243 Mid-second trimester estimated fetal weight >95th percentile and the association with large for gestational age

Abstract

To evaluate maternal and neonatal outcomes of low-risk singleton pregnancies with estimated fetal weight (EFW) > 95th% during routine mid-second trimester ultrasound (between 17 and 22 weeks and 6 days’ gestation). A retrospective cohort study of all women who underwent a routine fetal anatomy ultrasound between 17 and 22 weeks and 6 days’ gestation at an urban community-based hospital from January 2016 to May 2019 was performed. The primary outcome was large for gestational age neonate at term. Secondary outcomes were abnormal glucose testing, gestational diabetes, cesarean delivery, shoulder dystocia, and obstetric anal sphincter injuries. Descriptive statistics were computed to describe the study population. Continuous outcomes were compared between EFW >95th% and EFW=50th% groups utilizing Wilcoxon Rank Sum tests and categorical variables were compared using Fisher’s exact test or Chi-squared tests. A logistic regression analysis was performed to estimate these associations while adjusting for potential confounders. In total, 3,868 unique patient charts were identified. 49 (1.3%) had an EFW >95th % and 54 (1.4%) had an EFW=50th% and were eligible for review and subsequent analysis. When compared to EFW=50th%, the group with an EFW >95th% was more likely to have large for gestational age (LGA) newborns at term (41% vs. 4%, OR=18 95% CI 3.9-82). These findings were robust to adjustment for potential confounders (age, race, obesity, mode of delivery, etc.) in logistic regression modeling. There were no statistically significant differences amongst the two groups for the secondary outcomes. Estimated fetal weight >95th% at the time of routine ultrasound between 17 and 22 weeks and 6 days’ gestation is associated with large for gestational age neonates at term.There were no statistically significant findings for the secondary outcomes. Such gestations with EFW >95th% during the mid-second trimester may benefit from additional ultrasonography growth assessment at later gestational ages; however, early glucose tolerance testing does not appear indicated.