Maternal and perinatal outcomes in women >= 40 years undergoing induction of labor compared with women <35 years: Results from 4027 mothers

Aim Cesarean section is known to be increased with advanced maternal age in women undergoing induction of labor (IOL), but there is less information regarding other possible adverse maternal and fetal outcomes. Methods Retrospective cohort study of singleton, nulliparous, at-term women undergoing IOL between January 2007 and September 2020. Outcomes studied were: cesarean section, failed induction rate, fetal distress, post-partum hemorrhage, post-partum hysterectomy, and need of transfusion. Neonatal variables analyzed were: Apgar score, umbilical cord pH, need of admission to neonatal intensive care unit, and mortality. Results A total of 4027 women met the inclusion criteria; 1968 (48.9%) of mothers were <35 years, 1283 (31.9%) were 35-39 years, 658 (16.3%) were 40-44 years, and 118 (2.9%) were >= 45 years. Results showed a significantly increased incidence of c-section in women >= 35 years, with an OR 1.79 (95% CI 1.50-2.14) for women 40-44 years and OR 3.95 (95% CI 2.66-5.98) for women >= 45 years. The main indication for cesarean delivery was failed IOL, and this risk was also significantly increased in women >= 40 years. These differences remained significant after adjustment for confounding factors. No other adverse maternal or fetal outcomes showed an association with age. Conclusion Maternal age >= 40 years was associated with an increased risk of c-section after IOL at term compared with younger women, mainly because of failed induction, but no association with other adverse maternal or neonatal outcomes were found in our population. Risks and benefits of IOL in older women should be individually evaluated and adequately discussed with mothers.