Adverse obstetrical and neonatal outcomes in elective and medically indicated inductions of labor at term

The ARRIVE Trial

Timing of delivery such that maternal and perinatal outcomes are optimized is among the most important and commonplace decisions in obstetric care. Given the importance of this determination, it is somewhat surprising that there has been, until relatively recently, little in the way of high-quality evidence to guide obstetric clinicians in this decision. This chapter describes the evolution of studies examining the effects of labor induction and the importance of the ARRIVE trial in that context.

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.

The infection, cervical and perineal lacerations in relation to postpartum hemorrhage following vaginal delivery induced by Cook balloon catheter

OBJECTIVE

To identify whether infection, cervical laceration and perineal laceration are associated with postpartum hemorrhage in the setting of vaginal delivery induced by Cook balloon catheter.

MATERIALS AND METHODS

The retrospective study included 362 women who gave birth vaginally at or beyond 37 weeks of gestation with a diagnosis of postpartum hemorrhage between February 2021 to May 2022, of which including 216 women with induction of labor (Cook balloon catheter followed by oxytocin or oxytocin) and 146 women with spontaneous delivery. Risk factors for postpartum hemorrhage were collected and compared.

RESULTS

362 women were divided into three groups, group 1 with spontaneous delivery, group 2 with oxytocin, group 3 with Cook balloon catheter followed by oxytocin. There was no significant difference in incidence of infection within three groups (P > 0.05). The rate of cervical laceration and perineal laceration was significantly higher in group 3 compared with groups 2 and 1 (P < 0.05); Multivariate logistic regression analysis found that compared with group 1, either group 3 or group 2 was associated with increased risks of cervical laceration and perineal laceration (P < 0.05), and compared with group 2, group 3 was not associated with increased risks of cervical laceration and perineal laceration (P > 0.05).

CONCLUSION

Infection, cervical laceration and perineal laceration are identified not to be independent risk factors for postpartum hemorrhage for women undergoing labor with Cook balloon catheter; Cervical laceration and perineal laceration increase the risk of postpartum hemorrhage in women with labor induction.

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.

Reducing the cesarean delivery rate

BACKGROUND

The cesarean delivery rate has been rising in recent years, having associated maternal morbidities. Elective induction of labor has also been seen to rise during this same time period.

OBJECTIVE

This current study investigated the difference in the cesarean delivery rate between induction of labor and spontaneous labor among nulliparous, term, singleton, and vertex-presenting women.

STUDY DESIGN

A retrospective cohort in a single institution over a seven-year period was used for this analysis, observing the difference in cesarean delivery rate at different term gestational ages and neonatal morbidity using the 5-minute Apgar score < 5.

RESULTS

A statistically significant difference was found in cesarean delivery rate between those women whose labor was induced and those whose labor began spontaneously, at each term gestational age of labor initiation (P < 0.001). The proportion of indications for induction was described (i.e. elective vs. medically-indicated), and no difference was found for neonatal morbidity between the groups analyzed, using the 5-minute Apgar score as the perinatal outcome measure.

CONCLUSION

A comparison was made between spontaneous and induced labor regarding the resultant cesarean delivery rate, and a significant difference was found favoring spontaneous labor. This should be considered when electing to deliver using an induction methodology for nulliparous women, especially when there are no medical indications for it.

Failed induction of labor and its associated factors in Ethiopia: A systematic review and meta-analysis

Introduction

Failed induction increased maternal morbidity and mortality due to the associated complication which comes with cesarean section such as post partum hemorrhage and sepsis. The reports of previous articles on the proportion and associated factor of failed induction were variable and inconsistent. Therefore, this meta-analysis found out that the pooled proportion of failed induction and its associated factors in Ethiopia.

Methods

Systematic search was done by online databases (Pub Med, Web of Science, Google scholar and HINARI, and Ethiopian universities digital libraries). Unpublished studies that are found in the Ethiopian universities’ digital libraries were used for this systematic review and meta-analysis study. Data were entered into Microsoft Excel and then exported to STATA 11 version statistical software for analysis. Heterogeneity assessed using the I² statistic. The pooled proportion of failed induction and the odds ratio (OR) with a 95% confidence interval was showed using forest plots.

Result

The overall proportion of failed induction was 23.58 % (95% CI: 13.72–33.44). Unfavorable Bishop Score [OR = 4.45, 95CI:2.44,8.12 ] intermediate Bishop Score [OR = 8.87, 95CI:4.62,17.05 ] and being primiparous woman [OR = 3.04, 95CI:1.74,5.53 ] were factors associated with failed induction of labour.

Conclusion

The prevalence of failed induction was high in Ethiopia. Unfavorable Bishop Score, intermediate Bishop Score, and primiparous were significantly associated with failed induction. Proper pelvis assessment for Bishop Score will be considered prior to initiating the induction of labor. Beside to this, the health professionals shall be aware of the relevance of cervical ripening for intermediate and unfavorable Bishop Score for pregnant women's before induction of labor.

Target populations to reduce cesarean rates after induced labor: A national population-based cohort study

INTRODUCTION

Great variations in cesarean rates after induction of labor exist and reasons for these disparities remain unclear. They may be explained by individual characteristics or obstetric practices. Ten-group classification systems have proved their utility to monitor cesarean rates in general population. We aimed to identify groups of women that account for most cesareans after induction of labor using the Nippita reproducible 10-group classification, specifically designed for induced population.

MATERIAL AND METHODS

A prospective population-based cohort study was performed in 94 French maternity units, including 3042 women undergoing induction of labor. Women were sorted according to 10 mutually exclusive groups based on parity, weeks of gestation, number of fetuses, fetal presentation and previous cesarean delivery. Relative size, cesarean delivery rate and contribution to the overall cesarean rate were described for each group. Cesarean rates were compared according to the Bishop score at the onset of labor induction. Indications for cesarean delivery were also described in the groups that contributed most to the overall cesarean rate. The MEDIP protocol was registered in ClinicalTrial (NCT02477085).

RESULTS

The overall cesarean rate was 21.0% among this population of induced women. Nulliparous women with a term singleton cephalic fetus (groups 1, 2 and 3; at 37-38, 39-40 and ≥41 weeks of gestation, respectively) accounted for two-thirds of the overall cesarean rate because they were the largest group (relative size of 10.6, 16.6 and 18.1%, respectively) and had higher cesarean rates (27.2, 30.9 and 33.0%, respectively). When the Bishop score was <6 (n = 2270/3042), cesarean delivery rates were higher (24.1 vs 10.7% if Bishop score ≥6, P < 0.01), in particular for group 1 (29.1 vs 12.5%, P = 0.02), and group 2 (33.3 vs 19.3%, P = 0.01). In groups 1, 2 and 3, which contributed most to the overall cesarean rate, a significant part of the cesareans were performed before 6 cm of cervical dilation for dystocia only (40.0, 16.7 and 17.6%, respectively).

CONCLUSIONS

Nulliparous women with a term singleton cephalic fetus and an unfavorable cervix represent the population to target for auditing induction practices. Specific actions could be implemented among this population to weigh the benefits and risks of induction and improve the management of labor induction.

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.

Elective induction of labor: A prospective observational study

The aim of the present study was to assess indications for induction and describe the characteristics and delivery outcome in medical compared to non-medical/elective inductions. During a three-month period, 1663 term inductions were registered in 24 delivery units in Norway. Inclusion criteria were singleton pregnancies with cephalic presentation at gestational age 37⁺⁰ and beyond. Indications, pre-induction Bishop scores, mode of delivery and adverse maternal and fetal outcomes were registered, and compared between the medically indicated and elective induction groups. Ten percent of the inductions were elective, and the four most common indications were maternal request (35%), a previous negative delivery experience or difficult obstetric history (19%), maternal fatigue/tiredness (17%) and anxiety (15%). Nearly half of these inductions were performed at 39⁺⁰–40⁺⁶ weeks. There were fewer nulliparous women in the elective compared to the medically indicated induction group, 16% vs. 52% (p<0.05). The cesarean section rate in the elective induction group was 14% and 17% in the medically indicated group (14% vs. 17%, OR = 0.8, 95% CI 0.5–1.3). We found that one in ten inductions in Norway is performed without a strict medical indication and 86% of these inductions resulted in vaginal delivery.

Determination of antepartum and intrapartum risk factors associated with neonatal intensive care unit admission

OBJECTIVE

To determine antepartum and intrapartum factors that are associated with admission to neonatal intensive care unit (NICU) among infants delivered between 36.0 and 42.0 weeks at our institution.

METHODS

The retrospective cohort study included 73 consecutive NICU admissions and 375 consecutive non-NICU admissions. Data on demographic, antepartum, intrapartum and neonatal factors were collected. The primary endpoint defined was admission to NICU. Univariate analyses using the Student's t-test, Mann-Whitney U-test, χ2 Fisher's exact test was performed along with multivariate analysis of significant non-redundant variables.

RESULTS

Those with a significantly higher risk of NICU admission underwent induction of labor with prostaglandin analogs (12.5% vs. 24.7%, P=0.007). Length of first stage ≥720 min (33.5% vs. 51.9%, P=0.011), length of second stage of labor ≥240 min (10.6% vs. 31.6%, P<0.001) and prolonged rupture of membranes ≥120 min (54.0% vs. 80.0%, P=0.001) were all associated with an increased chance of NICU admission. Intrapartum factors predictive of NICU admission included administration of meperidine (11.7% vs. 27.4%, P<0.001), presence of preeclampsia (5.5% vs. 0.8%, P=0.015), use of intrapartum IV antihypertensives (1.1% vs. 13.7%, P<0.001), maternal fever (5.3% vs. 31.5%, P<0.001), fetal tachycardia (1.9% vs. 12.3%, P<0.001), and presence of meconium (30% vs. 8%, P<0.001).

CONCLUSION

Identification of modifiable risk factors may reduce neonatal morbidity and mortality. Results from this study can be used to develop and validate a risk model based on combined antepartum and intrapartum risk factors.

Induced Labor in Sweden, 1999-2012: A Population-Based Cohort Study

BACKGROUND

Previous studies show contradictory results about the impact of induced labor on the cesarean delivery rate and few studies have investigated the risk of vacuum extraction subsequent to induced labor. The aims of the present study were to describe the rate of induced labor in Sweden from 1999 to 2012, and to assess the risk of unplanned cesarean delivery and vacuum extraction after induced labor in relation to medical complications and length of gestation.

METHODS

A register-based cohort study was conducted, including 1,078,536 women with spontaneous or induced onset of labor who gave birth by noninstrumental vaginal delivery, unplanned cesarean delivery, or vacuum extraction in gestational week 37 + 0 to 41 + 6. Logistic regression was used to study the association between induced labor and instrumental delivery.

RESULTS

The rate of induced labor increased from 7.7 to 12.9 percent among primiparous and from 7.5 to 11.8 percent among multiparous women. Induced labor was associated with 2-3 times greater risk of unplanned cesarean delivery among all women, except multiparas in gestational week 37-38, and with a 20-50 percent higher risk of vacuum extraction after the adjustment for confounding factors. Among women without a recognized medical complication, induced labor was associated with a threefold increased risk of cesarean delivery in gestational week 39-41 and a 40 percent increase in gestational week 37-38 compared with women with spontaneous onset of labor.

CONCLUSIONS

The proportion of induced labors increased substantially during the 14-year study period and was associated with an increased risk of both cesarean delivery and vacuum extraction, even in women without a documented medical complication. The increased risk of instrumental delivery should be taken into account when counseling about the risks and benefits of induced labor.

Caesarean section rates and adverse neonatal outcomes after induction of labour versus expectant management in women with an unripe cervix: a secondary analysis of the HYPITAT and DIGITAT trials

OBJECTIVE

To evaluate caesarean section and adverse neonatal outcome rates after induction of labour or expectant management in women with an unripe cervix at or near term.

DESIGN

Secondary analysis of data from two randomised clinical trials.

SETTING

Data were collected in two nationwide Dutch trials.

POPULATION

Women with hypertensive disease (HYPITAT trial) or suspected fetal growth restriction (DIGITAT trial) and a Bishop score ≤6.

METHODS

Comparison of outcomes after induction of labour and expectant management.

MAIN OUTCOME MEASURES

Rates of caesarean section and adverse neonatal outcome, defined as 5-minute Apgar score ≤6 and/or arterial umbilical cord pH <7.05 and/or neonatal intensive care unit admission and/or seizures and/or perinatal death.

RESULTS

Of 1172 included women with an unripe cervix, 572 had induction of labour and 600 had expectant management. We found no significant difference in the overall caesarean rate (difference -1.1%, 95% CI -5.4 to 3.2). Induction of labour did not increase caesarean rates in women with Bishop scores from 3 to 6 (difference -2.7%, 95% CI -7.6 to 2.2) or adverse neonatal outcome rates (difference -1.5%, 95% CI -4.3 to 1.3). However, there was a significant difference in the rates of arterial umbilical cord pH <7.05 favouring induction (difference -3.2%, 95% CI -5.6 to -0.9). The number needed to treat to prevent one case of umbilical arterial pH <7.05 was 32.

CONCLUSIONS

We found no evidence that induction of labour increases the caesarean rate or compromises neonatal outcome as compared with expectant management. Concerns over increased risk of failed induction in women with a Bishop score from 3 to 6 seem unwarranted.

TWEETABLE ABSTRACT

Induction of labour at low Bishop scores does not increase caesarean section rate or poor neonatal outcome.

Effects of induction of labour versus expectant management in women with impending post-term pregnancies: the 41 week - 42 week dilemma

BACKGROUND

Post-term pregnancy, a pregnancy exceeding 294 days or 42 completed weeks, is associated with increased perinatal morbidity and mortality and is considered a high-risk condition which requires specialist surveillance and induction of labour. However, there is uncertainty on the policy concerning the timing of induction for post-term pregnancy or impending post-term pregnancy, leading to practice variation between caregivers. Previous studies on induction at or beyond 41 weeks versus expectant management showed different results on perinatal outcome though conclusions in meta-analyses show a preference for induction at 41 weeks. However, interpretation of the results is hampered by the limited sample size of most trials and the heterogeneity in design. Most control groups had a policy of awaiting spontaneous onset of labour that went far beyond 42 weeks, which does not reflect usual care in The Netherlands where induction of labour at 42 weeks is the regular policy. Thus leaving the question unanswered if induction at 41 weeks results in better perinatal outcomes than expectant management until 42 weeks.

METHODS/DESIGN

In this study we compare a policy of labour induction at 41 + 0/+1 weeks with a policy of expectant management until 42 weeks in obstetrical low risk women without contra-indications for expectant management until 42 weeks and a singleton pregnancy in cephalic position. We will perform a multicenter randomised controlled clinical trial. Our primary outcome will be a composite outcome of perinatal mortality and neonatal morbidity. Secondary outcomes will be maternal outcomes as mode of delivery (operative vaginal delivery and Caesarean section), need for analgesia and postpartum haemorrhage (≥1000 ml). Maternal preferences, satisfaction, wellbeing, pain and anxiety will be assessed alongside the trial.

DISCUSSION

This study will provide evidence for the management of pregnant women reaching a gestational age of 41 weeks.

TRIAL REGISTRATION

Dutch Trial Register (Nederlands Trial Register): NTR3431. Registered: 14 May 2012.

Healthy birth practice #1: let labor begin on its own

As cesarean rates have climbed to almost one-third of all births in the United States, current research and professional organizations have identified letting labor begin on its own as one of the most important strategies for reducing the primary cesarean rate. At least equally important, letting labor begin on its own supports normal physiology, prevents iatrogenic prematurity, and prevents the cascade of interventions caused by labor induction. This article is an updated evidence-based review of the "Lamaze International Care Practices That Promote Normal Birth, Care Practice #1: Let Labor Begin on Its Own," published in The Journal of Perinatal Education, 16(3), 2007.