Outcomes among Nulliparous Women Undergoing Nonmedically Indicated Induction of Labor at 39 Weeks Compared with Expectant Management Differ by Maternal Age

Abstract

Objective Prior studies have demonstrated the potential benefit of nonmedically indicated induction of labor for nulliparous women at 39 weeks of gestation, yet few have studied the impact of this management strategy in different maternal age groups on obstetric outcomes. We sought to assess whether obstetric outcomes among women undergoing nonmedically indicated induction of labor at 39 weeks of gestation as compared with expectant management vary based on maternal age. Study Design This was a retrospective cohort study of singleton, nonanomalous, deliveries between 2007 and 2012 in California. We defined nonmedically indicated induction of labor as induction of labor without a specific medical indication, and women with planned cesarean sections were excluded. We compared induction of labor with expectant management beyond the gestational age of induction and examined this comparison in different maternal age groups. Numerous maternal and neonatal outcomes were examined. Chi-squared and multivariable logistic regression analyses were used for statistical comparisons and a p-value of less than 0.05 was used to indicate statistical significance. Results A total of 630,485 women–infant dyads met our inclusion criteria and were included in this study. At 39 weeks' gestation, 6% of women underwent nonmedically indicated induction of labor and 94% underwent expectant management. Women 20 to 34 and ≥35 years old had lower odds of cesarean delivery if they underwent induction of labor. Women of all ages undergoing nonmedically indicated induction of labor had higher odds of operative vaginal delivery. Neonatal outcomes were better with nonmedically indicated induction of labor, including lower odds of neonatal intensive care unit admission and neonatal respiratory distress. Conclusion Our study demonstrated that obstetric outcomes vary among women undergoing nonmedically indicated induction of labor compared with expectant management when stratified by maternal age. These findings illustrate the importance of understanding age-related differences in outcomes associated with nonmedically indicated induction of labor. Key Points