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

The effects of intravenous hydration regimens in nulliparous women undergoing induction of labor: A systematic review and meta-analysis

INTRODUCTION

Labor is both a physiological and physical activity that requires energy expenditure by the woman. Despite this, women are often fasted in labor, with hydration requirements addressed predominantly by intravenous therapy. Little is known about how best to manage this in nulliparous women undergoing induction of labor, who can be prone to lengthy labors. Therefore, we undertook a systematic review and meta-analysis to determine the effects of intravenous hydration regimens on nulliparous women undergoing induction of labor.

MATERIAL AND METHODS

A systematic review and meta-analysis were conducted. Databases searched were PubMed, CINAHL, Embase, Cochrane, Scopus, and Web of Science using the search strategy combination of associated key concepts for intravenous therapy and nulliparous laboring women. The primary outcome was excessive neonatal weight loss. Meta-analyses for categorical outcomes included estimates of odds ratio (OR) and their 95% confidence intervals (CI) calculated; and for continuous outcomes the standardized mean difference, each with its 95% CI. Heterogeneity was assessed visually and by using the χ2 statistic and I2 with significance being set at p < 0.10.

RESULTS

A total of 1512 studies were located and following screening, three studies met the eligibility criteria. No studies reported excessive neonatal weight loss. Increased rates of intravenous therapy (250 mL/h vs. 125 mL/h) during labor were not found to reduce the overall length of labor (mean difference -0.07 h, 95% CI -0.27 to 0.13 h) or reduce cesarean sections (OR 0.74, 95% CI 0.45-1.23), when women were not routinely fasted.

CONCLUSIONS

Our review found no significant improvements for nulliparous women who received higher intravenous fluid volumes when undergoing induction of labor and were not routinely fasted. However, data are limited, and further research is needed.

Severe Perineal Lacerations in Induction of Labor versus Expectant management: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This study aimed to evaluate if induction of labor is associated with an increased risk of severe perineal laceration.

DATA SOURCES

A systematic search was conducted in MEDLINE, Ovid, Scopus, ClinicalTrials.gov, Cochrane Central Register of Controlled Trials, and CINHAL using a combination of keywords and text words related to "induction of labor," "severe perineal laceration," "third-degree laceration," "fourth-degree laceration," and "OASIS" from inception of each database until January 2023.

STUDY ELIGIBILITY CRITERIA

We included all randomized controlled trials comparing induction of labor to expectant management of a singleton, cephalic pregnancy at term gestation that reported rates of severe perineal laceration.

STUDY APPRAISAL AND SYNTHESIS AND METHODS

The primary outcome of interest was severe perineal laceration, defined as third or fourth-degree perineal lacerations. We conducted meta-analyses using the random effects model of DerSimonian and Laird to determine the relative risks or mean differences with 95% confidence intervals. Bias was assessed using guidelines established by Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

A total of 11,187 unique records were screened and ultimately eight randomized controlled trials were included, involving 13,297 patients. There was no statistically significant difference in the incidence of severe perineal lacerations between the induction of labor and expectant management groups (209/6655 (3.1%) vs. 202/6641 (3.0%); relative risk (RR) 1.03, 95% confidence interval (CI) 0.85, 1.26). There was a statistically significant decrease in the rate of cesarean birth (1090/6655 (16.4%) vs. 1230/6641 (18.5%), RR 0.89, 95% CI 0.82, 0.95) and fetal macrosomia (734/2696 (27.2%) vs. 964/2703 (35.7%); RR 0.67: 95% CI 0.50, 0.90) in the induction of labor group.

CONCLUSION

There is no significant difference in the risk of severe perineal lacerations between induction of labor and expectant management in this meta-analysis of randomized controlled trials. Furthermore, there is a lower rate of cesarean births in the induction of labor group, indicating more successful vaginal deliveries with similar rates of severe perineal lacerations. Patients should be counseled that in addition to the known benefits of induction, there is no increased risk of severe perineal lacerations.

[Prostaglandins or cervical balloon for the induction of labor for cervical ripening: A literature review]

OBJECTIVE

Induction of labor in France concerns one birth out of four with 70% of induction starting by cervical ripening, either with a pharmacological (prostaglandins) or a mechanical (balloon) method. This review aims to compare these two methods within current knowledge, using the PRISMA methodology.

METHODS

Trials comparing these two methods, published or unpublished up to July 2023, in French or English were searched for in the PubMed, Cochrane Library and ClinicalTrial.govs datasets. Fifty articles including 10,689 women were selected. The outcomes of interest were those from the Core Outcome Set for trails on Induction of Labour (COSIOL) list: mode of delivery, time from induction-to-birth, maternal and neonatal morbidity, and maternal satisfaction.

RESULT

No differences were observed between the two methods for the mode of delivery or neonatal and maternal morbidity. The time from induction-to-birth was longer for mechanical methods. Those were also associated with a greater need for oxytocin, less uterine hyperstimulation and less instrumental deliveries. Maternal satisfaction was assessed in only nine trials using various scales which made the interpretation of maternal satisfaction.

CONCLUSION

The efficacy of these two induction methods is similar for vaginal delivery, but it remains to be seen which one best meets women's satisfaction criteria.

The role of labor induction in modern obstetrics

A primary goal of obstetrical practice is the optimization of maternal and perinatal health. This goal translates into a seemingly simple assessment with regard to considerations of the timing of delivery: delivery should occur when the benefits are greater than those of continued pregnancy. In the absence of an indication for cesarean delivery, planned delivery is initiated with induction of labor. When medical or obstetrical complications exist, they may guide recommendations regarding the timing of delivery. In the absence of these complications, gestational age also has been used to guide delivery timing, given its association with both maternal and perinatal adverse outcomes. If there is no medical indication, delivery before 39 weeks has been discouraged, given its association with greater chances of adverse perinatal outcomes. Conversely, it has been recommended that delivery occur by 42 weeks of gestation, given the perinatal risks that accrue in the post-term period. Historically, a 39-week induction of labor, particularly for individuals with no previous birth, has not been routinely offered in the absence of medical or obstetrical indications. That approach was based on numerous observational studies that demonstrated an increased risk of cesarean delivery and other adverse outcomes among individuals who underwent labor induction compared to those in spontaneous labor. However, from a management and person-centered-choice perspective, the relevant comparison is between those undergoing planned labor induction at a given time vs those planning to continue pregnancy beyond that time. When individuals have been compared using that rubric-either in observational studies or randomized trials that have been performed in a wide variety of locations and populations- there has not been evidence that induction increases adverse perinatal or maternal outcomes. Conversely, even when the only indication for delivery is the achievement of a full-term gestational age, evidence suggests that multiple different outcomes, including cesarean delivery, hypertensive disorders of pregnancy, neonatal respiratory impairment, and perinatal mortality, are less likely when induction is performed. This information underscores the importance of making the preferences of pregnant individuals for different birth processes and outcomes central to the approach to delivery timing.

Labor induction at 41+0 gestational weeks or expectant management for the nulliparous woman: The Finnish randomized controlled multicenter trial

INTRODUCTION

Neonatal and maternal risks increase in term pregnancy as gestational age advances and become increasingly evident post-term. Management practices of late- and post-term pregnancies vary, and the optimal time point for intervention by labor induction is yet to be determined.

MATERIAL AND METHODS

This randomized controlled trial of 381 nulliparous women with unripe cervices compared labor induction at 41+0 gestational weeks (early induction) with expectant management and labor induction at 41+5 to 42+1 gestational weeks (expectant management). This multicenter study included all five university hospitals and the largest central hospital in Finland. The study period was 2018-2022. Participants were randomized to either early induction (48.8%, n = 186) or expectant management (51.2%, n = 195) with equal randomization ratios of 1:1. This was a superiority trial, and the primary outcomes were rates of cesarean section (CS) and composite of adverse neonatal outcomes. The trial was registered at the ISRCTN registry (ISRCTN83219789, https://doi.org/10.1186/ISRCTN83219789).

RESULTS

The rates of CS (16.7% [n = 31] vs. 24.1% [n = 47], RR 0.7 [95% CI: 0.5-1.0], p = 0.07) and a composite of adverse neonatal outcomes (9.7% [n = 18] vs. 14.4% [n = 28], RR 0.7 [95% CI: 0.4-1.2] p = 0.16) did not significantly differ between the groups, but the operative delivery rate was lower in the early induction group than in the expectant management group (30.6% [n = 57] vs. 45.6% [n = 89], p = 0.003). The rates of hemorrhage ≥1000 mL and neonatal weight ≥4000 g were also lower in the early induction group, as was the vacuum extraction rate in women with vaginal delivery. Of the women with expectant management, 45.6% (n = 89) had spontaneous onset of labor. No perinatal deaths occurred, but one case of eclampsia appeared in the expectant management group.

CONCLUSIONS

Offering labor induction to nulliparous women at 41+0 gestational weeks may decrease the probability of operative delivery, postpartum hemorrhage, and neonatal weight ≥4000 g. However, this study was underpowered to affirm the trends of rising rates of CS and adverse neonatal outcomes in the expectant management group. Thus, expectant management could remain an option for some, as one in two women with expectant management had a spontaneous onset of labor.

Maternal and Perinatal Outcome After Induction of Labor Versus Expectant Management in Low-risk Pregnancies Beyond Term

BACKGROUND/AIM

Due to still controversial discussion regarding appropriate termination of low-risk singleton pregnancies beyond term, this retrospective study aimed to evaluate maternal and perinatal outcomes depending on gestational age and obstetric management.

PATIENTS AND METHODS

This is a retrospective cohort analysis including 3.242 low-risk singleton deliveries at the Department of Obstetrics of the University Hospital of Cologne between 2017 and 2022. According to current national guidelines, the cohort was subdivided into three gestational groups, group 1: 40+0-40+6 weeks, group 2: 40+7-40+10 weeks and group 3>40+10 weeks.

RESULTS

In our cohort, advanced gestational age was associated with higher rates of secondary caesarean sections, lower rates of spontaneous vaginal deliveries, higher rates of meconium-stained amniotic fluid and depressed neonates with APGAR < 7 after 5 min. Analyzing obstetric management, induction of labor significantly increased the rate of secondary sections and reduced the rate of spontaneous deliveries, while the percentage of assistant vaginal deliveries was independent from obstetric management and gestational age. Induction of labor also significantly enhanced the need for tocolytic subpartu and epidural anesthesia and caused higher rates of abnormalities in cardiotocography (CTG), which also resulted in more frequent fetal scalp blood testing; however, the rate of fetal acidosis was independent of both obstetric management and gestational age.

CONCLUSION

Our study supports expectant management of low-risk pregnancies beyond term, as induction of labor increased the rate of secondary sections and did not improve perinatal outcome.

Regional practice variation in induction of labor in the Netherlands: Does it matter? A multilevel analysis of the association between induction rates and perinatal and maternal outcomes

BACKGROUND

Practice variation in healthcare is a complex issue. We focused on practice variation in induction of labor between maternity care networks in the Netherlands. These collaborations of hospitals and midwifery practices are jointly responsible for providing high-quality maternity care. We explored the association between induction rates and maternal and perinatal outcomes.

METHODS

In a retrospective population-based cohort study, we included records of 184,422 women who had a singleton, vertex birth of their first child after a gestation of at least 37 weeks in the years 2016-2018. We calculated induction rates for each maternity care network. We divided networks in induction rate categories: lowest (Q1), moderate (Q2-3) and highest quartile (Q4). We explored the association of these categories with unplanned caesarean sections, unfavorable maternal outcomes and adverse perinatal outcomes using descriptive statistics and multilevel logistic regression analysis corrected for population characteristics.

FINDINGS

The induction rate ranged from 14.3% to 41.1% (mean 24.4%, SD 5.3). Women in Q1 had fewer unplanned caesarean sections (Q1: 10.2%, Q2-3: 12.1%; Q4: 12.8%), less unfavorable maternal outcomes (Q1: 33.8%; Q2-3: 35.7%; Q4: 36.3%) and less adverse perinatal outcomes (Q1: 1.0%; Q2-3: 1.1%; Q4: 1.3%). The multilevel analysis showed a lower unplanned caesarean section rate in Q1 in comparison with reference category Q2-3 (OR 0.83; p = .009). The unplanned caesarean section rate in Q4 was similar to the reference category. No significant associations with unfavorable maternal or adverse perinatal outcomes were observed.

CONCLUSION

Practice variation in labor induction is high in Dutch maternity care networks, with limited association with maternal outcomes and no association with perinatal outcomes. Networks with low induction rates had lower unplanned caesarean section rates compared to networks with moderate rates. Further in-depth research is necessary to understand the mechanisms that contribute to practice variation and the observed association with unplanned caesarean sections.

Comparison of Maternal Labor-Related Complications and Neonatal Outcomes Following Elective Induction of Labor at 39 Weeks of Gestation vs Expectant Management: A Systematic Review and Meta-analysis

Importance

Elective induction of labor at 39 weeks of gestation is common. Thus, there is a need to assess maternal labor-related complications and neonatal outcomes associated with elective induction of labor.

Objective

To examine maternal labor-related complications and neonatal outcomes following elective induction of labor at 39 weeks compared with expectant management.

Data Sources

A systematic review of the literature was conducted using the MEDLINE (Ovid), Embase (Ovid), Cochrane Central Library, World Health Organization, and ClinicalTrials.gov databases and registries to search for articles published between database inception and December 8, 2022.

Study Selection

This systematic review and meta-analysis included randomized clinical trials, cohort studies, and cross-sectional studies reporting perinatal outcomes following induction of labor at 39 weeks vs expectant management.

Data Extraction and Synthesis

Two reviewers independently assessed study eligibility, extracted data, and assessed studies for bias. Pooled odds ratios (ORs) and 95% CIs were calculated using a random-effects model. This study is reported per the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 guideline, and the protocol was prospectively registered with PROSPERO.

Main Outcomes and Measures

Maternal outcomes of interest included emergency cesarean section, perineal injury, postpartum hemorrhage, and operative vaginal birth. Neonatal outcomes of interest included admission to the neonatal intensive care unit, low 5-minute Apgar score (<7) after birth, macrosomia, and shoulder dystocia.

Results

Of the 5827 records identified in the search, 14 studies were eligible for inclusion in this review. These studies reported outcomes for 1 625 899 women birthing a singleton pregnancy. Induction of labor at 39 weeks of gestation was associated with a 37% reduced likelihood of third- or fourth-degree perineal injury (OR, 0.63 [95% CI, 0.49-0.81]), in addition to reductions in operative vaginal birth (OR, 0.87 [95% CI, 0.79-0.97]), macrosomia (OR, 0.66 [95% CI, 0.48-0.91]), and low 5-minute Apgar score (OR, 0.62 [95% CI, 0.40-0.96]). Results were similar when confined to multiparous women only, with the addition of a substantial reduction in the likelihood of emergency cesarean section (OR, 0.61 [95% CI, 0.38-0.98]) and no difference in operative vaginal birth (OR, 1.01 [95% CI, 0.84-1.21]). However, among nulliparous women only, induction of labor was associated with an increased likelihood of shoulder dystocia (OR, 1.22 [95% CI, 1.02-1.46]) compared with expectant management.

Conclusions and Relevance

In this study, induction of labor at 39 weeks was associated with improved maternal labor-related and neonatal outcomes. However, among nulliparous women, induction of labor was associated with shoulder dystocia. These results suggest that elective induction of labor at 39 weeks may be safe and beneficial for some women; however, potential risks should be discussed with nulliparous women.

Does induction of labor at 41 weeks (early, mid or late) improve birth outcomes in low-risk pregnancy? A nationwide propensity score-matched study

INTRODUCTION

This study aimed to assess whether induction of labor at 41 weeks of gestation improved perinatal outcomes in a low-risk pregnancy compared with expectant management.

MATERIAL AND METHODS

Registry-based national cohort study in The Netherlands. The study population comprised 239 971 low-risk singleton pregnancies from 2010 to 2019, with birth occurring from 41+0 to 42+0 weeks. We used propensity score matching to compare induction of labor in three 2-day groups to expectant management, and further conducted separate analyses by parity. The main outcome measures were stillbirth, perinatal mortality, 5-min Apgar <4 and <7, neonatal intensive care unit (NICU) admissions ≥24 h, and emergency cesarean section rate.

RESULTS

Compared with expectant management, induction of labor at 41+0 to 41+1 weeks resulted in reduced stillbirths (adjusted odds ratio [aOR] 0.15, 95% confidence interval [CI] 0.05-0.51) in both nulliparous and multiparous women. Induction of labor increased 5-min Apgar score <7 (aOR 1.30, 95% CI 1.09-1.55) and NICU admissions ≥24 h (aOR 2.12, 95% CI 1.53-2.92), particularly in nulliparous women, and increased the cesarean section rate (aOR 1.42, 95% CI 1.34-1.51). At 41+2-41+3 weeks, induction of labor reduced perinatal mortality (aOR 0.13, 95% CI 0.04-0.43) in both nulliparous and multiparous women. The rate of 5-min Apgar score <7 was increased (aOR 1.26, 95% CI 1.06-1.50), reaching significance in multiparous women. The cesarean section rate increased (aOR 1.57, 95% CI 1.48-1.67) in both nulliparous and multiparous women. Induction of labor at 41+4 to 41+5 weeks reduced stillbirths (aOR 0.30, 95% CI 0.10-0.93). Induction of labor increased rates of 5-min Apgar score <4 (aOR 1.61, 95% CI 1.01-2.56) and NICU admissions ≥24 h (aOR 1.52, 95% CI 1.08-2.13) in nulliparous women. Cesarean section rate was increased (aOR 1.47, 95% CI 1.38-1.57) in nulliparous and multiparous women.

CONCLUSIONS

At 41+2 to 41+3 weeks, induction of labor reduced perinatal mortality, and in all 2-day groups at 41 weeks, it reduced stillbirths, compared with expectant management. Low 5-min Apgar score (<7 and <4) and NICU admissions ≥24 h occurred more often with induction of labor, especially in nulliparous women. Induction of labor in all 2-day groups coincided with elevated cesarean section rates in nulliparous and multiparous women. These findings pertaining to the choice of induction of labor versus expectant management should be discussed when counseling women at 41 weeks of gestation.

Cost-effectiveness analysis of induction of labour at 41 weeks and expectant management until 42 weeks in low risk women (INDEX trial)

Objective

To assess the cost-effectiveness of elective induction of labour (IOL) at 41 weeks and expectant management (EM) until 42 weeks.

Design

Cost-effectiveness analysis from a healthcare perspective alongside a randomised controlled trial (INDEX).

Setting

123 primary care midwifery practices and 45 obstetric departments of hospitals in the Netherlands.

Population

We studied 1801 low-risk women with late-term pregnancy, randomised to IOL at 41 weeks (N = 900) or EM until 42 weeks (N = 901).

Methods

The incremental cost-effectiveness ratio (ICER) was expressed as the ratio of the difference in costs and the difference in main perinatal outcomes. A Cost-Effectiveness Acceptability Curve (CEAC) was constructed to assess whether induction is cost-effective for a range of monetary values as thresholds. We performed subgroup analysis for parity.

Main outcome measures

Direct medical costs, composite adverse perinatal outcome (CAPO) (perinatal mortality, NICU admission, Apgar 5 min < 7, plexus brachialis injury and/or meconium aspiration syndrome) and composite severe adverse perinatal outcome (SAPO) (including Apgar 5 min < 4 instead of < 7).

Results

The average costs were €3858 in the induction group and €3723 in the expectant group (mean difference €135; 95 % CI -235 to 493). The ICERs of IOL compared to EM to prevent one additional CAPO and SAPO was €9436 and €14,994, respectively. The CEAC showed a 80 % chance of IOL being cost-effective with a willingness-to-pay of €22,000 for prevention of one CAPO and €50,000 for one SAPO. Subgroup analysis showed a willingness-to-pay to prevent one CAPO for nulliparous of €47,000 and for multiparous €190,000. To prevent one SAPO the willingness-to-pay is €62,000 for nulliparous and €970,000 for multiparous women.

Conclusions

Induction at 41 weeks has an 80 % chance of being cost-effective at a willingness-to-pay of €22,000 for prevention of one CAPO and €50,000 for prevention of one SAPO. Subgroup analysis suggests that induction could be cost-effective for nulliparous women while it is unlikely cost-effective for multiparous women.Cost-effectiveness in other settings will depend on baseline characteristics of the population and health system organisation and funding.

Women’s lived experiences of induction of labour in late- and post-term pregnancy within the Swedish post-term induction study – a phenomenological study

Purpose

There is a trend worldwide to induce pregnant women earlier. However, few studies have focused on women’s experiences. The aim was to gain a deeper understanding of women’s lived experiences of induction of labour in late- and post-term pregnancy.

Methods

Phenomenology with a reflective lifeworld approach was chosen as the method. Twelve women participating in a larger study in which women were randomized to either induction of labour in week 41 or to expectant management until week 42, were interviewed one to three months after giving birth.

Results

The essence is described as follows: labour becomes another journey than the intended one. The women adapted to this new journey by seeing the advantages and handing themselves over to the healthcare system, but at the same time something about giving birth could be lost. The result is further described by its four constituents: planning the unplannable, being a guest at the labour ward, someone else controlling the labour, and overshadowed by how it turned out.

Conclusion

Induced labour presents a challenge to maternity personnel to support the birthing woman’s normal progress, not to rush her through labour, and to involve her in the process.

Maternal and Neonatal Outcomes of Elective Induction of Labor at 39 or More Weeks: A Prospective, Observational Study

The purpose of our study is to compare the maternal and neonatal outcomes of induction of labor (IOL) versus expectant management at 39 weeks of gestation. We conducted a single-centered, prospective, observational study of nulliparous singleton women at 39 weeks or more. We compared the maternal and perinatal outcomes. Of 408 nulliparous women, 132 women were IOL group and 276 women were expectant management group. IOL and expectant group had similar cesarean delivery rate (18.2% vs. 15.9%, p = 0.570). The delivery time from admission was longer in IOL group (834 ± 527 vs. 717 ± 469 min, p = 0.040). The IOL group was less likely to have Apgar score at 5 min < 7 than in expectant group (0.8% vs. 5.4%, p = 0.023). Multivariate analysis showed that IOL at 39 weeks was not an independent risk factor for cesarean delivery (relative risk 0.64, 95% confidence interval: 0.28−1.45, p = 0.280). Maternal and neonatal adverse outcomes, including cesarean delivery rate, were similar to women in IOL at 39 weeks of gestation compared to expectant management in nulliparous women. IOL at 39 weeks of gestation could be recommended even when the indication of IOL is not definite.

Balloon catheters versus vaginal prostaglandins for labour induction (CPI Collaborative): an individual participant data meta-analysis of randomised controlled trials

BACKGROUND

Induction of labour is one of the most common obstetric interventions globally. Balloon catheters and vaginal prostaglandins are widely used to ripen the cervix in labour induction. We aimed to compare the effectiveness and safety profiles of these two induction methods.

METHODS

We did an individual participant data meta-analysis comparing balloon catheters and vaginal prostaglandins for cervical ripening before labour induction. We systematically identified published and unpublished randomised controlled trials that completed data collection between March 19, 2019, and May 1, 2021, by searching the Cochrane Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and PubMed. Further trials done before March 19, 2019, were identified through a recent Cochrane review. Data relating to the combined use of the two methods were not included, only data from women with a viable, singleton pregnancy were analysed, and no exclusion was made based on parity or membrane status. We contacted authors of individuals trials and participant-level data were harmonised and recoded according to predefined definitions of variables. Risk of bias was assessed with the ROB2 tool. The primary outcomes were caesarean delivery, indication for caesarean delivery, a composite adverse perinatal outcome, and a composite adverse maternal outcome. We followed the intention-to-treat principle for the main analysis. The primary meta-analysis used two-stage random-effects models and the sensitivity analysis used one-stage mixed models. All models were adjusted for maternal age and parity. This meta-analysis is registered with PROSPERO (CRD42020179924).

FINDINGS

Individual participant data were available from 12 studies with a total of 5460 participants. Balloon catheters, compared with vaginal prostaglandins, did not lead to a significantly different rate of caesarean delivery (12 trials, 5414 women; crude incidence 27·0%; adjusted OR [aOR] 1·09, 95% CI 0·95-1·24; I²=0%), caesarean delivery for failure to progress (11 trials, 4601 women; aOR 1·20, 95% CI 0·91-1·58; I²=39%), or caesarean delivery for fetal distress (10 trials, 4441 women; aOR 0·86, 95% CI 0·71-1·04; I²=0%). The composite adverse perinatal outcome was lower in women who were allocated to balloon catheters than in those allocated to vaginal prostaglandins (ten trials, 4452 neonates, crude incidence 13·6%; aOR 0·80, 95% CI 0·70-0·92; I²=0%). There was no significant difference in the composite adverse maternal outcome (ten trials, 4326 women, crude incidence 22·7%; aOR 1·02, 95% CI 0·89-1·18; I²=0%).

INTERPRETATION

In induction of labour, balloon catheters and vaginal prostaglandins have comparable caesarean delivery rates and maternal safety profiles, but balloon catheters lead to fewer adverse perinatal events.

FUNDING

Australian National Health and Medical Research Council and Monash Health Emerging Researcher Fellowship.

Perinatal mortality and neonatal and maternal outcome per gestational week in term pregnancies: A registry-based study

INTRODUCTION

Human pregnancy is considered term from 37+0/7 to 41+6/7 weeks. Within this range, both maternal, fetal and neonatal risks may vary considerably. This study investigates how gestational age per week is related to the components of perinatal mortality and parameters of adverse neonatal and maternal outcome at term.

MATERIAL AND METHODS

A registry-based study was made of all singleton term pregnancies in the Netherlands from January 2014 to December 2017. Stillbirth and early neonatal mortality, as components of perinatal mortality, were defined as primary outcomes; adverse neonatal and maternal events as secondary outcomes. Neonatal adverse outcomes included birth trauma, 5-minute Apgar score ≤3, asphyxia, respiratory insufficiency, neonatal intensive care unit admission and composite neonatal outcome. Maternal adverse outcomes included instrumental vaginal birth, emergency cesarean section, obstetric anal sphincter injury, postpartum hemorrhage, hypertensive disorders of pregnancy and composite maternal outcome. The primary outcomes were evaluated by comparing weekly prospective risks of stillbirth and neonatal death using a fetuses-at-risk approach. Secondly, odds ratios (OR) for perinatal mortality, adverse neonatal and maternal outcome using a births-based approach were compared for each gestational week with all births occurring after that week.

RESULTS

Data of 581 443 births were analyzed. At 37, 38, 39, 40, 41 and 42 weeks, the respective weekly prospective risks of stillbirth were 0.015%, 0.022%, 0.031%, 0.036%, 0.069% and 0.081%; the respective weekly prospective risks of early neonatal death were 0.051%, 0.047%, 0.032%, 0.031%, 0.039% and 0.035%. The OR for adverse neonatal outcomes were the lowest at 39 and 40 weeks. The OR for adverse maternal outcomes, including operative birth, continuously increased with each gestational week.

CONCLUSIONS

The prospective risk of early neonatal death for babies born at 39 weeks is lower than the risk of stillbirth in pregnancies continuing beyond 39+6/7 weeks. Birth at 39 weeks was associated with the best combined neonatal and maternal outcome, fewer operative births and fewer maternal and neonatal adverse outcomes compared with pregnancies continuing beyond 39 weeks. This information with appropriate perspectives should be included when counseling term pregnant women.

Elective induction of labour and expectant management in late-term pregnancy: A prospective cohort study alongside the INDEX randomised controlled trial

Objective

To assess adverse perinatal outcomes and caesarean section of low-risk women receiving elective induction of labour at 41 weeks or expectant management until 42 weeks according to their preferred and actual management strategy.

Design

Multicentre prospective cohort study alongside RCT.

Setting

90 midwifery practices and 12 hospitals in the Netherlands.

Population

3642 low-risk women with uncomplicated singleton late-term pregnancy.

Main outcome measures

Composite adverse outcome (perinatal death, Apgar score 5′ < 7, NICU admission, meconium aspiration syndrome), composite severe adverse perinatal outcome (all above with Apgar score 5′ < 4 instead of < 7) and caesarean section.

Results

From 2012–2016, 3642 women out of 6088 eligible women for the INDEX RCT, participated in the cohort study for observational data collection (induction of labour n = 372; expectant management n = 2174; unknown preference/management strategy n = 1096).

Adverse perinatal outcome occurred in 1.1 % (4/372) in the induction group versus 1.9 % (42/2174) in the expectant group (adjRR 0.56; 95 %CI: 0.17–1.79), with severe adverse perinatal outcome occurring in 0.3 % (1/372) versus 1.0 % (22/2174), respectively (adjRR 0.39; 95 % CI: 0.05–2.88). There were no stillbirths among all 3642 women; one neonatal death occurred in the unknown preference/management group. Caesarean section rates were 10.5 % (39/372) after induction and 8.9 % (193/2174) after expectant management (adjRR 1.32; 95 % CI: 0.95–1.84).

A higher incidence of adverse perinatal outcome was observed in nulliparous compared to multiparous women. Nulliparous 1.8 % (3/170) in the induction group versus 2.6 % (30/1134) in the expectant management group (adjRR 0.58; 95 % CI 0.14–2.41), multiparous 0.5 % (1/201) versus 1.1 % (11/1039) (adjRR 0.54; 95 % CI 0.07–24.19). One maternal death due to amniotic fluid embolism occurred after elective induction at 41 weeks + 6 days.

Conclusion

In this cohort study among low-risk women receiving the policy of their preference in late-term pregnancy, a non-significant difference was found between induction of labour at 41 weeks and expectant management until 42 weeks in absolute risks of composite adverse (1.1 % versus 1.9 %) and severe adverse (0.3 % versus 1.0 %) perinatal outcome. The risks in this cohort study were lower than in the trial setting. There were no stillbirths among all 3642 women. Caesarean section rates were comparable.

•

No stillbirths in late-term pregnancy (IOL or EM) of 3642 women in INDEX-cohort.

•

Less adverse perinatal outcomes in INDEX-cohort than in trial with comparable risk difference.

•

More women approaching late-term pregnancy prefer EM, not elective induction.

Relation between perinatal outcome and gestational duration in term primiparous pregnancies stratified by body mass index

INTRODUCTION

There is growing evidence that induction of labor at 41 completed weeks improves neonatal outcome, at least among primiparous women. This study was performed to investigate whether maternal body mass index (BMI) should be considered when deciding on timing of intervention in term pregnancies.

MATERIAL AND METHODS

The study design was a historical cohort study using data from the Swedish Medical Birth Register, singletons in cephalic presentation with births 39+0 to 41+6 weeks, with available information on maternal BMI 2005-2017 (n = 352 567). Modified Poisson regression analyses were used to investigate the association between gestational duration and stillbirth or death before 45 postmenstrual weeks (primary outcome) and Apgar score <7 at 5 minutes (secondary outcome) by BMI, respectively. Adjustments were made for maternal age, smoking, country of birth and educational level.

RESULTS

The adjusted relative risk (ARR) of stillbirth or death before 45 weeks among infants born at 41+0 to 41+6 vs 40+0 to 40+6 weeks, was 1.26 with a 95% confidence interval (CI) of 1.07-1.48. Among women with BMI ≥30, the offspring mortality risk in pregnancies lasting 39+0 to 39+2 weeks was significantly above the corresponding risk among women of normal BMI who delivered at 41+0 to 41+2 weeks (ARR = 1.95; 95% CI 1.07-3.56) but no statistically significant heterogeneity was found regarding the magnitude of the association between gestational duration and offspring mortality. The ARR, for Apgar <7 at 5 minutes (41+0 to 41+6 vs 40+0 to 40+6 weeks, regardless of BMI), was 1.36 (95% CI 1.27-1.45). The risk for low Apgar score at 41+0 weeks was 1.5% among all children regardless of maternal BMI. Among children to women with BMI ≥30, this magnitude of risk was found already at 39+3 weeks.

CONCLUSIONS

In primiparous women with obesity the risk of stillbirth or death before 45 postmenstrual weeks were increased throughout all full-term gestational age categories, compared with women with overweight or normal BMI. Children to obese women had the same risk for Apgar scores <7 at 5 minutes compared with women overall at earlier gestational age. The results suggest that maternal BMI needs to be considered when discussing timing of elective induction in term healthy pregnancies of primiparous women.

Microbial and human transcriptome in vaginal fluid at midgestation: Association with spontaneous preterm delivery

BACKGROUND

Intrauterine infection and inflammation caused by microbial transfer from the vagina are believed to be important factors causing spontaneous preterm delivery (PTD). Multiple studies have examined the relationship between the cervicovaginal microbiome and spontaneous PTD with divergent results. Most studies have applied a DNA-based assessment, providing information on the microbial composition but not transcriptional activity. A transcriptomic approach was applied to investigate differences in the active vaginal microbiome and human transcriptome at midgestation between women delivering spontaneously preterm versus those delivering at term.

METHODS

Vaginal swabs were collected in women with a singleton pregnancy at 18 + 0 to 20 + 6 gestational weeks. For each case of spontaneous PTD (delivery <37 + 0 weeks) two term controls were randomized (39 + 0 to 40 + 6 weeks). Vaginal specimens were subject to sequencing of both human and microbial RNA. Microbial reads were taxonomically classified using Kraken2 and RefSeq as a reference. Statistical analyses were performed using DESeq2. GSEA and HUMAnN3 were used for pathway analyses.

RESULTS

We found 17 human genes to be differentially expressed (false discovery rate, FDR < 0.05) in the preterm group (n = 48) compared to the term group (n = 96). Gene expression of kallikrein-2 (KLK2), KLK3 and four isoforms of metallothioneins 1 (MT1s) was higher in the preterm group (FDR < 0.05). We found 11 individual bacterial species to be differentially expressed (FDR < 0.05), most with a low occurrence. No statistically significant differences in bacterial load, diversity or microbial community state types were found between the groups.

CONCLUSIONS

In our mainly white population, primarily bacterial species of low occurrence were differentially expressed at midgestation in women who delivered preterm versus at term. However, the expression of specific human transcripts including KLK2, KLK3 and several isoforms of MT1s was higher in preterm cases. This is of interest, because these genes may be involved in critical inflammatory pathways associated with spontaneous PTD.

Time of delivery among low-risk women at 37-42 weeks of gestation and risks of stillbirth and infant mortality, and long-term neurological morbidity

BACKGROUND

The most important knowledge gap in connection with obstetric management for time of delivery in term low-risk pregnancies relates to the absence of information on long-term neurodevelopmental outcomes.

OBJECTIVES

We examined risks of stillbirth, infant mortality, cerebral palsy (CP) and epilepsy among low-risk pregnancies.

METHODS

In this population-based Swedish study, we identified, from 1998 to 2019, 1,773,269 singleton infants born between 37 and 42 completed weeks in women with low-risk pregnancies. Poisson log-linear regression models were used to examine the association between gestational age at delivery and stillbirth, infant mortality, CP and epilepsy. Adjusted rate ratios (RR) and 95% confidence intervals expressing the effect of birth at a particular gestational week compared with birth at a later gestational week were estimated.

RESULTS

Compared with those born at a later gestation, RRs for stillbirth and infant mortality were higher among births at 37 weeks' and 38 weeks' gestation. The RRs for infant mortality were approximately 20% and 25% lower among births at 40 or 41 weeks compared with those born at later gestation, respectively. Infants born at 37 and 38 weeks also had higher RRs for CP (vs infants born at ≥38 and ≥39 weeks, respectively), while those born at 39 gestation had similar RRs (vs infants born at ≥40 weeks); infants born at 40 and 41 weeks had lower RRs of CP (vs those born at ≥41 and 42 weeks, respectively). The RRs for epilepsy were higher in those born at 37 and 38 weeks compared with those born at later gestation.

CONCLUSIONS

Among low-risk pregnancies, birth at 37 or 38 completed weeks' gestation is associated with increased risks of stillbirth, infant mortality and neurological morbidity, while birth at 39-40 completed weeks is associated with reduced risks compared with births at later gestation.

Optimal timing of labour induction in contemporary clinical practice

Induction of labour (IoL) is generally conducted when maternal and foetal risks of remaining pregnant outweigh the risks of delivery. With emerging literature around non-medically indicated IoL, contemporary clinical practice has seen an increase in IoL at 39 weeks' gestation. This review highlights recent evidence on the most common indications for IoL including gestational diabetes, hypertensive disorders of pregnancy, intrahepatic cholestasis of pregnancy, and post-term pregnancies. It also summarizes the evidence related to the timing of IoL for other common conditions based on recent literature reviews.

Stillbirth or neonatal death before 45 post-menstrual weeks in relation to gestational duration in pregnancies at 39 weeks of gestation or beyond: the impact of parity and body mass index. A national cohort study

OBJECTIVE

To investigate the risk of stillbirth or neonatal death before 45 post-menstrual weeks in relation to gestational duration, stratified by body mass index (BMI) and parity.

DESIGN

Retrospective study.

SETTING

Data from the Swedish Medical Birth Register.

POPULATION

Singleton, cephalic births at between 39⁺⁰ and 42⁺²  weeks of gestation, 2005-2016 (n = 892 339).

METHODS

Relative risk ratios for mortality in relation to gestational duration were stratified by parity and BMI, and were adjusted for maternal age, smoking, country of birth and educational level.

MAIN OUTCOME MEASURES

Primary outcome: stillbirth or neonatal death before 45 post-menstrual weeks. Secondary outcome: stillbirth.

RESULTS

Among children of primiparous women, children born at 41⁺³  weeks of gestation, or later, were at increased risk of stillbirth or neonatal death before 45 post-menstrual weeks compared with children born between 39⁺⁰ and 40⁺²  weeks of gestation (aRR 1.29, 95% CI 1.10-1.52). For primiparous women with BMIs of <25, 25-29.9 and ≥ 30 kg/m² , the corresponding aRRs were: 1.04 (95% CI 0.81-1.34), 1.25 (95% CI 0.94-1.66) and 1.52 (95% CI 1.10-2.10), respectively. No significant increase in risk with gestational age was detected for multiparous women, regardless of BMI class. Among primipara, the risk of stillbirth increased with gestational duration in all BMI classes, with the highest risk increase for BMI ≥ 30 kg/m² , from 0.8/1000 at 40⁺³ -40⁺⁶  weeks of gestation to 4.0/1000 at 42⁺⁰ -42⁺²  weeks of gestation.

CONCLUSIONS

At 41⁺³ -42⁺²  weeks of gestation, pregnancy duration was associated with an increased risk for stillbirth or neonatal death before 45 post-menstrual weeks among primiparous women, especially among women who were obese. For multiparous women, no significant association between gestational duration and mortality was found.

TWEETABLE ABSTRACT

In term pregnancies the risk for stillbirth and neonatal death is affected by gestational age, parity and BMI.

Induction of labour at 41 weeks of gestation versus expectant management and induction of labour at 42 weeks of gestation: a cost-effectiveness analysis

OBJECTIVE

To assess the cost-effectiveness of induction of labour (IOL) at 41 weeks of gestation compared with expectant management until 42 weeks of gestation.

DESIGN

A cost-effectiveness analysis alongside the Swedish Post-term Induction Study (SWEPIS), a multicentre, randomised controlled superiority trial.

SETTING

Fourteen Swedish hospitals during 2016-2018.

POPULATION

Women with an uncomplicated singleton pregnancy with a fetus in cephalic position were randomised at 41 weeks of gestation to IOL or to expectant management and induction at 42 weeks of gestation.

METHODS

Health benefits were measured in life years and quality-adjusted life years (QALYs) for mother and child. Total cost per birth was calculated, including healthcare costs from randomisation to discharge after delivery, for mother and child. Incremental cost-effectiveness ratios (ICERs) were calculated by dividing the difference in mean cost between the trial arms by the difference in life years and QALYs, respectively. Sampling uncertainty was evaluated using non-parametric bootstrapping.

MAIN OUTCOME MEASURES

The cost per gained life year and per gained QALY.

RESULTS

The differences in life years and QALYs gained were driven by the difference in perinatal mortality alone. The absolute risk reduction in mortality was 0.004 (from 6/1373 to 0/1373). Based on Swedish life tables, this gives a mean gain in discounted life years and QALYs of 0.14 and 0.12 per birth, respectively. The mean cost per birth was €4108 in the IOL group (n = 1373) and €4037 in the expectant management group (n = 1373), with a mean difference of €71 (95% CI -€232 to €379). The ICER for IOL compared with expectant management was €545 per life year gained and €623 per QALY gained. Confidence intervals were relatively wide and included the possibility that IOL had both lower costs and better health outcomes.

CONCLUSIONS

Induction of labour at 41 weeks of gestation results in a better health outcome and no significant difference in costs. IOL is cost-effective compared with expectant management until 42 weeks of gestation using standard threshold values for acceptable cost per life year/QALY.

TWEETABLE ABSTRACT

Induction of labour at 41 weeks of gestation is cost-effective compared with expectant management until 42 weeks of gestation.

FIGO good practice recommendations on modifiable causes of iatrogenic preterm birth

Iatrogenic preterm birth is a planned delivery that occurs before 37 weeks of gestation due to maternal and/or fetal causes. However, in some cases, such deliveries also occur with no apparent medical indication. The increasing numbers of iatrogenic preterm deliveries worldwide have led researchers to identify modifiable causes that allow the formulation of preventive strategies that could impact the overall preterm birth rate. The present document contains the FIGO (International Federation of Gynecology and Obstetrics) Working Group for Preterm Birth recommendations, aiming to reduce the rates of iatrogenic preterm birth based on four of the most common clinical scenarios and issues related to iatrogenic preterm delivery. The working group supports efforts to identify the contribution of iatrogenic preterm delivery to the overall preterm birth rate and encourages health authorities to establish preventive measures accordingly. We encourage care providers to maintain single embryo transfer policies to prevent multiple pregnancies as a substantial contributor of iatrogenic preterm birth. The working group also recommends that efforts to reduce unnecessary cesarean sections must be warranted, and mechanisms to ensure the appropriate time of delivery and strengthening of education and communication processes must be pursued.

Iatrogenic preterm birth contributes substantially to preterm birth rates globally and can be mitigated by identifying modifiable factors and formulating and supporting preventive strategies.

Induction of labour in low-resource settings

Due to the disparity in resource availability between low- and high-resource settings, practice recommendations relevant to high-income countries are not always relevant and often need to be adapted to low-resource settings. The adaptation applies to induction of labour (IOL) which is an obstetric procedure that deserves special attention because it involves the initiation of a process that requires regular and frequent monitoring of the mother and foetus by experienced healthcare professionals. Lack of problem recognition and/or substandard care during IOL may result in harm with long-term sequelae. In this article, the authors discuss unique challenges such as insufficient resources (including staff, midwives, doctors, equipment, and medications) that result in occasional inadequate patient monitoring and/or delayed interventions during IOL in low-resource settings. We also discuss modifications in indications and methods for IOL, issues related to human immunodeficiency virus (HIV) infections, the feasibility of outpatient induction, clinical protocols and a minimum dataset for quality improvement projects. Overall, the desire to achieve a vaginal birth with IOL should not cloud the necessity to observe the required safety measures and implement necessary interventions; given that childbirth practices are the major determinants of pregnancy outcomes and patient satisfaction.

Efficacy and safety of oral misoprostol vs transvaginal balloon catheter for labor induction: An observational study within the SWEdish Postterm Induction Study (SWEPIS)

INTRODUCTION

Induction of labor is increasing. A common indication for induction of labor is late term and postterm pregnancy at 41 weeks or more. We aimed to evaluate if there are any differences regarding efficacy, safety, and women's childbirth experience between oral misoprostol and transvaginal balloon catheter for cervical ripening in women with a low-risk singleton pregnancy and induction of labor at 41⁺⁰ to 42^{+0 to 1} weeks of gestation.

MATERIAL AND METHODS

In this observational study, based on data from the Swedish Postterm Induction Study (SWEPIS), a multicenter randomized controlled trial, a total of 1213 women with a low-risk singleton pregnancy at 41 to 42 weeks of gestation were induced with oral misoprostol (n = 744) or transvaginal balloon catheter (n = 469) at 15 Swedish delivery hospitals. The primary efficacy outcome was vaginal delivery within 24 h and primary safety outcomes were neonatal and maternal composite adverse outcomes. Secondary outcomes included time to vaginal delivery and mode of delivery. Women's childbirth experience was assessed with the Childbirth Experience Questionnaire (CEQ 2.0) and visual analog scale. We present crude and adjusted mean differences and relative risks (RR) with 95% CI. Adjustment was performed for a propensity score based on delivery hospital and baseline characteristics including Bishop score.

RESULTS

Vaginal delivery within 24 h was significantly lower in the misoprostol group compared with the balloon catheter group (46.5% [346/744] vs 62.7% [294/469]; adjusted RR 0.76 95% CI 0.640.89]). Primary neonatal and maternal safety outcomes did not differ between groups (neonatal composite 3.5% [36/744] vs 3.2% [15/469]; adjusted RR 0.77 [95% CI 0.31-1.89]; maternal composite 2.3% [17/744] vs 1.9% [9/469]; adjusted RR 1.70 [95% CI 0.58-4.97]). Adjusted mean time to vaginal delivery was increased by 3.8 h (95% CI 1.3-6.2 h) in the misoprostol group. Non-operative vaginal delivery and cesarean delivery rates did not differ. Women's childbirth experience was positive overall and similar in both groups.

CONCLUSIONS

Induction of labor with oral misoprostol compared with a transvaginal balloon catheter was associated with a lower probability of vaginal delivery within 24 h and a longer time to vaginal delivery. However, primary safety outcomes, non-operative vaginal delivery, and women's childbirth experience were similar in both groups. Therefore, both methods can be recommended in women with low-risk postdate pregnancies.

Women's childbirth experiences in the Swedish Post-term Induction Study (SWEPIS): a multicentre, randomised, controlled trial

OBJECTIVE

To compare childbirth experiences in women randomly assigned to either induction of labour at 41 weeks or to expectant management until 42 weeks, in the Swedish Post-term Induction Study.

DESIGN

A register-based, multicentre, randomised, controlled, superiority trial.

SETTING

Women were recruited at 14 hospitals in Sweden, 2016-2018.

PARTICIPANTS

Women with an uncomplicated singleton pregnancy were recruited at 41 gestational weeks.

INTERVENTIONS

The women were randomly assigned to induction of labour at 41 weeks (induction group, n=1381) or expectant management until 42 weeks (expectant management group, n=1379).

OUTCOME MEASURES

As main outcome, women's childbirth experiences were measured using the Childbirth Experience Questionnaire version 2 (CEQ2), in 656 women, 3 months after the birth at three hospitals. As exploratory outcome, overall childbirth experience was measured in 1457 women using a Visual Analogue Scale (VAS 1-10) within 3 days after delivery at the remaining eleven hospitals.

RESULTS

The total response rate was 77% (2113/2760). There were no significant differences in childbirth experience measured with CEQ2 between the groups (induction group, n=354; expectant management group, n=302) in the subscales: own capacity (2.8 vs 2.7, p=0.09), perceived safety (3.3 vs 3.2, p=0.06) and professional support (3.6 vs 3.5, p=0.38) or in the total CEQ2 score (3.3 vs 3.2, p=0.07), respectively. Women in the induction group scored higher in the subscale participation (3.6 vs 3.4, p=0.02), although with a small effect size (0.19). No significant difference was observed in overall childbirth experience according to VAS (8.0 (n=735) vs 8.1 (n=735), p=0.22).

CONCLUSIONS

There were no differences in childbirth experience, according to CEQ2 or overall childbirth experience assessed with VAS, between women randomly assigned to induction of labour at 41 weeks or expectant management until 42 weeks. Overall, women rated their childbirth experiences high.

TRIAL REGISTRATION NUMBER

ISRCTN26113652.