Elective induction of labor: A prospective observational study

Sleep disturbances in late pregnancy: associations with induction of labor

PURPOSE

Sleep disturbances, which are common during pregnancy, may compromise labor. Nevertheless, little is known about associations between sleep disturbances and the likelihood of ending up induction of labor (IOL). Accordingly, we aimed to evaluate the connections between sleep disturbances during pregnancy and IOL.

METHODS

Altogether 1778 women from the FinnBrain Birth Cohort Study with gestation weeks over 37 + 6 were enrolled in the study. The women were divided into IOL (n = 331) and spontaneous onset of labor (SOL, n = 1447) groups. Sleep disturbances in late pregnancy were evaluated using the Basic Nordic Sleep Questionnaire. Logistic regression analyses were conducted with adjustments for age, body mass index, parity, smoking, and depressive symptoms.

RESULTS

Sleep disturbances were frequent in both IOL and SOL groups. In the IOL group 43.0% and in the SOL group 39.0% had poor general sleep quality (P = 0.186). Nocturnal awakenings occurred most commonly, in 94.0% and 93.9%, respectively (P = 0.653). In the IOL group, more women (22.7%) were habitual snorers than in the SOL group (17.0%, P = 0.017), however, the difference lost the statistical significance in adjusted analysis (P = 0.848). Women in the IOL group were more likely to be short sleepers (< 7 h) compared to those in the SOL group (20.2% and 15.4%, respectively, P = 0.034) with no difference after adjustment (P = 0.133). The two groups showed no differences in sleep loss (P = 0.252).

CONCLUSIONS

Deterioration in sleep quality was noticeable in pregnant women, but it was unconnected with IOL. As the frequency of IOL is increasing, more research for related risk factors is needed.

Oxytocin-induced birth causes sex-specific behavioral and brain connectivity changes in developing rat offspring

Despite six decades of the use of exogenous oxytocin for management of labor, little is known about its effects on the developing brain. Motivated by controversial reports suggesting a link between oxytocin use during labor and autism spectrum disorders (ASDs), we employed our recently validated rat model for labor induction with oxytocin to address this important concern. Using a combination of molecular biological, behavioral, and neuroimaging assays, we show that induced birth with oxytocin leads to sex-specific disruption of oxytocinergic signaling in the developing brain, decreased communicative ability of pups, reduced empathy-like behaviors especially in male offspring, and widespread sex-dependent changes in functional cortical connectivity. Contrary to our hypothesis, social behavior, typically impaired in ASDs, was largely preserved. Collectively, our foundational studies provide nuanced insights into the neurodevelopmental impact of birth induction with oxytocin and set the stage for mechanistic investigations in animal models and prospective longitudinal clinical studies.

Comparison of adverse maternal and perinatal outcomes between induction and expectant management among women with gestational diabetes mellitus at term pregnancy: a systematic review and meta-analysis

BACKGROUND

Induction at 38-40 weeks of gestation has been broadly suggested for women with gestational diabetes mellitus (GDM), yet its benefits and risks remain unclear. This study aimed to systematically review and meta-analyze existing evidence on the effect of induction at term gestation among women with GDM.

METHODS

We searched MEDLINE, EMBASE, Cochrane Libraries, and Web of Science from inception to June 2021. We included randomized controlled trials (RCTs) and observational studies comparing induction with expectant management among GDM term pregnancies. Primary outcomes included caesarean section (CS) and macrosomia. All screening and extraction were conducted independently and in duplicates. Meta-analyses with random-effects models were conducted to generate the pooled odds ratios (ORs) and 95% confidence intervals (CIs) using the Mantel-Haenszel method. Methodological quality was assessed independently by two reviewers using the Cochrane Risk of Bias Tool for RCTs and the Newcastle-Ottawa Scale for observational studies.

RESULTS

Of the 4,791 citations, 11 studies were included (3 RCTs and 8 observational studies). Compared to expectant management, GDM women with induction had a significantly lower odds for macrosomia (RCTs 0.49 [0.30-0.81]); observational studies 0.64 [0.54-0.77]), but not for CS (RCTs 0.95 [0.64-1.43]); observational studies 1.03 [0.79-1.34]). Induction was associated with a lower odds of severe perineal lacerations in observational studies (0.59 [0.39-0.88]). No significant difference was observed for other maternal or neonatal morbidities, or perinatal mortality between groups.

CONCLUSIONS

For GDM women, induction may reduce the risk of macrosomia and severe perineal lacerations compared to expectant management. Further rigorous studies with large sample sizes are warranted to better inform clinical implications.

Offspring school performance at age 12 after induction of labor vs non-intervention at term: A linked cohort study

INTRODUCTION

The incidence of induction of labor, for both medical reasons and as an elective procedure, has been rising and a further increase in induction of labor following the ARRIVE trial may be expected. The effects of induction of labor at term on childhood neurodevelopment, however, are not well studied. We aimed to study the influence of elective induction of labor for each week of gestation separately from 37 to 42 weeks on offspring school performance at 12 years of age after uncomplicated pregnancies.

MATERIAL AND METHODS

We performed a population-based study among 226 684 liveborn children from uncomplicated singleton pregnancies, born from 37⁺⁰ to 42⁺⁰  weeks of gestation in cephalic presentation in 2003-2008 (no hypertensive disorders, diabetes or birthweight ≤p5) in the Netherlands. Children with congenital anomalies, of non-white mothers and born after planned cesarean section were excluded. Birth records were linked with national data on school achievement. We compared, using a fetus-at-risk approach and per week of gestation, school performance score and secondary school level at age 12 in those born after induction of labor to those born after non-intervention, ie spontaneous onset of labor in the same week plus all those born at later gestations. Education scores were standardized to a mean of 0 and a standard deviation of 1 and adjusted in the regression analyses.

RESULTS

For each gestational age up to 41 weeks, induction of labor was associated with decreased school performance scores compared with non-intervention (at 37 weeks -0.05 SD, 95% confidence interval [CI] -0.10 to -0.01 SD; adjusted for confounding factors). After induction of labor, fewer children reached higher secondary school level (at 38 weeks 48% vs 54%; adjusted odds ratio [aOR] 0.88, 95% CI 0.82-0.94).

CONCLUSIONS

In women with uncomplicated pregnancies at term, consistently, at every week of gestation from 37 to 41 weeks, induction of labor is associated with lower offspring school performance at age 12 and lower secondary school level compared with non-intervention, although residual confounding may remain. These long-term effects of induction of labor should be incorporated in counseling and decision making.

Predictive factors for vaginal delivery by induction of labor in uncomplicated pregnancies at 40-41 gestational weeks: A Japanese prospective single-center cohort study

AIM

We investigated cervical parameters predictive of vaginal delivery in elective labor induction among women at 40-41 gestational weeks.

METHODS

This Japanese prospective single-center cohort study was conducted between July 2019 and June 2020. We enrolled women with an uncomplicated singleton pregnancy who underwent labor induction at 40-41 gestational weeks. We analyzed background characteristics and cervical parameters, including Bishop score, cervical length, posterior cervical angle, and changes in cervical parameters before and after cervical dilatation. The endpoint was the rate of vaginal delivery.

RESULTS

Of 142 eligible participants, all 24 multiparous women underwent vaginal delivery. Among the nulliparous women (n = 118), the following categories showed significantly higher rates of vaginal delivery: Bishop scores of ≥6 before and after dilatation, compared with Bishop score <6 (adjusted prevalence ratio (aPR) [95% confidence interval (CI)]; 1.58 [1.17-2.13] and 1.56 [1.13-2.14], respectively) and cervical length of <10 and 10-20 mm before dilation, compared with cervical length of >30 mm (aPR [95% CI]; 1.47 [1.00-2.15] and 2.13 [1.42-3.18], respectively). The posterior cervical angle and other background characteristics showed no significant associations. Furthermore, women with cervical lengths of ≥20 mm before and <20 mm after dilatation showed a higher rate of vaginal delivery, compared to cervical length of ≥20 mm even after dilatation (aPR [95% CI]; 1.95 [1.19-3.20]).

CONCLUSIONS

High Bishop score, short cervical length, and changes in cervical length with dilatation are potential independent predictors of vaginal delivery following elective labor induction in nulliparous women at 40-41 gestational weeks.

Is gestational age at term a risk factor for ongoing pregnancies in nulliparous women: A prospective cohort study

BACKGROUND

The results of American observational studies and 1 large, randomized trial show that elective induction of labor among nulliparous women can reduce cesarean delivery rates and suggest that gestational age at delivery may be a risk factor for cesarean delivery in pregnancies managed expectantly. However, data on the risk of cesarean delivery at term in ongoing pregnancies are sparse, especially in high-income countries, and further information is needed to explore the external validity of these previous studies.

OBJECTIVE

This study aimed to evaluate the risk of cesarean delivery for each gestational week of ongoing pregnancy in nulliparous women with a singleton fetus in the cephalic presentation at term in a French population.

STUDY DESIGN

This retrospective study was conducted in a perinatal network of 10 maternity units from January 1, 2016, to December 31, 2017, and included all nulliparous women with a singleton fetus in the cephalic presentation who gave birth at term (≥37 0/7 weeks of gestation). From the start of term (37 completed weeks) and at the start of each subsequent week of completed gestation (each week + 0 days), ongoing pregnancy was defined as that of a woman who was still pregnant and who gave birth at any time after that date. For each week of gestation for these ongoing pregnancies, the cesarean delivery rate was defined as the number of cesarean deliveries performed in each ongoing pregnancy group divided by the number of women in this group. Separate models for each week of gestation, adjusted by maternal characteristics and hospital status, were used to compare the cesarean delivery risk between ongoing pregnancies and those delivered the preceding week. The same methods were applied to subgroups defined according to the mode of labor onset. Odds ratios were calculated after adjusting for maternal age and educational level, presence of severe preeclampsia, and maternity unit status.

RESULTS

The study included 11,308 nulliparous women, 2544 (22.5%) of whom had a cesarean delivery. These rates remained stable for ongoing pregnancies at 37 0/7, 38 0/7, and 39 0/7 weeks of gestation; the rates were 22.5% (95% confidence interval, 21.7-23.2), 22.6% (95% confidence interval, 21.8-23.3); and 22.7% (95% confidence interval, 21.9-23.6), respectively. The risk of cesarean delivery started to increase in ongoing pregnancies at 40 0/7 weeks of gestation (24.3%; 95% confidence interval, 23.1-25.4) and especially at 41 0/7 weeks of gestation (30.7%; 95% confidence interval, 28.9-32.5). Similar trends were also shown for all modes of labor onset and in every maternity unit. In univariate and multivariate analyses, ongoing pregnancy at or beyond 40 0/7 weeks of gestation was associated with a higher risk of cesarean delivery than pregnancy delivered the previous week: 24.3% of ongoing pregnancies at 40 0/7 weeks of gestation vs 19.9% of deliveries between 39 0/7 weeks of gestation and 39 6/7 weeks of gestation. The odds ratios were 1.28 (95% confidence interval, 1.15-1.44) or 30.4% of ongoing pregnancies at 41 0/7 weeks of gestation vs 1.73 (95% confidence interval, 1.51-1.96) or 19.6% of deliveries between 40 0/7 weeks of gestation and 40 6/7 weeks of gestation.

CONCLUSION

Cesarean delivery rates increased starting at 40 0/7 weeks of gestation in ongoing pregnancies regardless of the mode of labor onset.

Trends in labor induction indications: A 20-year population-based study

INTRODUCTION

Use of labor induction has increased rapidly in most middle- and high-income countries over the past decade. The reasons for the stark rise in labor induction are largely unknown. We aimed to assess the extent to which the rising rate of labor induction is explained by changes in rates of underlying indications over time.

MATERIAL AND METHODS

The study was based on nationwide data from the Icelandic Medical Birth Register on 85 620 singleton births from 1997 to 2018. The rate of labor induction and indications for induction was calculated for all singleton births in 1997-2018. Change over time was expressed as relative risk (RR), using Poisson regression with 95% confidence intervals (CI) adjusted for maternal characteristics and indications for labor induction.

RESULTS

The crude rate of labor induction rose from 12.5% in 1997-2001 to 23.9% in 2014-2018 (crude RR = 1.91, 95% CI 1.81-2.01). While adjusting for maternal characteristics had little impact, adjusting additionally for labor induction indications lowered the RR to 1.43 (95% CI 1.35-1.51). Induction was increasingly indicated from 1997-2001 to 2014-2018 by gestational diabetes (2.4%-16.5%), hypertensive disorders (7.0%-11.1%), prolonged pregnancy (16.2%-23.7%), concerns for maternal wellbeing (3.2%-6.9%) and maternal age (0.5%-1.2%). No indication was registered for 9.2% of inductions in 2014-2018 compared with 16.3% in 1997-2001.

CONCLUSIONS

Our results show that the increase in labor induction over the study period is largely explained by an increase in various underlying conditions indicating labor induction. However, indications for 9.2% of labor inductions remain unexplained and warrant further investigation.

Analysis of Variables that Influence the Success Rates of Induction of Labor with Misoprostol: A Retrospective Observational Study

OBJECTIVE

 Determine the predictive criteria for success in inducing labor for live fetuses using misoprostol in pregnant women. Secondarily, the objective is to determine the rates of vaginal or cesarean delivery, duration of induction, interval of administration of misoprostol, the main causes of induction of labor and indication for operative delivery.

METHODS

 Medical records of 873 pregnant women admitted for cervical maturation from January 2017 to December 2018 were reviewed in a descriptive observational study of retrospective analysis, considering the following response variables: age, parity, Bishop Index, doses of misoprostol, labor induction time. Logistic regression models were used to predict success with misoprostol in non-operative deliveries.

RESULTS

 Of the 873 patients evaluated, 72% evolved with vaginal delivery, 23% of the cases were cesarean, 5% forceps or vacuum-extractor. For non-operative delivery the predictive variables at admission were age, parity, gestational age and dilation. During hospitalization, fewer vaginal touches, amniotomy or amniorrhexis with clear fluid lead to a shorter induction time and a greater chance of non-operative delivery. False positives and false negatives of the model were always below 50% and correct answers above 65%.

CONCLUSION

 At admission, age less than 24 years, previous normal births, lower the gestational age and greater the dilation, were predictive of greater probability of non-operative delivery. During hospitalization, the less vaginal touches and occurrence of amniotomy/amniorrhexis with clear liquid indicate shorter induction time. Future studies with a prospective design and analysis of other factors are necessary to assess the replicability, generalization of these findings.

Induction of labor and nulliparity: A nationwide clinical practice pilot evaluation

INTRODUCTION

Induction of labor has become an increasingly common obstetric procedure, but in nulliparous women or women with a previous cesarean section, it can pose a clinical challenge. Despite an overall expansion of medical indications for labor induction, there is little international consensus regarding the criteria for induction, or for the recommended methods among nulliparous women. In this light, we assessed variations in the practice of induction of labor among 21 birth units in a nationwide cohort of women with no prior vaginal birth.

MATERIAL AND METHODS

We carried out a prospective observational pilot study of women with induced labor and no prior vaginal birth, across 21 Norwegian birth units. We registered induction indications, methods and outcomes from 1 September to 31 December 2018 using a web-based case record form. Women were grouped into "Nulliparous term cephalic", "Previous cesarean section" and "Other Robson" (Robson groups 6, 7, 8 or 10).

RESULTS

More than 98% of eligible women (n=1818) were included and a wide variety of methods was used for induction of labor. In nulliparous term cephalic pregnancies, cesarean section rates ranged from 11.1% to 40.6% between birth units, whereas in the previous cesarean section group, rates ranged from 22.7% to 67.5%. The indications "large fetus" and "other fetal" indications were associated with the highest cesarean rates. Failed inductions and failure to progress in labor contributed most to the cesarean rates. Uterine rupture occurred in two women (0.11%), both in the previous cesarean section group. In neonates, 1.6% had Apgar <7 at 5 minutes, and 0.4% had an umbilical artery pH <7.00.

CONCLUSIONS

Cesarean rates and applied methods for induction of labor varied widely in this nationwide cohort of women without a prior vaginal birth. Neonatal outcomes were similar to those of normal birth populations. Results could indicate the need to move towards more standardized induction protocols associated with optimal outcomes for mother and baby.

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.