Analysis of Obstetric Outcomes by Hospital Location, Volume, and Teaching Status Associated With Non-Medically Indicated Induction of Labor at 39 Weeks.

Importance: Non-medically indicated induction of labor has been demonstrated to potentially improve some obstetric outcomes, such as decreasing cesarean birth. It has been reported that rates of cesarean birth and other obstetric outcomes vary among hospitals with different characteristics. Objective: To assess whether obstetric outcomes differ between nulliparous individuals with low-risk pregnancies managed with non-medically indicated induction of labor compared with expectant management in different types of hospitals. Design, Setting, and Participants: This retrospective cohort study included non-medically indicated induction of labor at 39 weeks' gestation compared with expectant management of singleton, nonanomalous, births in nulliparous women with low-risk pregnancies in California between January 1, 2007, and December 31, 2011. The initial analysis of these data was performed in 2021. Outcomes were assessed by 3 hospital characteristics: location (urban vs rural), obstetric volume, and teaching (academic vs community) status. Volume was categorized based on the average number of births per year and grouped into low (<1200 births per year), medium (1200-2399 births per year), and high (≥2400 births per year). Births with previous or planned cesarean delivery were excluded, and non-medically indicated induction of labor was defined as induction of labor without a specific medical indication. Testing with χ2 and multivariable logistic regression analyses was used for statistical comparisons with a cutoff level of P = .01. Exposure: Non-medically indicated induction of labor at 39 weeks' gestation. Main Outcomes and Measures: The primary outcome was cesarean birth, and numerous secondary perinatal outcomes were also assessed. Results: There were 455 044 births included in this study. When stratified by hospital variables, a number of sociodemographic characteristics were significantly different, such as race and ethnicity, age, body mass index, and insurance type. The adjusted odds ratios (aORs) of cesarean birth were significantly lower in all settings with induction of labor except for low-volume hospitals, in which there was no significant difference (aOR, 0.95; 95% CI, 0.82-1.09). Chorioamnionitis and postpartum hemorrhage were lower with induction of labor among nearly every hospital when stratified by hospital characteristics. Neonatal outcomes were improved in all settings with induction of labor compared with expectant management. Conclusions and Relevance: These findings suggest that non-medically indicated induction of labor may be associated with a lower rate of cesarean births and some maternal and neonatal adverse outcomes in a range of hospital settings.