1123 Midtrimester fetal growth restriction as predictor of small for gestational age and adverse obstetrical outcomes

Abstract

To assess whether fetal growth restriction (FGR), defined as estimated fetal weight (EFW) or abdominal circumference (AC) < 10th percentile, diagnosed on midtrimester anatomy scan is predictive of small for gestational age (SGA) and is associated with adverse obstetrical outcomes. This is a single center retrospective cohort study of women undergoing anatomy scan at 18-24 weeks gestation from 1/2017-12/2019. Women 18-45 years of age carrying non-anomalous singleton gestations with documented delivery outcomes were included. EFW percentile was calculated using Hadlock 85; AC percentile was calculated using Hadlock 84. Fetuses with FGR were matched with the next normal weight fetus (EFW and AC between the 10th and 90th percentiles) undergoing anatomy scan on the ultrasound schedule. The primary outcome was the rate of SGA. Secondary outcomes included the rates of abnormal genetic screening, gestational age at delivery, NICU admission, composite neonatal morbidity (hypoglycemia, hypothermia, respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, seizure, sepsis), and pregnancy related hypertensive disorders. 167 pregnancies were included in the final analysis. Fetuses with FGR were more likely to be SGA at delivery. This difference persisted across different definitions of FGR (Table 1). The sensitivity and specificity of midtrimester FGR for predicting SGA were 74.9% and 73.6%, respectively. Neonates in the FGR group were more likely to require NICU admission and to have an adverse neonatal composite outcome. Fetuses in the FGR group did not have higher rates of abnormal aneuploidy screening and were not delivered at an earlier gestational age (38.5 versus 39.0 weeks, p=0.21). Women in the FGR group were not at increased risk for pregnancy related hypertensive disorders (Table 2). Singleton fetuses with growth restriction on midtrimester anatomy scan are at increased risk of being SGA, requiring NICU admission, and experiencing adverse neonatal outcomes. However, over 48% of fetuses with midtrimester FGR achieve normal birth weight.View Large Image Figure ViewerDownload Hi-res image Download (PPT)