Association of maternal Body Mass Index and parity on induced labor stages.

Abstract

Background: Obesity is a widespread pandemic and obstetric care must adapt to meet the needs of obese pregnant women. Little is known about the impact of Body Mass Index (BMI) on the induction of labor (IOL). Therefore, our objective was to evaluate if the duration of the first and second stages of IOL is affected by maternal BMI in nulliparous and multiparous women.

Methods: We included singleton pregnancies at term with cephalic presentation whose labor was induced from June 2018 to December 2019. Women were divided into two groups according to pre-pregnancy BMI in normal weight and obese women.

Results: A total of 668 women with IOL were included in the study, among them, 349 had a normal weight and 321 were obese. The first stage of labor was longer in obese multiparous than normal-weight women (normal weight 81.98±71.7 vs. obese 134.3±158.1 min, P=0.000), while the second stage resulted significantly shorter (normal weight 22.2±27.8 vs. obese 14.3±14.2 min, P=0.000). The total time elapsed from IOL beginning and delivery was significantly higher in obese nulliparous (normal weight 10.4±19.7 vs. obese 22.0±26.2 h, P=0.000). Operative vaginal deliveries, emergency cesarean section, and failed IOL resulted to be similar between the groups.

Conclusions: Obese multiparous women have longer first stages of labor while shorter second stages. The total time for induced obese nulliparous to reach delivery is higher than the normal weight. It might be reasonable to reconsider the partographs according to maternal BMI in case of induced labor for future obstetric practice.