Outcomes among nulliparous women undergoing non-medically indicated induction of labor at 39 weeks compared to expectant management differ by maternal age

Objective: Previous literature have demonstrated the potential benefit of non-medically indicated induction of labor for nulliparous women at 39 weeks, 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 non-medically indicated induction of labor at 39 weeks as compared to expectant management vary based on maternal age. Methods: This was a retrospective cohort study of singleton, non-anomalous, term deliveries between 2007-2012 in California. We defined non-medically 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 to 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 employed for statistical comparisons and a p-value of less than 0.05 was used to indicate statistical significance. Results: A total of 677,727 women-infant dyads met our inclusion criteria and were included in this study. At 39 weeks’ gestation, 6% of women underwent non-medically indicated induction of labor and 94% underwent expectant management. Women 20-34 years old and ≥35 years old had lower odds of cesarean delivery if they underwent induction of labor. Women of all ages undergoing non-medically indicated induction of labor had higher adjusted odds ratios for operative vaginal delivery. Neonatal outcomes were better with non-medically indicated induction of labor, including lower odds of NICU admission and neonatal respiratory distress. Conclusion: Our study demonstrated that obstetric outcomes vary among women undergoing non-medically indicated induction of labor compared to expectant management when stratified by maternal age. These findings illustrate the importance of understanding age-related differences in outcomes associated with non-medically indicated induction of labor.