Maternal and neonatal outcomes in electively induced low-risk term pregnancies

Association between timing of labor induction and neonatal and maternal outcomes: an observational study from China

BACKGROUND

Growing evidence suggests that elective induction of labor at 39 weeks' gestation may lead to more favorable perinatal outcomes than expectant management, however, how to weigh the pros and cons of elective labor induction at 39 weeks, the expectation of spontaneous delivery at 40 or 41 weeks, or delayed labor induction at 40 or 41 weeks on neonatal and maternal outcomes remains a practical challenge in clinical decision-making.

OBJECTIVE

We compared the neonatal and maternal outcomes between elective induction of labor at 39 weeks' gestation and expectant management in a real-world setting. We also divided the expectantly managed group and compared outcomes of the spontaneous delivery at 40 or 41 weeks' gestation group and the induced group at 40 or 41 weeks' gestation with those of the elective induction at 39 weeks' gestation group.

STUDY DESIGN

This retrospective cohort study included 21,282 participants who delivered between January 1, 2019, and June 30, 2022. Participants were initially categorized into 3 groups at 39 weeks' gestation, namely elective induction of labor, spontaneous delivery, and expectant management, for the primary analysis in which elective induction was compared with expectant management. Subsequently, the expectant management group at 39 weeks' gestation was divided into 3 groups at 40 weeks, and participants who underwent expectant management at 40 weeks were then divided into 2 groups at 41 weeks' gestation, namely elective induction and spontaneous delivery. In total, 6 groups were compared in the secondary analysis with the elective induction at 39 weeks' gestation group serving as the reference group.

RESULTS

At 39 weeks' gestational age, participants who underwent elective induction of labor had a significantly lower risk for the primary composite outcomes than participants who were managed expectantly (adjusted odds ratio, 0.72; 95% confidence interval, 0.55-0.95), and there was no significant difference in the risk for cesarean delivery between the 2 groups. After further dividing the expectantly managed group and comparing them with participants who underwent elective induction of labor at 39 weeks' gestation, those who underwent spontaneous delivery at 40 weeks' gestation had significantly lower risks for cesarean delivery (0.61; 0.52-0.71) and chorioamnionitis (0.78; 0.61-1.00) but a higher risk for fetal distress (1.39; 1.22-1.57); those with spontaneous delivery at 41 weeks' gestation had a significantly higher risk for fetal distress (1.44; 1.16-1.79), postpartum hemorrhage (1.83; 1.26-2.66), and prolonged or arrested labor (1.61; 1.02-2.54). Moreover, when compared with participants who underwent elective induction of labor at 39 weeks' gestation, participants who were induced later in gestation had significantly higher risks for adverse neonatal and maternal outcomes, especially at 40 weeks' gestation.

CONCLUSION

Our findings indicate that elective induction of labor at 39 weeks' gestation was significantly associated with lower risks for adverse short-term neonatal and maternal outcomes when compared with expectant management. Moreover, our study highlights the nuanced trade-offs in risks and benefits between elective induction at 39 weeks' gestation and waiting for spontaneous labor or delayed induction at 40 or 41 weeks' gestation, thus providing valuable insights for clinical decision-making in practice.

Induction of labor vs expectant management among low-risk patients with 1 prior cesarean delivery

BACKGROUND

Studies that have compared induction of labor in individuals with 1 prior cesarean delivery to expectant management have shown conflicting results.

OBJECTIVE

To determine the association between clinical outcomes and induction of labor at 39 weeks in a national sample of otherwise low-risk patients with 1 prior cesarean delivery.

STUDY DESIGN

This cross-sectional study analyzed 2016 to 2021 US Vital Statistics birth certificate data. Individuals with vertex, singleton pregnancies, and 1 prior cesarean delivery were included. Patients with prior vaginal deliveries, delivery before 39 weeks 0 days or after 42 weeks 6 days of gestation, and medical comorbidities were excluded. The primary exposure of interest was induction of labor at 39 weeks 0 days to 39 weeks 6 days compared to expectant management with delivery from 40 weeks 0 days to 42 weeks 6 days. The primary outcome was vaginal delivery. The main secondary outcomes were separate maternal and neonatal morbidity composites. The maternal morbidity composite included uterine rupture, operative vaginal delivery, peripartum hysterectomy, intensive care unit admission, and transfusion. The neonatal morbidity composite included neonatal intensive care unit admission, Apgar score less than 5 at 5 minutes, immediate ventilation, prolonged ventilation, and seizure or serious neurological dysfunction. Unadjusted and adjusted log binomial regression models accounting for demographic variables and the exposure of interest (induction vs expectant management) were performed. Results are presented as unadjusted and adjusted risk ratios with 95% confidence intervals.

RESULTS

From 2016 to 2021, a total of 198,797 individuals with vertex, singleton pregnancies, and 1 prior cesarean were included in the primary analysis. Of these individuals, 25,915 (13.0%) underwent induction of labor from 39 weeks 0 days to 39 weeks 6 days and 172,882 (87.0%) were expectantly managed with deliveries between 40 weeks 0 days and 42 weeks 6 days. In adjusted analyses, patients induced at 39 weeks were more likely to have a vaginal delivery when compared to those expectantly managed (38.0% vs 31.8%; adjusted risk ratio 1.32, 95% confidence interval 1.28, 1.36). Among those who had vaginal deliveries, induction of labor was associated with increased likelihood of operative vaginal delivery (11.1% vs 10.0; adjusted risk ratio 1.15, 95% confidence interval 1.07, 1.24). The maternal morbidity composite occurred in 0.9% of individuals in both the induction and expectant management groups (adjusted risk ratio 0.92, 95% confidence interval 0.79, 1.06). The rates of uterine rupture (0.3%), peripartum hysterectomy (0.04% vs 0.05%), and intensive care unit admission (0.1% vs 0.2%) were all relatively low and did not differ significantly between groups. There was also no significant difference in the neonatal morbidity composite between the induction and expectant management groups (7.3% vs 6.7%; adjusted risk ratio 1.04, 95% confidence interval 0.98, 1.09).

CONCLUSION

When compared to expectant management, elective induction of labor at 39 weeks in low-risk patients with 1 prior cesarean delivery was associated with a significantly higher likelihood of vaginal delivery with no difference in composite maternal and neonatal morbidity outcomes. Prospective studies are needed to better elucidate the risks and benefits of induction of labor in this patient population.

Elective induction of labor versus expectant management at 39 weeks among low-risk nulliparous pregnant women: A randomized controlled trial in India (ELITE-39 trial)

OBJECTIVE

The aim of the present open label randomized controlled trial was to compare the rate of cesarean section (CS) after elective induction with that of expectant management in low-risk nulliparous women at 39 weeks.

METHODS

This randomized controlled trial from a tertiary maternity care center enrolled low risk nulliparous pregnant women at 38-38+4 weeks between April 1, 2019 and December 31, 2021. Participants were randomized into either the elective induction group (e-IOL) or the expectant management (EM) group though computer generated block randomization. The primary outcome was cesarean rate and the secondary outcome include adverse maternal and perinatal outcome between e-IOL and EM groups. We performed intention to treat analysis.

RESULTS

A total of 360 women were enrolled into the present study. Analysis was performed for 179 women in the e-IOL group and 180 women in the EM group. The baseline demographic characteristics including Bishop score were comparable between the groups. The CS rate in both groups was 17.3% (31/179) and 25% (45/180), which is comparable (P = 0.08). There was one intrapartum stillbirth in the e-IOL group, and two babies succumbed in the neonatal period in the EM group. The maternal and perinatal outcomes between the groups were not found to be significantly different.

CONCLUSION

Elective induction of low-risk nulliparous women at 39 weeks was not associated with increased cesarean section rate. The maternal and perinatal outcomes were comparable. Large, multicentric real time randomized controlled trials are needed to understand the benefit of elective induction in low-risk nulliparous women. This should include centers with large volume of deliveries especially from emerging countries also.

Placental pathology and neonatal morbidity: exploring the impact of gestational age at birth

AIM

To evaluate placental pathology in term and post-term births, investigate differences in clinical characteristics, and assess the risk of adverse neonatal outcome.

METHODS

This prospective observational study included 315 singleton births with gestational age (GA) > 36 weeks + 6 days meeting the local criteria for referral to placental histopathologic examination. We applied the Amsterdam criteria to classify the placentas. Births were categorized according to GA; early-term (37 weeks + 0 days to 38 weeks + 6 days), term (39 weeks + 0 days to 40 weeks + 6 days), late-term (41 weeks + 0 days to 41 weeks + 6 days), and post-term births (≥ 42 weeks + 0 days). The groups were compared regarding placental pathology findings and clinical characteristics. Adverse neonatal outcomes were defined as 5-minute Apgar score < 7, umbilical cord artery pH < 7.0, admission to the neonatal intensive care unit or intrauterine death. A composite adverse outcome included one or more adverse outcomes. The associations between placental pathology, adverse neonatal outcomes, maternal and pregnancy characteristics were evaluated by logistic regression analysis.

RESULTS

Late-term and post-term births exhibited significantly higher rates of histologic chorioamnionitis (HCA), fetal inflammatory response, clinical chorioamnionitis (CCA) and transfer to neonatal intensive care unit (NICU) compared to early-term and term births. HCA and maternal smoking in pregnancy were associated with adverse outcomes in an adjusted analysis. Nulliparity, CCA, emergency section and increasing GA were all significantly associated with HCA.

CONCLUSIONS

HCA was more prevalent in late and post-term births and was the only factor, along with maternal smoking, that was associated with adverse neonatal outcomes. Since nulliparity, CCA and GA beyond term are associated with HCA, this should alert the clinician and elicit continuous intrapartum monitoring for timely intervention.

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.

Breech presentation induction compared to cephalic presentation: Effectiveness and characteristics

INTRODUCTION

The objective of our study was to compare the effectiveness of induction in cephalic presentations to that of breech presentations as well as the characteristics of the latter and the maternal-fetal morbidity and mortality.

MATERIAL AND METHODS

This was a single-center retrospective study carried out at the Lille University Hospital in the Jeanne de Flandre Maternity Hospital including all patients with a breech fetus for whom an induction was indicated beyond 37 weeks of gestation between January 2014 and December 2020. A matching was performed to include 2 cephalic presentations for one breech presentation. The primary outcome was successful induction defined by two things: passage into the active phase (cervical dilatation > 5 cm) and vaginal delivery.

RESULTS

101 inductions of breech presentations were included and matched to 202 cephalic presentations. After adjustment by BISHOP score, there was no significant difference in the caesarean section rate between the two groups (25.7% in cephalic vs 33.7% in breech, OR 0.67 [CI95% 0.38-1.18]) or in the rate of transition to active phase (80.7% in cephalic vs 82.2% in breech, OR 1.26 [CI95% 0.65-2.44]). Post-partum blood loss was not significantly different between the two groups (14.4% in cephalic vs 12.9% in breech, OR 1.22 [CI95% 0.57-2.57]). Moderate neonatal acidosis was more frequent in the breech group (6,4% in cephalic vs 15,8% in breech, OR 3.04 [CI95% 1.38-6.71]).

CONCLUSION

Induction of breech births beyond 37 weeks of gestation appeared to be as effective as induction of cephalic presentations. There was no difference in the rate of caesarean section and transition to active labor. Maternal morbidity was not increased.

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.

Elective Induction of Labour at 39 Weeks Compared With Expectant Management in Nulliparous Persons Delivering in a Community Hospital

OBJECTIVE

To determine the impact of offering elective labour induction at 39 weeks gestation on perinatal and maternal outcomes in nulliparous people with low-risk pregnancies.

METHODS

The charts of all pregnant people who delivered at Brockville General Hospital between September 2018 and December 2021 were retrospectively reviewed. Perinatal and maternal outcomes of low-risk nulliparous pregnant people who underwent elective induction at 39 weeks and over were extracted and compared with those of low-risk nulliparous pregnant people who underwent expectant management. Exclusion criteria included multiparous people, high-risk pregnancies, multiple gestations, deliveries at less than 39 weeks gestation, and elective cesarean deliveries. Univariate and multivariate analysis was performed.

RESULTS

A total of 174 patients were included. Of these patients, 56 (32.2%) underwent elective induction of labour between 39⁰ and 39⁶ weeks gestation over the period of June 2020 to December 2021, whereas 118 (67.8%) were expectantly managed from 39⁰ weeks gestation over the period of September 2018 to March 2020. Compared with expectant management, those in the 39⁺ weeks induction group had a significantly lower risk of cesarean delivery (odds ratio [OR] 0.39; 95% confidence interval [CI] 0.15-0.99), composite adverse maternal outcomes (OR 0.34; 95% CI 0.12-0.97), and composite adverse perinatal outcomes (OR 0.26; 95% CI 0.074-0.92).

CONCLUSION

Our results suggest that elective induction of labour at 39 weeks gestation and over in low-risk nulliparous people is associated with lower risks of cesarean delivery, composite adverse maternal outcomes, and composite adverse perinatal outcomes than expectant management.

Traction vs no traction in Foley catheter use for induction of labor: a systematic review and meta-analysis of randomized trials

OBJECTIVE

Intracervical Foley catheter is a safe and effective method for cervical ripening. There are a variety of ways to modify this ripening method, including adding traction or tension to the catheter. The utility of this practice is uncertain. The aim of this systematic review and meta-analysis of randomized controlled trials was to investigate whether the placement of traction vs no traction on a Foley catheter during cervical ripening decreases total time from induction to delivery.

DATA SOURCES

Electronic sources include MEDLINE, Scopus, ClinicalTrials.gov, the International Prospective Register of Systematic Reviews, SciELO, the Cochrane Central Register of Controlled Trials, and Google Scholar from inception through June 2020.

STUDY ELIGIBILITY CRITERIA

Randomized trials comparing Foley catheter with traction (ie, intervention) vs Foley catheter without traction (ie, control) for cervical ripening were included in the meta-analysis. All types of traction were analyzed (weighted, taped to thigh) and whether the traction was placed only initially at Foley catheter placement or repeated throughout the ripening process.

METHODS

The primary outcome was the mean time from induction to delivery in hours. Meta-analysis was performed using the random-effects model of DerSimonian and Laird to produce summary treatment effects in terms of mean difference with 95% confidence interval. Heterogeneity was measured using I-squared (Higgins I²).

RESULTS

Three trials including 790 singleton gestations were identified as relevant and included in the systematic review. Women randomized to traction on the Foley balloon had a similar time from induction to delivery compared with no traction (mean difference, 0.25; confidence interval, -0.78 to 1.27). No significant differences were found in the secondary outcomes. There was no difference in cesarean delivery between groups (relative risk, 0.94; 95% confidence interval, 0.74-1.19). Foley catheter expulsion was faster in the tension group (mean difference, -3.74; 95% confidence interval, -6.29 to -1.19) CONCLUSION: Adding traction to an intracervical Foley catheter during cervical ripening does not decrease time to delivery.

Labor Induction at 39 Weeks Compared with Expectant Management in Low-Risk Parous Women

OBJECTIVE

Our objective was to compare outcomes among low-risk parous women who underwent elective labor induction at 39 weeks versus expectant management.

STUDY DESIGN

This is a secondary analysis of an observational cohort of 115,502 mother-infant dyads who delivered at 25 hospitals between 2008 and 2011. The inclusion criteria for this analysis were low-risk parous women with nonanomalous singletons with at least one prior vaginal delivery after 20 weeks, who delivered at ≥39^0/7 weeks. Women who electively induced between 39^0/7 and 39^6/7 weeks were compared with women who expectantly managed ≥39^0/7 weeks. The primary outcome for this analysis was cesarean delivery. Secondary outcomes were composites of maternal adverse outcome and neonatal adverse outcome. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR).

RESULTS

Of 20,822 women who met inclusion criteria, 2,648 (12.7%) were electively induced at 39 weeks. Cesarean delivery was lower among women who underwent elective induction at 39 weeks than those who did not (2.4 vs. 4.6%, adjusted odds ratio [aOR]: 0.70, 95% confidence interval [CI]: 0.53-0.92). The frequency of the composite maternal adverse outcome was significantly lower for the elective induction cohort as well (1.6 vs. 3.1%, aOR: 0.66, 95% CI: 0.47-0.93). The composite neonatal adverse outcome was not significantly different between the two groups (0.3 vs. 0.6%; aOR: 0.60, 95% CI: 0.29-1.23).

CONCLUSION

In low-risk parous women, elective induction of labor at 39 weeks was associated with decreased odds of cesarean delivery and maternal morbidity, without an increase in neonatal adverse outcomes.

KEY POINTS

· 39-week elective induction is associated with decreased cesarean delivery in low-risk parous women.. · Compared with expectant management, maternal adverse outcomes were lower with elective induction.. · Neonatal adverse outcomes are unchanged between elective and expectant management groups..

Induction of labor or expectant management? Birth outcomes for nulliparous individuals choosing midwifery care

BACKGROUND

Induction of labor (IOL) has been studied as a strategy to reduce rates of cesarean birth (CB). Midwifery care models are also associated with lower CB rates, even considering that midwives perform fewer IOLs. In this study, we examined childbirth outcomes among individuals undergoing IOL in certified nurse-midwifery (CNM) care as compared to two categories of expectant management (EM).

METHODS

Data were from two CNM practices in the United States (2007-2018). The sample was limited to term nulliparous, nondiabetic, singleton, vertex pregnancies. Individuals having an IOL in each week of gestation (37th, 38th, etc) were compared with those having EM. Two methods for defining EM were considered as each method when used alone limits interpretation. Inclusive EM included all births starting in the same week as IOL. The exclusive EM group was comprised of all births occurring in the next gestational age week relative to the IOL cases (ie, 39th week IOL versus all births occurring at 40 weeks or later). Adjusted regression models were used to examine differences in CB by IOL versus EM (inclusive or exclusive) at each week of gestation.

RESULTS

Among 4057 CNM-attended pregnancies, the overall rate of IOL was 28.9% (95% CI 27.5%-30.3%) and CB was 19.4% (95% CI 18.1%-20.6%). Most IOLs involved obstetric indications. CB rates did not differ by IOL versus inclusive EM when performed between 37 and 40 weeks, though post hoc power calculations indicate these comparisons were low-powered. In multivarable models, IOL in the 40th week was associated with lower odds for CB versus exclusive EM definition (ie, births occurring at 41 0/7 weeks or later, OR (95% CI) = 0.57 (0.36-0.90)). This finding is explained by the large increase in CB rates after IOL during the 41st week (34.3%, up from 21.9% in the 40th week). Furthermore, the adjusted odds for CB in the 41st week were 55% higher relative to inclusive EM (all labors 41st week and later), OR (95% CI) = 1.55(1.11-2.15). Neonatal outcomes (aside from macrosomia) did not differ by IOL/EM at any gestational age.

DISCUSSION

Outcomes for nulliparous individuals having IOL or EM in the context of a midwifery model of care include low overall use of CB and low frequency of IOL before 41 weeks. In this model, IOL in the 40th week may lower CB odds, especially in comparison to those who do not have spontaneous labor and later undergo an IOL in the 41st week.

Prospective cohort study of induction of labor: Indications, outcome and postpartum hemorrhage

INTRODUCTION

This study was undertaken because of the increasing rate of induction of labor (IOL) in our hospital and its associated higher caesarean section (CS) rates. The objective was to ascertain the incidence, indications, methods, outcome, and complications of IOL, in particular postpartum hemorrhage.

METHODS

This was a prospective observational cohort study of women who underwent IOL in a medium-sized district general hospital. Blood loss was measured by the gravimetric method and correlated to postpartum hemoglobin level within 48 hours of birth.

RESULTS

A total of 445 women needed IOL (incidence 33%). Common indications were: small for gestational age (SGA) or fetal growth restriction (FGR) (18%), spontaneous rupture of membrane (17%), reduced fetal movement (16%), prolonged pregnancy (15%), and diabetes (13%). In all, 67% women achieved spontaneous vaginal delivery and 18% underwent caesarean section. With regard to blood loss, 62 women (14%) had postpartum hemorrhage (PPH) of >1000 mL and 22 women (4.9%) had a blood loss >1500 mL. The caesarean section rate was higher than the overall emergency caesarean section rate in that year. Incidence of PPH in this cohort was higher than the normal incidence.

CONCLUSIONS

Increasing trend of induction of labor (IOL) is due to the changing clinical policy on management of small for gestational age babies, spontaneous rupture of membrane, reduced fetal movement and other complications of pregnancy. There is conflicting evidence on the effect of IOL on caesarean section rates. IOL is a risk factor for PPH. Accurate measurement of blood loss is essential in detecting a fall in hemoglobin which in turn helps in the appropriate management of PPH.

Adverse Outcomes among Low-Risk Pregnancies at 39 to 41 Weeks: Stratified by Birth Weight Percentile

OBJECTIVE

This study aimed to assess the risk of adverse outcomes among low-risk pregnancies at 39 to 41 weeks, stratified by birth weight percentile.

STUDY DESIGN

This retrospective cohort study utilized the U.S. vital statistics datasets (2013-2017) and evaluated low-risk women with nonanomalous cephalic singleton gestations who labored and delivered at 39 to 41 weeks, regardless of ultimate mode of delivery. Newborns were categorized as small (<10th percentile), large (>90th percentile), or appropriate (10-90th percentile) for gestational ages (SGA, LGA, and AGA, respectively). The primary outcome, composite neonatal adverse outcome (CNAO), included Apgar's score <5 at 5 minutes, assisted ventilation >6 hours, seizure, or neonatal death. The secondary outcome, composite maternal adverse outcome (CMAO), included intensive care unit admission, blood transfusion, uterine rupture, or unplanned hysterectomy. Multivariable Poisson's regression was used to estimate the association (using adjusted relative risk [aRR] and 95% confidence interval [CI]).

RESULTS

Of 19.8 million live births during the study interval, approximately 8.9 million (44.9%) met the inclusion criteria, with 9.9% being SGA, 9.2% being LGA, and 80.9% being AGA. SGA newborns delivered at 40 (aRR = 1.17; 95% CI: 1.12-1.23) and at 41 weeks (aRR = 1.55; 95% CI: 1.45-1.66) had a higher risk of CNAO than at 39 weeks. Similarly, LGA newborns delivered at 40 (aRR = 1.13; 95% CI: 1.07-1.19) and 41 weeks (aRR = 1.44; 95% CI: 1.35-1.54) and AGA newborns delivered at 40 (aRR = 1.24; 95% CI: 1.21-1.26) and 41 weeks (aRR = 1.57; 95% CI: 1.53-1.61) also had a higher risk of CNAO than at 39 weeks. CMAO was also significantly higher at 40 and 41 weeks than at 39 weeks, regardless of whether the mothers delivered SGA, LGA, or AGA newborns.

CONCLUSION

Among low-risk pregnancies, the risks of composite neonatal and maternal adverse outcomes increase from 39 through 41 weeks' gestation, irrespective of whether newborns are SGA, LGA, or AGA.

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.

Late Pregnancy Ultrasound to Screen for and Manage Potential Birth Complications in Nulliparous Women: A Cost-Effectiveness and Value of Information Analysis

BACKGROUND

Fetal growth restriction is a major risk factor for stillbirth. A routine late-pregnancy ultrasound scan could help detect this, allowing intervention to reduce the risk of stillbirth. Such a scan could also detect fetal presentation and predict macrosomia. A trial powered to detect stillbirth differences would be extremely large and expensive.

OBJECTIVES

It is therefore critical to know whether this would be a good investment of public research funds. The aim of this study is to estimate the cost-effectiveness of various late-pregnancy screening and management strategies based on current information and predict the return on investment from further research.

METHODS

Synthesis of current evidence structured into a decision model reporting expected costs, quality-adjusted life-years, and net benefit over 20 years and value-of-information analysis reporting predicted return on investment from future clinical trials.

RESULTS

Given a willingness to pay of £20 000 per quality-adjusted life-year gained, the most cost-effective strategy is a routine presentation-only scan for all women. Universal ultrasound screening for fetal size is unlikely to be cost-effective. Research exploring the cost implications of induction of labor has the greatest predicted return on investment. A randomized, controlled trial with an endpoint of stillbirth is extremely unlikely to be a value for money investment.

CONCLUSION

Given current value-for-money thresholds in the United Kingdom, the most cost-effective strategy is to offer all pregnant women a presentation-only scan in late pregnancy. A randomized, controlled trial of screening and intervention to reduce the risk of stillbirth following universal ultrasound to detect macrosomia or fetal growth restriction is unlikely to represent a value for money investment.

Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis

BACKGROUND

Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

OBJECTIVES

We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. The main questions addressed were the diagnostic effectiveness of universal late pregnancy ultrasound to predict adverse outcomes and the cost-effectiveness of either implementing universal ultrasound or conducting further research in this area.

DESIGN

We performed diagnostic test accuracy reviews of five ultrasonic measurements in late pregnancy. We conducted cost-effectiveness and value-of-information analyses of screening for fetal presentation, screening for small for gestational age fetuses and screening for large for gestational age fetuses. Finally, we conducted a survey and a focus group to determine the willingness of women to participate in a future randomised controlled trial.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane Library from inception to June 2019.

REVIEW METHODS

The protocol for the review was designed a priori and registered. Eligible studies were identified using keywords, with no restrictions for language or location. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Health economic modelling employed a decision tree analysed via Monte Carlo simulation. Health outcomes were from the fetal perspective and presented as quality-adjusted life-years. Costs were from the perspective of the public sector, defined as NHS England, and the costs of special educational needs. All costs and quality-adjusted life-years were discounted by 3.5% per annum and the reference case time horizon was 20 years.

RESULTS

Umbilical artery Doppler flow velocimetry, cerebroplacental ratio, severe oligohydramnios and borderline oligohydramnios were all either non-predictive or weakly predictive of the risk of neonatal morbidity (summary positive likelihood ratios between 1 and 2) and were all weakly predictive of the risk of delivering a small for gestational age infant (summary positive likelihood ratios between 2 and 4). Suspicion of fetal macrosomia is strongly predictive of the risk of delivering a large infant, but it is only weakly, albeit statistically significantly, predictive of the risk of shoulder dystocia. Very few studies blinded the result of the ultrasound scan and most studies were rated as being at a high risk of bias as a result of treatment paradox, ascertainment bias or iatrogenic harm. Health economic analysis indicated that universal ultrasound for fetal presentation only may be both clinically and economically justified on the basis of existing evidence. Universal ultrasound including fetal biometry was of borderline cost-effectiveness and was sensitive to assumptions. Value-of-information analysis indicated that the parameter that had the largest impact on decision uncertainty was the net difference in cost between an induced delivery and expectant management.

LIMITATIONS

The primary literature on the diagnostic effectiveness of ultrasound in late pregnancy is weak. Value-of-information analysis may have underestimated the uncertainty in the literature as it was focused on the internal validity of parameters, which is quantified, whereas the greatest uncertainty may be in the external validity to the research question, which is unquantified.

CONCLUSIONS

Universal screening for presentation at term may be justified on the basis of current knowledge. The current literature does not support universal ultrasonic screening for fetal growth disorders.

FUTURE WORK

We describe proof-of-principle randomised controlled trials that could better inform the case for screening using ultrasound in late pregnancy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017064093.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 15. See the NIHR Journals Library website for further project information.

Neonatal and Maternal Composite Adverse Outcomes Among Low-Risk Nulliparous Women Compared With Multiparous Women at 39-41 Weeks of Gestation

OBJECTIVE

To estimate whether the frequency of adverse maternal and neonatal outcomes differs between low-risk nulliparous and multiparous women at 39-41 weeks of gestation.

METHODS

This is a secondary analysis of an observational obstetrics cohort of maternal-neonatal dyads at 25 hospitals. Low-risk women with nonanomalous singletons who delivered between 39 0/7 and 41 6/7 weeks of gestation were included. The composite neonatal adverse outcome included 5-minute Apgar score less than five, ventilator support or cardiopulmonary resuscitation, seizure, hypoxic ischemic encephalopathy, sepsis, bronchopulmonary dysplasia, persistent pulmonary hypertension, necrotizing enterocolitis, birth injury or perinatal death. The composite maternal adverse outcome included infection, third- or fourth-degree perineal laceration, thromboembolism, transfusion of blood products, or maternal death. Small for gestational age (SGA), large for gestational age (LGA), and shoulder dystocia requiring maneuvers were also evaluated. Multivariable regression was used to estimate adjusted relative risks (aRRs) and adjusted odds ratios (aORs) with 95% CIs.

RESULTS

Of the 115,502 women in the overall cohort, 39,870 (34.5%) met eligibility criteria for this analysis; 18,245 (45.8%) were nulliparous. The risk of the composite neonatal adverse outcome (1.5% vs 1.0%, aRR 1.80, 95% CI 1.48-2.19), composite maternal adverse outcome (15.1% vs 3.3%, aRR 5.04, 95% CI 4.62-5.49), and SGA (8.9% vs 5.8%, aOR 1.45, 95% CI 1.33-1.57) was significantly higher in nulliparous than multiparous patients. The risk of LGA (aOR 0.65, 95% CI 0.60-0.71) and shoulder dystocia with maneuvers (aRR 0.68, 95% CI 0.60-0.77) was significantly lower in nulliparous rather than multiparous patients.

CONCLUSION

The risk of composite adverse outcomes and SGA among low-risk nulliparous women at 39-41 weeks of gestation is significantly higher than among multiparous counterparts. However, nulliparous women had a lower risk of shoulder dystocia with maneuvers and LGA.

Elective Labor Induction at 39 Weeks of Gestation Compared With Expectant Management: Factors Associated With Adverse Outcomes in Low-Risk Nulliparous Women

OBJECTIVE

To evaluate characteristics associated with adverse outcomes in low-risk nulliparous women randomized to elective labor induction at 39 weeks of gestation or expectant management.

METHODS

We conducted a secondary analysis of women randomized during the 38th week to induction at 39 weeks of gestation or expectant management. Deliveries before 39 weeks of gestation and those not adherent to study protocol or with fetal anomalies were excluded. A composite of adverse outcomes (perinatal death or severe neonatal complications), third- or fourth-degree lacerations, and postpartum hemorrhage were evaluated. Log binomial regression models estimated relative risks and 95% CIs for associations of outcomes with patient characteristics including randomly assigned treatment group. Interactions between patient characteristics and treatment group were tested.

RESULTS

Of 6,096 women with outcome data, 5,007 (82.1%) met criteria for inclusion in this analysis. Frequency of the perinatal composite was 252 (5.0%), 166 (3.3%) for third- or fourth-degree perineal laceration, and 237 (4.7%) for postpartum hemorrhage. In multivariable analysis, intended labor induction at 39 weeks of gestation was associated with a reduced perinatal composite outcome (4.1% vs 6.0%; adjusted relative risk [aRR] 0.71; 95% CI 0.55-0.90), whereas increasing body mass index (BMI) was associated with an increased perinatal composite outcome (aRR 1.04/unit increase; 95% CI 1.02-1.05). Decreased risk of third- or fourth-degree perineal laceration was observed with increasing BMI (aRR 0.96/unit increase; 95% CI 0.93-0.98) and in Black women compared with White women (1.2% vs 3.9%; aRR 0.34; 95% CI 0.19-0.60). Increased risk of postpartum hemorrhage was observed in Hispanic women compared with White women (6.3% vs 4.0%; aRR 1.64; 95% CI 1.18-2.29). Patient characteristics associated with adverse outcomes were similar between treatment groups (P for interaction >.05).

CONCLUSION

Compared with expectant management, intended induction at 39 weeks of gestation was associated with reduced risk of adverse perinatal outcome. Patient characteristics associated with adverse outcomes were few and similar between groups.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01990612.

Cesarean delivery after non-medically indicated induction of labor: A population-based study using different definitions of expectant management

INTRODUCTION

Most observational studies found that non-medically indicated induction of labor (IOL) is not associated with an increased risk of cesarean delivery compared with expectant management, defined as all births at a later gestation. However, given the higher rate of cesarean delivery at late term, this definition of the expectant management group might bias the results of observational studies in favor of IOL at early or full term when estimating the risk of short-term (eg up to 1 week) expectant management.

MATERIAL AND METHODS

We conducted a retrospective cohort study including 447 066 singleton term and post-term hospital births that occurred in Austria between 2008 and 2016. Multivariate logistic regression was used to test the association of IOL and cesarean delivery at each week of gestation from 37-41. Expectant management was either defined as all births at "next week or beyond" or "at next week".

RESULTS

Non-medically indicated IOL was associated with increased odds for cesarean delivery at 37 and 38 weeks, and reduced odds at 40 and 41 weeks. At 39 weeks, IOL resulted in comparable cesarean rates compared with expectant management defined as "next week or beyond" (17.2% vs 16.2%; adjusted odds ratio [OR] 0.93; 95% confidence interval [CI] 0.86-1.00; P = .059). However, when defined as births "at the next week", expectant management was associated with significantly reduced odds for cesarean delivery (13.6%; adjusted OR 0.76; 95% CI 0.70-0.82; P < .001). Comparison of the cesarean delivery rates for the two definitions of expectant management showed that the "next week and beyond" model underestimates the benefit of short-term expectant management by up to 1 week, particularly for IOL at weeks 38 and 39.

CONCLUSIONS

Our findings demonstrate that the definition of the expectant management group has a significant impact when analyzing the outcome of IOL in retrospective cohort studies. Non-medically indicated IOL is not an all-or-none choice between "elective" induction and indefinite expectant management. Thus, to define the control group as all births at the next week could be useful for clinical decision-making, as it allows to estimate the risks of expectant management until the next appointment compared with immediate IOL.

Delivery at 39 Weeks of Gestation: The Time Has Come

It has long been observed that neonates born between 39 and 40 gestational weeks have the best perinatal outcomes. What has not been known, until recently, is whether these ideal perinatal outcomes would be achieved in neonates whose delivery was brought on intentionally in this window by labor induction. Recent randomized trials and large observational cohorts have answered this question: labor induction, as compared with expectant management, lowers the rate of cesarean delivery (without increasing other adverse maternal outcomes) and improves perinatal outcomes. For those women still pregnant, delivery at 39 weeks of gestation would simultaneously lower the number of cesarean deliveries and reduce the number of stillbirths and neonatal deaths in the United States.

Association of Term Labor Induction vs Expectant Management With Child Academic Outcomes

IMPORTANCE

Although labor induction at 39 weeks of gestation has been shown to reduce the number of cesarean deliveries, compared with expectant management, without increasing neonatal morbidity in nulliparous, low-risk women, the association between induction at 39 weeks and longer-term childhood cognitive outcomes is not certain.

OBJECTIVE

To evaluate educational outcomes of children born by induction at 39 or 40 weeks compared with those whose mothers were expectantly managed beyond those weeks.

DESIGN, SETTING, AND PARTICIPANTS

This statewide cohort study was conducted in Rhode Island. The participants included children of nulliparous women who were born at 39 weeks of gestation or later and then completed third-grade math and reading tests during the 2014 to 2017 academic year. Data analysis was performed from July 2019 to October 2019.

EXPOSURES

Induction of labor compared with expectant management.

MAIN OUTCOMES AND MEASURES

Third-grade math and reading test scores and proficiency (based on achievement level) among children born after induction in the 39th or 40th week were compared with scores for those who remained in utero beyond that same gestational week. The hypothesis was that induction in the 39th or 40th week would not be associated with differences in math or reading scores or proficiency compared with expectant management past the 39th or 40th week of gestation.

RESULTS

Of the 6393 children meeting the inclusion criteria (mean [SD] age, 8.00 [0.22] years; 3208 boys [50.2%]; 376 [5.8%] black; 1280 [22.0%] Hispanic), 455 were delivered by induction in the 39th week and 610 were delivered by induction in the 40th week. There were no differences in mean math or reading test scores or in the frequency of math or reading proficiency between children delivered by induction at 39 or 40 weeks compared with those whose mothers were expectantly managed (overall mean [SD] math score, 744 [33]; overall mean [SD] reading score, 743 [38]; 2945 children [46%] achieved proficiency in math and 2833 [44%] achieved proficiency in reading). After adjusting for plausible confounders (race/ethnicity, maternal education, hypertension, diabetes, and socioeconomic status), induction continued to be associated with similar proficiency in math and reading compared with expectant management. For children born by induction at 39 weeks, the adjusted relative risks were 1.07 (95% CI, 0.97-1.18) for math proficiency and 0.98 (95% CI, 0.88-1.08) for reading proficiency. For children born by induction at 40 weeks, the adjusted relative risks were 0.97 (95% CI, 0.88-1.08) for math proficiency and 0.98 (95% CI, 0.89-1.08) for reading proficiency.

CONCLUSIONS AND RELEVANCE

These findings suggest that the offspring of nulliparous women for whom labor is induced at 39 or 40 weeks have similar third-grade educational outcomes compared with the offspring of mothers who underwent expectant management past those gestational ages.

Elective Induction of Labor in the 39th Week of Gestation Compared With Expectant Management of Low-Risk Multiparous Women

OBJECTIVE

To compare perinatal and maternal outcomes in low-risk multiparous women who underwent elective induction of labor in the 39th week of gestation with those who were expectantly managed.

METHODS

We performed a single center retrospective cohort study of low-risk multiparous women delivering nonanomalous singletons between 39 and 42 completed weeks of gestation from 2014 to 2018. The primary outcome was a perinatal composite of death, neonatal respiratory support, a 5-minute Apgar score of 3 or less, and shoulder dystocia. Groups were compared using χ, Fisher exact, two sample t-test, and Wilcoxon rank sum tests, as appropriate. Multivariable logistic regression models were used to adjust for potential confounders.

RESULTS

Of the 3,703 low-risk multiparous women meeting inclusion criteria, 453 (12%) delivered between 39 0/7 and 39 4/7 after an elective induction of labor. Women who underwent elective induction of labor were more likely to be privately insured, non-Hispanic, and weigh more at their first prenatal visit (all P<.01) compared with expectant management. An elective induction of labor was associated with decreased frequency of the perinatal composite morbidity (4.0% vs 7.1%; adjusted odds ratio [aOR] 0.57, 95% CI 0.34-0.96) compared with expectant management. Fewer cesarean deliveries occurred among women in the elective induction of labor group (5.1% vs 6.6%; aOR 0.60, 95% CI 0.37-0.97). Other maternal outcomes (hypertensive disorders, chorioamnionitis, and operative vaginal deliveries) as well as neonatal intensive care unit admissions were not different between groups.

CONCLUSION

Elective induction of labor in low-risk multiparous women in the 39th week of gestation was associated with decreased perinatal morbidity and a lower frequency of cesarean delivery compared with expectant management.

Elective induction of labor: friend or foe?

Elective induction of labor is defined as labor induction in the absence of a clear medical indication. Whether elective labor induction at 39 weeks is a reasonable option for obstetric practice has been a hotly debated topic for decades. Historically, labor induction in low-risk nulliparous women has been discouraged due to the belief that this intervention increases the risk for cesarean delivery without a clear benefit. This review discusses the observational and randomized data that have informed this debate, focusing on recent studies that have reshaped how we think about elective labor induction at 39 weeks of gestation.

Patients' perspectives regarding induction of labor in the absence of maternal and fetal indications: are our patients ready for the ARRIVE trial?

BACKGROUND

After careful review of the ARRIVE trial (A Randomized Trial of Induction Versus Expectant Management) data, induction of labor prior to one's due date in the absence of maternal and fetal indications (which the American College of Obstetricians and Gynecologists currently refers to as "elective") is now endorsed as a "reasonable" option by the American College of Obstetricians and Gynecologists (ACOG). As a result, there has been much discussion among providers regarding how best to operationalize this ACOG recommendation into shared decision making regarding delivery planning. However, we lack a formal understanding of the perspectives of patients themselves on this topic.

OBJECTIVE

To assess patient understanding and preference for induction of labor prior to one's due date.

MATERIALS AND METHODS

We conducted an anonymous, cross-sectional survey of women in their third trimester of pregnancy presenting for routine obstetric care in August 2018. The survey included a series of questions designed to assess basic demographics, obstetric history, and patient understanding and opinions about the practice of induction of labor, with a focus on induction of labor prior to one's due date in the absence of maternal and fetal indications.

RESULTS

A total of 108 women were approached for participation, and 100 women participated in this survey (93% participation). Of the participants, 99% were supportive of induction of labor for fetal indications, and 96% were supportive for maternal indications prior to one's due date. In contrast, 54% of participants were not interested in induction of labor in the absence of maternal and fetal indications prior to one's due date. Women opposed to induction of labor in the absence of maternal and fetal indications were almost 4 times more likely to be concerned about the possibility that induction of labor in the absence of maternal and fetal indications could cause fetal harm (odds ratio, 3.9; confidence interval, 1.2-13.2).

CONCLUSION

Nearly all women surveyed in our pilot study were interested in induction of labor prior to one's due date for maternal or fetal indications. 46% of those surveyed were interested in induction of labor in the absence of maternal and fetal indications prior to their due date. Concern about potential fetal harm was more likely among women opposed to induction of labor in the absence of maternal and fetal indications. As providers discuss delivery planning with their patients, these results may provide a useful context for operationalizing and individualizing the results of the ARRIVE trial for their patients.

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.

Elective induction of labor at 39 weeks compared with expectant management: a meta-analysis of cohort studies

BACKGROUND

Elective induction of labor at 39 weeks among low-risk nulliparous women has reduced the chance of cesarean and other adverse maternal and perinatal outcomes in a randomized trial, although its clinical effectiveness in nonresearch settings remains uncertain.

OBJECTIVE

To perform a systematic review of observational studies that compared elective induction of labor at 39 weeks among nulliparous women with expectant management and to use meta-analytic techniques to estimate the association of elective induction with cesarean delivery, as well as other maternal and perinatal outcomes.

STUDY DESIGN

Studies were eligible for this meta-analysis only if they: (1) were observational; (2) compared women undergoing labor induction at 39 weeks with women undergoing expectant management beyond that gestational age; (3) included women in the induction group only if they had no other indication for labor induction at 39 weeks; and (4) provided data specifically for nulliparous women. The predefined primary outcome was cesarean delivery, and secondary outcomes representing other maternal and perinatal morbidities also were evaluated. Outcome data from different studies were combined to estimate pooled relative risks with 95% confidence intervals using random-effects models.

RESULTS

Of 375 studies identified by the initial search, 6 cohort studies, which included 66,019 women undergoing elective labor induction at 39 weeks and 584,390 undergoing expectant management, met inclusion criteria. Elective induction of labor at 39 weeks was associated with a significantly lower frequency of cesarean delivery (26.4% vs 29.1%; relative risk, 0.83; 95% confidence interval, 0.74-0.93), as well as of peripartum infection (2.8% vs 5.2%; relative risk, 0.53; 95% confidence interval, 0.39-0.72). Neonates of women in the induction group were less likely to have respiratory morbidity (0.7% vs 1.5%; relative risk, 0.71; 95% confidence interval, 0.59-0.85); meconium aspiration syndrome (0.7% vs 3.0%; relative risk, 0.49; 95% confidence interval, 0.26-0.92); and neonatal intensive care unit admission (3.5% vs 5.5%; relative risk, 0.80; 95% confidence interval, 0.72-0.88). There also was a lower risk of perinatal mortality (0.04% vs 0.2%; relative risk, 0.27; 95% confidence interval, 0.09-0.76).

CONCLUSION

This meta-analysis of 6 cohort studies demonstrates that elective induction of labor at 39 weeks, compared with expectant management beyond that gestational age, was associated with a significantly lower risk of cesarean delivery, maternal peripartum infection, and perinatal adverse outcomes, including respiratory morbidity, intensive care unit admission, and mortality.

The risk of intrapartum/neonatal mortality and morbidity following birth at 37 weeks of gestation: a nationwide cohort study

Objective

To assess intrapartum/neonatal mortality and morbidity risk in infants born at 37 weeks of gestation compared with infants born at 39–41 weeks of gestation.

Design

Nationwide cohort study.

Setting

The Netherlands.

Population

A total of 755 198 women delivering at term of a singleton without congenital malformations during 2010–14.

Methods

We used data from the national perinatal registry (PERINED). Analysis was performed with logistic regression and stratification for the way labour started and type of care.

Main outcome measures

Intrapartum or neonatal mortality up to 28 days and adverse neonatal outcome (neonatal mortality, 5‐minute Apgar <7, and/or neonatal intensive care unit admission).

Results

At 37 weeks of gestation intrapartum/neonatal mortality was 1.10‰ compared with 0.59‰ at 39–41 weeks (P < 0.0001). Adjusted odds ratio (aOR) for 37 weeks compared with 39–41 weeks was 1.84 (95% CI) 1.39–2.44). Adverse neonatal outcome at 37 weeks was 21.4‰ compared with 12.04‰ at 39–41 weeks (P < 0.0001) with an aOR 1.63 (95% CI 1.53–1.74). Spontaneous start of labour at 37 weeks of gestation was significantly associated with increased intrapartum/neonatal mortality with an aOR of 2.20 (95% CI 1.56–3.10), in both primary (midwifery‐led) care and specialist care. Neither induction of labour nor planned caesarean section showed increased intrapartum/neonatal mortality risk.

Conclusions

Birth at 37 weeks of gestation is independently associated with a higher frequency of clinically relevant adverse perinatal outcomes than birth at 39–41 weeks. In particular, spontaneous start of labour at 37 weeks of gestation doubles the risk for intrapartum/neonatal mortality. Extra fetal monitoring is warranted.

Tweetable abstract

Birth at 37 weeks of gestation gives markedly higher intrapartum/neonatal mortality risk than at 39–41 weeks, especially with spontaneous start of labour.

Tweetable abstract

Birth at 37 weeks of gestation gives markedly higher intrapartum/neonatal mortality risk than at 39–41 weeks, especially with spontaneous start of labour.

Maternal and newborn outcomes with elective induction of labor at term

BACKGROUND

A growing body of evidence supports improved or not worsened birth outcomes with nonmedically indicated induction of labor at 39 weeks gestation compared with expectant management. This evidence includes 2 recent randomized control trials. However, concern has been raised as to whether these studies are applicable to a broader US pregnant population.

OBJECTIVE

Our goal was to compare outcomes for electively induced births at ≥39 weeks gestation with those that were not electively induced.

STUDY DESIGN

We conducted a retrospective cohort study using chart-abstracted data on births from January 1, 2012, to December 31, 2017, at 21 hospitals in the Northwest United States. The study was restricted to singleton cephalic hospital births at 39⁺⁰-42⁺⁶ weeks gestation. Exclusions included previous cesarean birth, missing data for delivery type or gestational week at birth, antepartum stillbirth, cesarean birth without any attempt at vaginal birth, fetal anomaly, gestational diabetes mellitus, prepregnancy diabetes mellitus, and prepregnancy hypertension. The rate of cesarean birth for elective inductions at both 39 and 40 weeks gestation was compared with the rate in all other on-going pregnancies in the same gestational week. Maternal outcomes (operative vaginal birth, shoulder dystocia, 3^rd- or 4^th-degree perineal laceration, pregnancy-related hypertension, and postpartum hemorrhage) and newborn infant outcomes (macrosomia, 5-minute Apgar <7, resuscitation at delivery, intubation, respiratory complications, and neonatal intensive care unit admission) were also compared between elective inductions and on-going pregnancies at 39 and 40 weeks gestation. Logistic regression modeling was used to produce odds ratios for outcomes with adjustment for maternal age and body mass index. Results were stratified by parity and gestational week at birth. Duration of hospital stay (admission to delivery, delivery to discharge, and total stay) were compared between elective inductions and on-going pregnancies.

RESULTS

A total of 55,694 births were included in the study cohort: 4002 elective inductions at ≥39⁺⁰ weeks gestation and 51,692 births at 39⁺⁰-42⁺⁶ weeks gestation that were not electively induced. In nulliparous women, elective induction at 39 weeks gestation was associated with a decreased likelihood of cesarean birth (14.7% vs 23.2%; adjusted odds ratio, 0.61; 95% confidence interval, 0.41-0.89) and an increased rate of operative vaginal birth (18.5% vs 10.8%; adjusted odds ratio, 1.8; 95% confidence interval, 1.28-2.54) compared with on-going pregnancies. In multiparous women, cesarean birth rates were similar in the elective inductions and on-going pregnancies. Elective induction at 39 weeks gestation was associated with a decreased likelihood of pregnancy-related hypertension in nulliparous (2.2% vs 7.3%; adjusted odds ratio, 0.28; 95% confidence interval, 0.11-0.68) and multiparous women (0.9% vs 3.5%; adjusted odds ratio, 0.24; 95% confidence interval, 0.15-0.38). Term elective induction was not associated with any statistically significant increase in adverse newborn infant outcomes. Elective induction of labor at 39 weeks gestation was associated with increased time from admission to delivery for both nulliparous (1.3 hours; 95% confidence interval, 0.2-2.3) and multiparous women (3.4 hours; 95% confidence interval, 3.2-3.6).

CONCLUSION

Elective induction of labor at 39 weeks gestation is associated with a decrease in cesarean birth in nulliparous women, decreased pregnancy-related hypertension in multiparous and nulliparous women, and increased time in labor and delivery. How to use this information remains the challenge.

Pregnancy outcomes of elective induction in low-risk term pregnancies: A propensity-score analysis

We investigated the mode of delivery and perinatal outcomes in low-risk pregnant women whose labor was electively induced or expectantly managed at term.Healthy women with viable, vertex singleton pregnancies at 37 to 40 weeks of gestation were included. Women electively induced (n = 416) in each week (37-37, 38-38, 39-39, 40-40 weeks) were compared with pregnant women with spontaneous labor (n = 487). The primary outcome was mode of delivery. A propensity score (PS) was derived using logistic regression to model the probability of elective induction group as a function of potential confounders. Altogether, 284 women with elective induction were matched with 284 women who underwent expectant management to create a PS-matched population. All analysis was performed using SAS software, version 9.4 (SAS Institute Inc., Cary, NC). All P values reported of the significance level was set at <.05.There are no significant differences of delivery mode, neonatal intensive care unit (NICU) admission, and neonatal complication between PS-matched groups. Incidence of antepartum complications showed higher in the elective induction group compared to the spontaneous labor group (P = .04). When comparing each gestational week, incidence of NICU admission at 38 weeks in the elective induction group [10/74 (13.5%)] was significantly higher than in and the spontaneous labor group [2/74 (2.7%)] (P = .04).Elective induction of labor at term is not associated with increased risk of cesarean delivery. However, overall incidence of NICU admission at 38 gestational weeks seems to be increased in elective induction.

The Possible Role of Placental Morphometry in the Detection of Fetal Growth Restriction

Fetal growth restriction (FGR) is often the result of placental insufficiency and is characterized by insufficient transplacental transport of nutrients and oxygen. The main underlying entities of placental insufficiency, the pathophysiologic mechanism, can broadly be divided into impairments in blood flow and exchange capacity over the syncytiovascular membranes of the fetal placenta villi. Fetal growth restriction is not synonymous with small for gestational age and techniques to distinguish between both are needed. Placental insufficiency has significant associations with adverse pregnancy outcomes (perinatal mortality and morbidity). Even in apparently healthy survivors, altered fetal programming may lead to long-term neurodevelopmental and metabolic effects. Although the concept of fetal growth restriction is well appreciated in contemporary obstetrics, the appropriate detection of FGR remains an issue in clinical practice. Several approaches have aimed to improve detection, e.g., uniform definition of FGR, use of Doppler ultrasound profiles and use of growth trajectories by ultrasound fetal biometry. However, the role of placental morphometry (placental dimensions/shape and weight) deserves further exploration. This review article covers the clinical relevance of placental morphometry during pregnancy and at birth to help recognize fetuses who are growth restricted. The assessment has wide intra- and interindividual variability with various consequences. Previous studies have shown that a small placental surface area and low placental weight are associated with a slower growth of the fetus. Parameters such as placental surface area, placental volume and placental weight in relation to birth weight can help to identify FGR. In the future, a model including sophisticated antenatal placental morphometry may prove to be a clinically useful method for screening or diagnosing growth restricted fetuses, in order to provide optimal monitoring.

Gestational Diabetes: Underpinning Principles, Surveillance, and Management

Gestational diabetes mellitus (GDM) is carbohydrate intolerance resulting in hyperglycemia with onset during pregnancy. The article aims to provide clinicians with a working framework to minimize maternal and neonatal morbidity. Landmark historical and recent data are reviewed and presented to provide clinicians with a quick, easy reference for recognition and management of GDM. Data presented tie in insights with underlying pathophysiologic processes leading to GDM. Screening and diagnostic thresholds are discussed along with management upon diagnosis. Good clinical practice regarding screening, diagnosis, and management of GDM effectively reduces risk and improves outcomes of women and fetuses in affected pregnancies.

A comparative study of three different forecasting methods for trial of labor after cesarean section

AIM

This study aims to establish a convenient and practical predelivery scoring system for trial of labor after cesarean section (TOLAC).

METHODS

The data of 498 patients undergoing TOLAC were retrospectively studied. Indices with statistically significant differences, including cervical score, fetal weight, fetal pelvic index, body mass index and age, were selected. Combined with the presence of vaginal delivery history and indications of the previous cesarean section in these patients, three prenatal forecast scales for vaginal birth after cesarean (VBAC) were established. The receiver operating characteristic curve was drawn, and the best cut-off point was determined. Then, the areas under the curve of the three forecasting methods were compared. The scoring method with the largest area under the curve was considered the best method.

RESULTS

The six indications of cesarean section used for the forecasting scale were as follows: cervical score, fetal weight, body mass index, age, presence of vaginal delivery history and the presence of previous obstructive dystocia. The scale that had the largest area under the curve was considered the best forecasting scale.

CONCLUSION

The prenatal forecasting method for TOLAC was preliminarily investigated. It was determined that the scale with six indicators, such as the cervical score, could be used for the prenatal evaluation of TOLAC, providing a predictive basis for the possible success of the trial production for pregnant women. The method and process of VBAC section in our hospital was safe and effective.

Labor Induction versus Expectant Management in Low-Risk Nulliparous Women

BACKGROUND

The perinatal and maternal consequences of induction of labor at 39 weeks among low-risk nulliparous women are uncertain.

METHODS

In this multicenter trial, we randomly assigned low-risk nulliparous women who were at 38 weeks 0 days to 38 weeks 6 days of gestation to labor induction at 39 weeks 0 days to 39 weeks 4 days or to expectant management. The primary outcome was a composite of perinatal death or severe neonatal complications; the principal secondary outcome was cesarean delivery.

RESULTS

A total of 3062 women were assigned to labor induction, and 3044 were assigned to expectant management. The primary outcome occurred in 4.3% of neonates in the induction group and in 5.4% in the expectant-management group (relative risk, 0.80; 95% confidence interval [CI], 0.64 to 1.00). The frequency of cesarean delivery was significantly lower in the induction group than in the expectant-management group (18.6% vs. 22.2%; relative risk, 0.84; 95% CI, 0.76 to 0.93).

CONCLUSIONS

Induction of labor at 39 weeks in low-risk nulliparous women did not result in a significantly lower frequency of a composite adverse perinatal outcome, but it did result in a significantly lower frequency of cesarean delivery. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ARRIVE ClinicalTrials.gov number, NCT01990612 .).

Elective Induction of Labor: What is the Impact?

Elective induction of labor (ie, without a maternal or fetal indication) is common in the United States. When using the correct comparison group (elective induction vs expectant management) induction is not associated with an increased risk of cesarean delivery. Moreover, elective induction after 39 weeks seems to have maternal benefits (eg, lower infection rates) as well as a reduction in neonatal morbidity and the potential for a decrease in term stillbirth. However, these risks, especially stillbirth, are low in a healthy cohort and there are potential negative impacts on maternal satisfaction, breastfeeding, and cost/resource use that must be considered.

Elective induction of labor at 39 weeks among nulliparous women: The impact on maternal and neonatal risk

Objective

Optimal management of pregnancies at 39 weeks gestational age is unknown. Therefore, we sought to perform a comparative effectiveness analysis of elective induction of labor (eIOL) at 39 weeks among nulliparous women with non-anomalous singleton, vertex fetuses as compared to expectant management (EM) which included IOL for medical or obstetric indications or at 41 weeks in undelivered mothers.

Materials and methods

A Monte Carlo micro-simulation model was constructed modeling two mutually exclusive health states: eIOL at 39 weeks, or EM with IOL for standard medical or obstetrical indications or at 41 weeks if undelivered. Health state distribution probabilities included maternal and perinatal outcomes and were informed by a review of the literature and data derived from the Consortium of Safe Labor. Analyses investigating preferences for maternal versus infant health were performed using weighted utilities. Primary outcome was determining which management strategy posed less maternal and neonatal risk. Secondary outcomes were rates of cesarean deliveries, maternal morbidity and mortality, stillbirth, neonatal morbidity and mortality, and preferences regarding the importance of maternal and perinatal health.

Results

A management strategy of eIOL at 39 weeks resulted in less maternal and neonatal risk as compared to EM with IOL at 41 weeks among undelivered patients. Cesarean section rates were higher in the EM arm (35.9% versus 13.9%, p<0.01). When analysis was performed only on patients with an unfavorable cervix, 39 week eIOL still resulted in fewer cesarean deliveries as compared to EM (8.0% versus 26.1%, p<0.01). There was no statistical difference in maternal mortality (eIOL 0% versus EM 0.01%, p = 0.32) but there was an increase in maternal morbidity among the EM arm (21.2% versus 16.5, p<0.01). There were more stillbirths (0.13% versus 0%, p<0.0003), neonatal deaths (0.25% versus 0.12%, p< 0.03), and neonatal morbidity (12.1% versus 9.4%, p<0.01) in the EM arm as compared to the eIOL arm. Preference modeling revealed that 39 week eIOL was favored over EM.

Conclusions and relevance

Mathematical modeling revealed that eIOL at 39 weeks resulted in lower population risks as compared to EM with induction of labor at 41 weeks. Specifically, eIOL at 39 weeks resulted in a lower cesarean section rate, lower rates of maternal morbidity, fewer stillbirths and neonatal deaths, and lower rates of neonatal morbidity.

National Partnership for Maternal Safety: Consensus Bundle on Safe Reduction of Primary Cesarean Births-Supporting Intended Vaginal Births

Cesarean births and associated morbidity and mortality have reached near epidemic proportions. The National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care responded by developing a patient safety bundle to reduce the number of primary cesarean births. Safety bundles outline critical practices to implement in every maternity unit. This National Partnership for Maternity Safety bundle, as with other bundles, is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and Systems Learning. Bundle components may be adapted to individual facilities, but standardization within an institution is advised. Evidence-based resources and recommendations are provided to assist implementation.

National Partnership for Maternal Safety: Consensus Bundle on Safe Reduction of Primary Cesarean Births- Supporting Intended Vaginal Births

Cesarean births and associated morbidity and mortality have reached near epidemic proportions. The National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care responded by developing a patient safety bundle to reduce the number of primary cesarean births. Safety bundles outline critical practices to implement in every maternity unit. This National Partnership for Maternity Safety bundle, as with other bundles, is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and Systems Learning. Bundle components may be adapted to individual facilities, but standardization within an institution is advised. Evidence-based resources and recommendations are provided to assist implementation.

Nonmedically indicated induction in morbidly obese women is not associated with an increased risk of cesarean delivery

BACKGROUND

The prevalence of morbid obesity (body mass index ≥40 kg/m²) in women aged 20-39 years was 7.5% in 2009 through 2010. Morbid obesity is associated with an increased risk of stillbirth compared with normal body mass index, especially >39 weeks' gestation. The data regarding increased risk of cesarean delivery associated with nonmedically indicated induction of labor compared to expectant management in morbidly obese women are limited.

OBJECTIVE

We sought to compare the cesarean delivery rate of nonmedically indicated induction of labor with expectant management in morbidly obese women without other comorbidity.

STUDY DESIGN

This was a retrospective cohort study from the Consortium on Safe Labor of morbidly obese women with singleton, cephalic gestations without previous cesarean, chronic hypertension, or gestational or pregestational diabetes between 37 0/7 and 41 6/7 weeks' gestation. We examined maternal outcomes including cesarean delivery, operative delivery, third- or fourth-degree laceration, postpartum hemorrhage, and composite maternal outcome (any of: transfusion, intensive care unit admission, venous thromboembolism). We also examined neonatal outcomes including shoulder dystocia, macrosomia (>4000 g), neonatal intensive care unit admission, and composite neonatal outcome (5-min Apgar score <5, stillbirth, neonatal death, or asphyxia or hypoxic-ischemic encephalopathy). Adjusted odds ratios with 95% confidence intervals were calculated, controlling for maternal characteristics, hospital type, and simplified Bishop score. Analyses were conducted at early and full term (37 0/7 to 38 6/7 and 39 0/7 to 40 6/7 weeks' gestation, respectively). Women who delivered between 41 0/7 and 41 6/7 weeks' gestation were included as expectant management group.

RESULTS

Of 1894 nulliparous and 2455 multiparous morbidly obese women, 429 (22.7%) and 791 (32.2%) had nonmedically indicated induction, respectively. In nulliparas, nonmedically indicated induction was not associated with increased risks of cesarean delivery and was associated with decreased risks of macrosomia (2.2% vs 11.0%; adjusted odds ratio, 0.24; 95% confidence interval, 0.05-0.70) at early term and decreased neonatal intensive care unit admission (5.1% vs 8.9%; adjusted odds ratio, 0.59; 95% confidence interval, 0.33-0.98) at full term compared with expectant management. In multiparas, nonmedically indicated induction compared with expectant management was associated with a decreased risk of macrosomia at early term (4.2% vs 14.3%; adjusted odds ratio, 0.30; 95% confidence interval, 0.13-0.60), cesarean delivery at full term (5.4% vs 7.9%; adjusted odds ratio, 0.64; 95% confidence interval, 0.41-0.98), and composite neonatal outcome (0% vs 0.6%; adjusted odds ratio, 0.10; 95% confidence interval, <.01-0.89) at full term.

CONCLUSION

In morbidly obese women without other comorbidity, nonmedically indicated induction was not associated with an increased risk of cesarean delivery.

Perinatal legislative policies and health outcomes

Perinatal epidemiology examines the variation and determinants of pregnancy outcomes from a maternal and neonatal perspective. However, improving public and population health also requires the translation of this evidence base into substantive public policies. Assessing the impact of such public policies requires sufficient data to include potential confounding factors in the analysis, such as coexisting medical conditions and socioeconomic status, and appropriate statistical and epidemiological techniques. This review will explore policies addressing three areas of perinatal medicine-elective deliveries prior to 39 weeks' gestation; perinatal regionalization; and mandatory paid maternity leave policies-to illustrate the challenges when assessing the impact of specific policies at the patient and population level. Data support the use of these policies to improve perinatal health, but with weaker and less certain effect sizes when compared to the initial patient-level studies. Improved data collection and epidemiological techniques will allow for improved assessment of these policies and the identification of potential areas of improvement when translating patient-level studies into public policies.

Term elective induction of labour and perinatal outcomes in obese women: retrospective cohort study

OBJECTIVE

To compare perinatal outcomes between elective induction of labour (eIOL) and expectant management in obese women.

DESIGN

Retrospective cohort study.

SETTING

Deliveries in California in 2007.

POPULATION

Term, singleton, vertex, nonanomalous deliveries among obese women (n = 74 725).

METHODS

Women who underwent eIOL at 37 weeks were compared with women who were expectantly managed at that gestational age. Similar comparisons were made at 38, 39, and 40 weeks. Results were stratified by parity. Chi-square tests and multivariable logistic regression were used for statistical comparison.

MAIN OUTCOME MEASURES

Method of delivery, severe perineal lacerations, postpartum haemorrhage, chorioamnionitis, macrosomia, shoulder dystocia, brachial plexus injury, respiratory distress syndrome.

RESULTS

The odds of caesarean delivery were lower among nulliparous women with eIOL at 37 weeks [odds ratio (OR) 0.55, 95% confidence interval (CI) 0.34-0.90] and 39 weeks (OR 0.77, 95% CI 0.63-0.95) compared to expectant management. Among multiparous women with a prior vaginal delivery, eIOL at 37 (OR 0.39, 95% CI 0.24-0.64), 38 (OR 0.65, 95% CI 0.51-0.82), and 39 weeks (OR 0.67, 95% CI 0.56-0.81) was associated with lower odds of caesarean. Additionally, eIOL at 38, 39, and 40 weeks was associated with lower odds of macrosomia. There were no differences in the odds of operative vaginal delivery, lacerations, brachial plexus injury or respiratory distress syndrome.

CONCLUSIONS

In obese women, term eIOL may decrease the risk of caesarean delivery, particularly in multiparas, without increasing the risks of other adverse outcomes when compared with expectant management.

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.

A risk of waiting: the weekly incidence of hypertensive disorders and associated maternal and neonatal morbidity in low-risk term pregnancies

BACKGROUND

Elective induction of labor (eIOL) prior to 39 weeks' gestation is discouraged because of presumed fetal benefits. However, few data exist on the maternal risks of expectant management. To date, no study has evaluated the maternal risk of developing a hypertensive disorder of pregnancy with expectant management of a low-risk gravid at term.

OBJECTIVE

We sought to evaluate the development of hypertensive disorders in term low-risk expectantly managed patients.

STUDY DESIGN

This is a retrospective cross-sectional study from 19 US hospitals, from 2002 to 2008 (Safe Labor Consortium) including all nonanomalous, cephalic, singleton pregnancies at 37-41 weeks. Women with a history of hypertension, diabetes mellitus, cardiovascular disease, or planned cesarean delivery or from centers with incomplete hypertensive data were excluded. Women with eIOL in each week were compared with women managed expectantly until the next week of gestation or beyond. The primary outcome was the frequency of hypertensive complications.

RESULTS

Of 114,651 low-risk deliveries, 12,772 (11.1%) had eIOL. The cohort was 49.2% nulliparous, 51.1% white, and obese (mean body mass index 30.2 kg/m(2)). The risk of developing any hypertension in expectantly managed women was 4.1% after 37 weeks, 3.5% after 38 weeks, 3.2% after 39 weeks, and 2.6% after 40 weeks. Compared with eIOL, women with hypertensive disorders had significantly higher rates of cesarean delivery and maternal morbidities (intensive care unit admission or death, third- or fourth-degree lacerations, maternal infections, and bleeding complications) at each week of gestation and the composite neonatal morbidity at 38 and 39 weeks of gestation.

CONCLUSION

For women at low risk expectantly managed at term, there is a risk of developing hypertensive complications for each additional week of pregnancy, with associated increases in maternal and neonatal morbidities.

A comparison of obstetrical outcomes and costs between misoprostol and dinoprostone for induction of labor

OBJECTIVE

The objective of this study is to compare resource utilization (efficiency) and obstetrical/cost outcomes of single dose misoprostol versus dinoprostone for induction of labor (IOL) at term.

METHODS

Retrospective cohort of induced deliveries 37-41 weeks gestation presenting with a Bishop score ≤4 using single-dose-50 mcg vaginal misoprostol or 10 mg-dinoprostone vaginal-inserts. Dinoprostone patients were compared (5:1) with misoprostol patients. The primary outcome variable was length of L&D stay (proxy for resource utilization). Baseline characteristics, clinical outcomes, and costs were compared.

RESULTS

Three-hundred thirty-one patients were included, 276 received dinoprostone and 55 received misoprostol. The misoprostol group had statistically significant decreased time to active labor [median 8 h (1.6,24) versus 12(0.8,52)], time-to-delivery [median 11 h (4,31) versus 17(2.8,56)] and L&D stay [median 16 h (13,28) versus 24(18,30)]. Differences remained significant after adjustment for race, method of delivery, birth weight, gravidity/parity, gestational age, and BMI (adjusted p values <0.001,  <0.01, and < 0.05, respectively). There were no statistical differences in Apgar scores, tachysystole rate, cesarean section rate, and composite maternal/neonatal morbidity. A policy of using misoprostol would result in annual cost savings of approximately $242 500 at our institution as compared with dinoprostone.

CONCLUSION

Single-dose misoprostol is more efficient in IOL at term with respect to L&D utilization and cost and its use is not associated with increased adverse obstetrical outcomes.