Quantifying the Risks and Benefits of Continuing Labor Induction: Data for Shared Decision-Making.

OBJECTIVE: This study aimed to quantify the relative maternal and fetal risks and benefits of continuing labor induction. STUDY DESIGN: This retrospective cohort study included nulliparous women with nonanomalous, singleton, vertex, term pregnancies undergoing labor induction with intact membranes at a tertiary-care academic hospital from January 2015 to April 2017. The primary outcome was mode of delivery. Secondary outcomes included hemorrhage, transfusion, infection, and composite neonatal morbidity. The data were analyzed using chi-square and Fisher's exact tests. Multivariable regression was used to control for potential confounders. RESULTS: A total of 955 patients met the inclusion criteria. The median induction duration was 32.3 hours (interquartile range: 20.4-41 hours) and the vaginal delivery rate was 70.5% (n = 673). The chance of vaginal delivery at 12, 24, 36, 48, 60, and ≥60 hours was 76, 83, 77, 74, 72, and 48%, respectively. After controlling for confounders, there was a 20% decrease in chance of vaginal delivery with induction ≥ 24 hours compared with induction < 24 hours. The adjusted relative risks of hemorrhage, transfusion, and infection with induction ≥ 24 hours compared with induction < 24 hours were 1.9, 2.2, and 2.7, respectively (95% confidence interval [CI] of 1.4-2.5, 1.1-3.9, and 1.8-4.0, respectively). The relative risk for these outcomes remained stable or decreased at each subsequent time point. The increasing risks of hemorrhage and infection were primarily among patients who underwent cesarean delivery. There was no association between induction duration and neonatal morbidity. CONCLUSION: In this cohort, the chance of vaginal delivery remained nearly 50% even when induction extended beyond 60 hours. Risks of hemorrhage and maternal infection rose modestly over time, but primarily in patients who underwent cesarean delivery. There was no difference in the risk of transfusion beyond 24 hours and no association between induction duration and neonatal morbidity. These findings may be useful when engaging patients in shared decision-making during labor induction.

Relationship between maternal age and labor induction duration and outcomes in nulliparous women.

OBJECTIVE: To determine the relationship between maternal age and labor induction duration among nulliparous women. METHODS: This retrospective cohort study included nulliparous women with non-anomalous, term, singleton pregnancies undergoing labor induction with intact membranes at a tertiary-care academic hospital from January 2015 to April 2017. Maternal age was stratified as follows: <25 years, 25-29 years, 30-34 years, 35-39 years, and ≥ 40 years. The primary outcome was induction duration, defined as the time the first induction agent was administered to time of birth. Secondary outcomes were cesarean delivery, cesarean indication, hemorrhage, blood transfusion, peripartum infection, composite neonatal morbidity, and induction duration among the subset of women who ultimately underwent cesarean. The data were analyzed using chi-squared and Fisher exact tests. Multivariable regression was used to adjust for maternal race/ethnicity, maternal body mass index, gestational age at start of induction, and induction indication. Hazard ratios were used to calculate induction duration among women who underwent cesarean delivery, stratified by age and adjusted by the same variables. RESULTS: Among the 955 patients included, the median induction duration was 32.3 h (interquartile range (IQR) 20.4-41.0 h). Women 40 years and older had a slight increase in induction duration (adjusted odds ratio (aOR) 1.03, 95% confidence interval (CI) 1.01-1.05) and a seven-fold increased risk of induction lasting 60 h or longer (adjusted relative risk (aRR) 7.3, CI 1.8-29.9) when compared to those under 25 years of age; otherwise, there was no association between maternal age and labor induction duration. There was no association between age and cesarean delivery, cesarean indication, hemorrhage, transfusion, peripartum infection, or adverse neonatal outcomes. Furthermore, there was no association between maternal age and induction duration even among women who ultimately underwent cesarean. CONCLUSION: We found no association between maternal age and induction duration for women under 40 years of age. For women 40 years of age and older, these was an increased risk of labor induction lasting 60 h or longer. Despite this, we found no association between maternal age and cesarean delivery or other adverse maternal or fetal outcomes.