The Risk of Stillbirth at Term and Timing of Delivery in Obese Women [38D

Abstract

INTRODUCTION: Studies have shown that a high body mass index (BMI), expressed in kg/m2, is an independent risk factor for stillbirth. The purpose of this study was to determine an optimal time of delivery in obese women in order to decrease the risk of stillbirth in this population. METHODS: We conducted a retrospective population-based cohort study using the CDC's Period Linked Birth-Infant Death and Fetal Death data. The study population included all singleton, term births with a recorded pre-pregnancy BMI that occurred between 2014 and 2017, inclusively. The risk of stillbirths in each BMI class was estimated at each gestational week from 37 weeks and onwards. RESULTS: Of the 12,742,980 births in our cohort that met study criteria, 46.8% were to women with a normal BMI, 26.9% were to women who were classified as overweight, 14.5% were to women in obesity class I, 7.3% in obesity class II, and 4.8% in obesity class III. As compared to women at 41 weeks with a normal BMI, there was a higher risk of stillbirth in women of obesity class I at 39 weeks (OR 1.15 95% CI 1.00–1.31), at 38 weeks for obesity class II (OR 1.21 95% CI 1.04–1.41) and at 37 weeks for obesity class III (OR 1.30 95% CI 1.11–1.52). CONCLUSION: As compared to women with a normal BMI, there was a higher risk of stillbirth at term in women with each increase in BMI class. Consideration should be given to early induction among these women to reduce the risk of stillbirth.