Neonatal outcome by planned mode of delivery in women with a body mass index of 35 or more: a retrospective cohort study.

Abstract

To compare neonatal outcomes of women with a body mass index (BMI) of ≥35 kg/m² who underwent a trial of labour with those of women who underwent a planned primary caesarean section (CS). A retrospective cohort study of births between April 2012 and March 2014. A provincial database: Better Outcomes Registry & Network (BORN) Ontario, Canada. A cohort of 8752 women with a BMI of ≥35 kg/m² who had a singleton birth at 38-42 weeks of gestation. Neonatal outcomes were compared between women who underwent a trial of labour (with either a successful vaginal birth or intrapartum CS) and those who underwent a planned CS. A composite of any of the following outcomes: intrapartum neonatal death, neonatal intensive care unit admission, 5-minute Apgar score of <7 or umbilical artery pH of <7.1. During the study period, 8433 (96.4%) women had a trial of labour and 319 (3.6%) had a planned CS. Intrapartum CS was performed in 1644 (19.5%) cases. There was no association between planned mode of delivery and the primary outcome (aOR 0.80, 95% CI 0.59-1.07). The primary outcome was lower among women who had a successful trial of labour (aOR 0.67, 95% CI 0.50-0.91) and was higher among women who had a failed trial of labour (aOR 1.74, 95% CI 1.21-2.48), compared with women who underwent a planned CS. In women with a BMI of ≥35 kg/m² at a gestational age of 38-42 weeks, neonatal outcomes are comparable between planned vaginal delivery and planned CS, although a failed trial of labour is at risk of adverse neonatal outcome. Neonatal outcomes are not affected by planned mode of delivery in women who are obese, with a BMI of ≥35 kg/m² .