Factors associated with intrapartum cesarean section in women aged 40 years or older: a single-center experience in Japan

Objective: To elucidate the efficacy and safety of attempting a vaginal birth and to understand the factors that contribute to the increased risk of operative delivery in women aged 40 years or older.Methods: A database of the Japanese Red Cross Nagoya Daiichi Hospital was reviewed to identify women aged 40 years or older with singleton, vertex, and vital pregnancies who attempted vaginal delivery at and after 37 + 0 gestational weeks between January 2011 and December 2016.Results: A total of 415 women met the criteria for inclusion in this study, including 372 and 43 women who gave birth by vaginal delivery and by intrapartum cesarean section (CS), respectively. Vaginal delivery was observed in 84.1% (201/239) and 97.2% (171/176) of nulliparous and multiparous women, respectively. In a logistic regression model, nulliparity [odds ratio (OR), 5.18; 95% confidence interval (CI), 1.91-14.00], assisted reproductive technology (OR, 2.83; 95% CI, 1.42-5.62), and admission for induction of childbirth (OR, 2.68; 95% CI, 1.08-6.67) were associated with a higher likelihood of intrapartum CS. Of 372 women who delivered vaginally, 62 women needed operative delivery. Operative delivery was necessary for 25.4% (51/201) and 6.4% (11/171) of nulliparous and multiparous women, respectively. A logistic regression model identified nulliparity (OR, 3.91; 95% CI, 1.89-8.08) and administration of ecbolic (OR, 2.49; 95% CI, 1.21-5.10) as being independent factors associated with vacuum extraction.Conclusions: Maternal age 40 years or older should not be a barrier for attempting a vaginal delivery, and those women should be encouraged to attempt a vaginal delivery.