EP15.05: Fetal growth restriction between 18 and 24 weeks: outcomes and risk factors

To assess risk factors and associated outcomes with persistent fetal growth restriction (FGR) after mid-trimester diagnosis. Retrospective study of fetuses with FGR by estimated weight (EFW) < 10th percentile or abdominal circumference (AC) < 10th percentile identified between 18 – 24 weeks of gestation without structural or chromosomal anomalies. We compared pregnancies that had persistent FGR (at last scan prior to delivery) to those with resolved FGR. Primary outcome was small for gestational age (SGA) defined as birthweight < 10th percentile by WHO criteria. Secondary outcomes were preterm delivery < 37 weeks of gestation, stillbirth/neonatal death, and maternal outcomes. 398 singleton gestations were diagnosed with FGR between 18.0 – 24.0 weeks of gestation. After exclusion criteria, 161 patients (50.5%) were included for analysis; 69 (42.9%) had resolved FGR and 92 (57.1%) were persistent FGR. Maternal characteristics were similar between groups. Gestational age at diagnostic ultrasound were similar between groups (21 ± 1.4 weeks' gestation vs. 21 ± 1.4 weeks' gestation, p = 0.9). As compared to resolved FGR, pregnancies with persistent FGR were more likely to have: EFW ≤ 3% at initial diagnosis (62% persistent FGR vs. 26.1 resolved FGR%, p < 0.0001), have a trend towards abnormal Doppler studies (27% vs. 15.4% p = 0.17), more likely to be SGA at delivery (72.5% vs. 23.2%; p < 0.001), higher frequency of stillbirth/neonatal death (16.3% vs. 1.5%; p = .001), delivery prior 37 weeks of gestation (46.7% vs. 5.8% p < 0.0001), higher prevalence of maternal hypertensive disorders of pregnancy (41.3% vs. 20.2%; p = 0.006), and prolonged maternal hospital stay following delivery (3.6 ± 3.0 days vs. 2.5 ± 1.1 days; p = 0.004). Fetuses diagnosed with FGR at 18-24 weeks having an EFW ≤ 3rd percentile were likely to have persistent FGR. Those pregnancies for whom FGR persisted were more likely to be SGA at birth and have a higher frequency of fetal demise.