine dehiscence.

CONCLUSIONS

This systematic review evaluated clinical interventions directed at increasing the rate of vaginal delivery among women with a prior CD and found low to very low certainty in the body of evidence for cervical ripening and/or labor induction techniques. There is insufficient high-quality evidence to inform optimal clinical interventions among women attempting a trial of labor after a prior CD.

Induction of labour at 41 weeks versus expectant management and induction of labour at 42 weeks (SWEdish Post-term Induction Study, SWEPIS): multicentre, open label, randomised, superiority trial

OBJECTIVE

To evaluate if induction of labour at 41 weeks improves perinatal and maternal outcomes in women with a low risk pregnancy compared with expectant management and induction of labour at 42 weeks.

DESIGN

Multicentre, open label, randomised controlled superiority trial.

SETTING

14 hospitals in Sweden, 2016-18.

PARTICIPANTS

2760 women with a low risk uncomplicated singleton pregnancy randomised (1:1) by the Swedish Pregnancy Register. 1381 women were assigned to the induction group and 1379 were assigned to the expectant management group.

INTERVENTIONS

Induction of labour at 41 weeks and expectant management and induction of labour at 42 weeks.

MAIN OUTCOME MEASURES

The primary outcome was a composite perinatal outcome including one or more of stillbirth, neonatal mortality, Apgar score less than 7 at five minutes, pH less than 7.00 or metabolic acidosis (pH <7.05 and base deficit >12 mmol/L) in the umbilical artery, hypoxic ischaemic encephalopathy, intracranial haemorrhage, convulsions, meconium aspiration syndrome, mechanical ventilation within 72 hours, or obstetric brachial plexus injury. Primary analysis was by intention to treat.

RESULTS

The study was stopped early owing to a significantly higher rate of perinatal mortality in the expectant management group. The composite primary perinatal outcome did not differ between the groups: 2.4% (33/1381) in the induction group and 2.2% (31/1379) in the expectant management group (relative risk 1.06, 95% confidence interval 0.65 to 1.73; P=0.90). No perinatal deaths occurred in the induction group but six (five stillbirths and one early neonatal death) occurred in the expectant management group (P=0.03). The proportion of caesarean delivery, instrumental vaginal delivery, or any major maternal morbidity did not differ between the groups.

CONCLUSIONS

This study comparing induction of labour at 41 weeks with expectant management and induction at 42 weeks does not show any significant difference in the primary composite adverse perinatal outcome. However, a reduction of the secondary outcome perinatal mortality is observed without increasing adverse maternal outcomes. Although these results should be interpreted cautiously, induction of labour ought to be offered to women no later than at 41 weeks and could be one (of few) interventions that reduces the rate of stillbirths.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN26113652.

Mode of delivery among nulliparous women with single, cephalic, term pregnancies: The WHO global survey on maternal and perinatal health, 2004-2008

OBJECTIVE

To determine risk factors associated with cesarean delivery among nulliparous women in spontaneous labor with a single, cephalic, term pregnancy (Robson group 1).

METHODS

Data were assessed from the WHO Global Survey of Maternal and Perinatal Health conducted in 2004-2008.

RESULTS

Among 82 280 women in Robson group 1, 67 698 (82.3%) had vaginal and 14 578 (17.7%) had cesarean delivery. In adjusted analyses, maternal factors associated with cesarean included age older than 18 years, being overweight or obese, being married or cohabitating, attending four prenatal visits or more, and being medically high risk (P<0.001). Women who were obstetrically high risk, referred during labor, or at 39 gestational weeks or more were also more likely to undergo cesarean (all P<0.001). Facility-level factors associated with cesarean were availability of an anesthesia service 24/7, being a teaching facility, requirement of fees for cesarean, availability of electronic fetal monitoring, and having providers skilled in operative vaginal delivery (all P<0.01).

CONCLUSION

The analysis highlights the importance of maintaining a healthy pre-pregnancy and pregnancy weight, optimizing management of women with medical problems, and ensuring clear referral mechanisms for women with intrapartum complications. The association between fees and cesarean delivery warrants further exploration.

Recent advances in the induction of labor

The rate of labor induction is steadily increasing and, in industrialized countries, approximately one out of four pregnant women has their labor induced. Induction of labor should be considered when the benefits of prompt vaginal delivery outweigh the maternal and/or fetal risks of waiting for the spontaneous onset of labor. However, this procedure is not free of risks, which include an increase in operative vaginal or caesarean delivery and excessive uterine activity with risk of fetal heart rate abnormalities. A search for "Induction of Labor" retrieves more than 18,000 citations from 1844 to the present day. The aim of this review is to summarize the controversies concerning the indications, the methods, and the tools for evaluating the success of the procedure, with an emphasis on the scientific evidence behind each.

Induction of labor and postpartum blood loss

BACKGROUND

To analyze blood loss after delivery in women with induction of labor compared to women with spontaneous onset of labor.

METHODS

In this secondary analysis of a prospective cohort study investigating postpartum hemorrhage, 965 deliveries were analyzed including 380 women with induction of labor (39%) between 2015 and 2016. Primary outcome parameters were rate of postpartum hemorrhage, estimated blood loss and post-partum decrease in hemoglobin.

RESULTS

Rates of postpartum hemorrhage and estimated blood loss were not significantly different in women with induction of labor. Women with induction of labor had a significantly reduced decrease in hemoglobin after delivery. In the multivariate linear regression analysis, induction of labor remained associated with reduced decrease in hemoglobin. Secondary maternal and neonatal outcomes were unaffected.

CONCLUSIONS

Induction of labor is not associated with increased blood loss after delivery and should not be regarded as a risk factor for postpartum hemorrhage.

Induction of labour indications and timing: A systematic analysis of clinical guidelines

BACKGROUND

There is widespread and some unexplained variation in induction of labour rates between hospitals. Some practice variation may stem from variability in clinical guidelines. This review aimed to identify to what extent induction of labour guidelines provide consistent recommendations in relation to reasons for, and timing of, induction of labour and ascertain whether inconsistencies can be explained by variability guideline quality.

METHOD

We conducted a systematic search of national and international English-language guidelines published between 2008 and 2018. General induction of labour guidelines and condition-specific guidelines containing induction of labour recommendations were searched. Guidelines were reviewed and extracted independently by two reviewers. Guideline quality was assessed using the Appraisal of Guidelines for Research and Evaluation II Instrument.

FINDINGS

Forty nine guidelines of varying quality were included. Indications where guidelines had mostly consistent advice included prolonged pregnancy (induction between 41 and 42 weeks), preterm premature rupture of membranes, and term preeclampsia (induction when preeclampsia diagnosed ≥37 weeks). Guidelines were also consistent in agreeing on decreased fetal movements and oligohydramnios as valid indications for induction, although timing recommendations were absent or inconsistent. Common indications where there was little consensus on validity and/or timing of induction included gestational diabetes, fetal macrosomia, elevated maternal body mass index, and twin pregnancy.

CONCLUSION

Substantial variation in clinical practice guidelines for indications for induction exists. As guidelines rated of similar quality presented conflicting recommendations, guideline variability was not explained by guideline quality. Guideline variability may partly account for unexplained variation in induction of labour rates.

NICU Admissions for Meconium Aspiration Syndrome before and after a National Resuscitation Program Suctioning Guideline Change

The Textbook of Neonatal Resuscitation, seventh edition, does not suggest routine endotracheal suctioning for non-vigorous infants born through meconium-stained amniotic fluid. We compared 301,150 infants at ≥35 weeks' gestational age inborn at 311 Vermont Oxford Network member centers in the United States (U.S.) and admitted to neonatal intensive care units (NICU) who were born before (2013 to 2015) and after (2017) the guideline change. Logistic regression models adjusting for clustering of infants within centers were used to calculate risk ratios. NICU admissions for infants with a diagnosis of meconium aspiration syndrome (MAS) decreased from 1.8% to 1.5% (risk ratio: 0.82; 95% confidence interval: 0.68, 0.97) and delivery room endotracheal suctioning in this group decreased from 57.0% to 28.9% (0.51; 0.41, 0.62). Treatment with conventional or high frequency ventilation, inhaled nitric oxide, or extracorporeal membrane oxygenation remained unchanged 42.3% vs. 40.3% (0.95; 0.80, 1.13) among infants with MAS and 9.1% vs. 8.2% (0.91; 0.87, 0.95) among infants without MAS. The use of surfactant among infants with MAS increased from 24.6% to 30% (1.22; 1.02, 1.48). Mortality (2.6 to 2.9%, 1.12; 0.74, 1.69) and moderate/severe hypoxic-ischemic encephalopathy (5.4 to 6.8%, 1.24; 0.91, 1.69) increased slightly in 2017. Subgroup analyses of infants with 1 min Apgar scores of ≤3 found similar results. While NICU admissions for MAS and tracheal suctioning decreased after the introduction of the new guideline with no subsequent increase in severe respiratory distress among infants with and without a MAS diagnosis, limitations in our study preclude inferring that the new guideline is safe or effective.

Increased labor induction and women presenting with decreased or altered fetal movements - a population-based survey

Introduction

Women’s awareness of fetal movements is important as perception of decreased fetal movements can be a sign of a compromised fetus. We aimed to study rate of labor induction in relation to number of times women seek care due to decreased or altered fetal movements during their pregnancy compared to women not seeking such care. Further, we investigated the indication of induction.

Material and methods

A prospective population-based cohort study including all obstetric clinics in Stockholm, Sweden. Questionnaires were distributed to women who sought care due to decreased or altered fetal movements ≥ 28 week’s gestation in 2014, women for whom an examination did not indicate a compromised fetus that required induction of labor or cesarean section when they sought care. Women who gave birth at ≥ 28 weeks’ gestation in 2014 in Stockholm comprises the reference group.

Results

Labor was induced more often among the 2683 women who had sought care due to decreased or altered fetal movements (RR 1.4, 95% CI 1.3–1.5). In women who presented with decreased or altered fetal movements induction of labor occurred more frequently for fetal indication than those with induction of labor and no prior fetal movement presentation (RR 1.6, 95% CI 1.4–1.8). The rate of induction increased with number of times a woman sought care, RR 1.3 for single presentation to 3.2 for five or more.

Conclusions

We studied women seeking care for decreased or altered fetal movements and for whom pregnancy was not terminated with induction or caesarean section. Subsequent (median 20 days), induction of labor and induction for fetal indications were more frequent in this group compared to the group of women with no fetal movement presentations. Among women seeking care for altered or decreased fetal movements, the likelihood of induction of labor increased with frequency of presentation.

Metabolite Changes in Maternal and Fetal Plasma Following Spontaneous Labour at Term in Humans Using Untargeted Metabolomics Analysis: A Pilot Study

The mechanism of human labour remains poorly understood, limiting our ability to manage complications of parturition such as preterm labour and induction of labour. In this study we have investigated the effect of labour on plasma metabolites immediately following delivery, comparing cord and maternal plasma taken from women who laboured spontaneously and delivered vaginally with women who were delivered via elective caesarean section and did not labour. Samples were analysed using ultra high-performance liquid chromatography-tandem mass spectrometry. Welch’s two-sample t-test was used to identify any significant differences. Of 826 metabolites measured, 26.9% (222/826) were significantly altered in maternal plasma and 21.1% (174/826) in cord plasma. Labour involves changes in many maternal organs and poses acute metabolic demands in the uterus and in the fetus and these are reflected in our results. While a proportion of these differences are likely to be secondary to the physiological demands of labour itself, these results present a comprehensive picture of the metabolome in the maternal and fetal circulations at the time of delivery and can be used to guide future studies. We discuss potential causal pathways for labour including endocannabinoids, ceramides, sphingolipids and steroids. Further work is necessary to confirm the specific pathways involved in the spontaneous onset of labour.

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

Current evidence and professional organizations identify letting labor begin on its own as one of the most important strategies for promoting normal, physiologic birth. It also prevents iatrogenic prematurity and the need for high-tech medical interventions required for labor induction. Because the American College of Obstetricians and Gynecologists (ACOG) now states that it is reasonable for obstetric care providers to offer induction at 39 weeks to low-risk nulliparous women, it is more important than ever for childbirth educators to be familiar with best evidence on letting labor begin on its own.

Towards a unified perinatal theory: Reconciling the births-based and fetus-at-risk models of perinatal mortality

BACKGROUND

There is a need to reconcile the opposing perspectives of the births-based and fetuses-at-risk models of perinatal mortality and to formulate a coherent and unified perinatal theory.

METHODS

Information on births in the United States from 2004 to 2015 was used to calculate gestational age-specific perinatal death rates for low- and high-risk cohorts. Cubic splines were fitted to the fetuses-at-risk birth and perinatal death rates, and first and second derivatives were estimated. Births-based perinatal death rates, and fetuses-at-risk birth and perinatal death rates and their derivatives, were examined to identify potential inter-relationships.

RESULTS

The rate of change in the birth rate dictated the pattern of births-based perinatal death rates in a triphasic manner: increases in the first derivative of the birth rate at early gestation corresponded with exponential declines in perinatal death rates, the peak in the first derivative presaged the nadir in perinatal death rates, and late gestation declines in the first derivative coincided with an upturn in perinatal death rates. Late gestation increases in the first derivative of the fetuses-at-risk perinatal death rate matched the upturn in births-based perinatal death rates. Differences in birth rate acceleration/deceleration among low- and high-risk cohorts resulted in intersecting perinatal mortality curves.

CONCLUSION

The first derivative of the birth rate links a cohort's fetuses-at-risk perinatal death rate to its births-based perinatal death rate, and cohort-specific differences in birth rate acceleration/deceleration are responsible for the intersecting perinatal mortality curves paradox. This mechanistic explanation unifies extant models of perinatal mortality and provides diverse insights.

Induction of labour at 41 weeks versus expectant management until 42 weeks (INDEX): multicentre, randomised non-inferiority trial

OBJECTIVE

To compare induction of labour at 41 weeks with expectant management until 42 weeks in low risk women.

DESIGN

Open label, randomised controlled non-inferiority trial.

SETTING

123 primary care midwifery practices and 45 hospitals (secondary care) in the Netherlands, 2012-16.

PARTICIPANTS

1801 low risk women with an uncomplicated singleton pregnancy: randomised to induction (n=900) or to expectant management until 42 weeks (n=901).

INTERVENTIONS

Induction at 41 weeks or expectant management until 42 weeks with induction if necessary.

PRIMARY OUTCOME MEASURES

Primary outcome was a composite of perinatal mortality and neonatal morbidity (Apgar score <7 at five minutes, arterial pH <7.05, meconium aspiration syndrome, plexus brachialis injury, intracranial haemorrhage, and admission to a neonatal intensive care unit (NICU). Secondary outcomes included maternal outcomes and mode of delivery. The null hypothesis that expectant management is inferior to induction was tested with a non-inferiority margin of 2%.

RESULTS

Median gestational age at delivery was 41 weeks+0 days (interquartile range 41 weeks+0 days-41 weeks+1 day) for the induction group and 41 weeks+2 days (41 weeks+0 days-41 weeks+5 days) for the expectant management group. The primary outcome was analysed for both the intention-to-treat population and the per protocol population. In the induction group, 15/900 (1.7%) women had an adverse perinatal outcome versus 28/901 (3.1%) in the expectant management group (absolute risk difference -1.4%, 95% confidence interval -2.9% to 0.0%, P=0.22 for non-inferiority). 11 (1.2%) infants in the induction group and 23 (2.6%) in the expectant management group had an Apgar score <7 at five minutes (relative risk (RR) 0.48, 95% CI 0.23 to 0.98). No infants in the induction group and three (0.3%) in the expectant management group had an Apgar score <4 at five minutes. One fetal death (0.1%) occurred in the induction group and two (0.2%) in the expectant management group. No neonatal deaths occurred. 3 (0.3%) neonates in the induction group versus 8 (0.9%) in the expectant management group were admitted to an NICU (RR 0.38, 95% CI 0.10 to 1.41). No significant difference was found in composite adverse maternal outcomes (induction n=122 (13.6%) v expectant management n=102 (11.3%)) or in caesarean section rate (both groups n=97 (10.8%)).

CONCLUSIONS

This study could not show non-inferiority of expectant management compared with induction of labour in women with uncomplicated pregnancies at 41 weeks; instead a significant difference of 1.4% was found for risk of adverse perinatal outcomes in favour of induction, although the chances of a good perinatal outcome were high with both strategies and the incidence of perinatal mortality, Apgar score <4 at five minutes, and NICU admission low.

TRIAL REGISTRATION

Netherlands Trial Register NTR3431.

Associations between early term and late/post term infants and development of epilepsy: A cohort study

BACKGROUND

While life-long impacts exist for infants born one or two weeks early little evidence exists for those infants born after their due date. However interventions could be used to expedite birth if the risks of continuing the pregnancy are higher than intervening. It is known that the risk of epilepsy in childhood is higher in infants exposed to perinatal compromise and therefore may be useful as a proxy for intrapartum compromise. The aim of this work is to quantify the likelihood of children developing epilepsy based on their gestational age at birth (37-39 weeks or ≥41 weeks).

METHODS

The work is based on term infants born in Sweden between 1983 and 1993 (n = 1,030,168), linked to data on disability pension, child mortality and in-patient epilepsy care. The reference group was defined as infants born at 39 or 40 completed weeks of gestation; compared with infants born at early term (37/38 weeks) or late/post term (41 weeks or more). Primary outcome was defined a-priori as a diagnosis of epilepsy before 20 years of age. Secondary outcomes were childhood mortality (before five years of age), and registered for disability pension before 20 years of age. Logistic regression models were used to assess any association of the outcomes with gestational age at birth.

FINDINGS

In the unadjusted results, infants born 7 or more days after their due date had higher risks of epilepsy and disability pension than the reference group, but similar risks of child death. Early term infants showed higher risks of epilepsy, disability pension and child death. After adjustment for confounders, there remained a higher risk of epilepsy for both early term (OR 1·19 (1·11-1·29)) and late/post term infants (OR 1·13 (1·06-1·22)).

INTERPRETATION

Infants born at 37/38 week or 41 weeks and above, when compared to those born at 39 or 40 weeks gestation, have an increased risk of developing epilepsy. This data could be useful in helping women and care givers make decisions with regard to the timing of induction of labour.