Sonographic Estimated Fetal Weight and Cesarean Delivery among Nulliparous Women with Obesity

Abstract

Objective This study was aimed to examine the association between having an ultrasound estimate of fetal weight (US-EFW) and mode of delivery among obese women. Study Design A retrospective cohort study of nulliparous women with a body mass index of ≥ 35 kg/m2 who delivered term singleton gestations. We examined whether having had an US-EFW within 35 days of delivery, or an US-EFW ≥ 90th percentile for gestational age, was associated with intrapartum cesarean delivery. Results Of 2,826 women, 22.5% (n = 636) had an US-EFW within 35 days of delivery. Having an US-EFW was associated with increased frequency of cesarean (43.1% for those with an US-EFW versus 30.0% for those without, p < 0.001); this finding persisted when controlling for confounders (adjusted odds ratio [aOR] 1.48, 95% confidence interval [CI] 1.21–1.81). Of the 636 women with an US-EFW, 22.5% (n = 143) had an US-EFW ≥ 90th percentile for gestational age, which was associated with increased frequency of an intrapartum cesarean (60.8% for those with an US-EFW ≥ 90th percentile vs. 37.9% for those with an US-EFW of < 90th percentile, p < 0.001), even when accounting for confounders (aOR = 1.78, 95% CI: 1.10–2.87). Conclusion The presence of an US-EFW among nulliparous obese women was associated with undergoing intrapartum cesarean delivery.