EP08.43: Sonographic surveillance and neonatal outcomes among pregnancies with periviable fetal growth restriction

Fetal growth restriction (FGR) is associated with increased neonatal morbidity and mortality. The risk for neonatal morbidity and mortality is inversely related to gestational age (GA) at diagnosis, particularly when the diagnosis is made at < 28 weeks GA. This study aims to compare perinatal outcomes between fetuses with periviable FGR (pFGR) who did and did not undergo weekly sonographic surveillance. A retrospective cohort study was conducted at 2 tertiary care centres between 1/2017 and 6/2023. pFGR was defined as a singleton gestation with an estimated fetal weight (EFW) < 500g, a GA between 22 0/7 and 28 6/7 weeks GA, and an EFW measuring ≤ 10% and/or genetic abnormalities were excluded. The surveillance cohort initiated weekly Doppler surveillance while the growth cohort underwent serial growth assessment between 22-28 weeks GA. The co-primary outcome was neonatal survival to 28 days and survival to hospital discharge. Secondary outcomes included neonatal delivery outcomes and diagnoses. Student's t-test for independent samples and chi-square (or Fisher's exact test) were performed to compare quantitative and categorial variables, respectively. Of 224 gestations, 208 liveborn neonates were included for analysis with 35.6% in the screened cohort. The screened cohort had higher rates of abnormal Dopplers (46.9% v. 24.5%, p < 0.05) and NICU admissions (58.1% v. 21.6%, p < 0.05), delivered earlier (32.8 ± 5.5 weeks v. 36.5 ± 4.5 weeks, p < 0.05), and had lower birthweights (1755.7g ± 990.6 v. 2461.7g ± 703.7, p < 0.05). There was no difference in neonatal survival to 28 days or to hospital discharge. The surveillance cohort experienced higher rates of composite neonatal morbidity (60.8% v. 28.4%, p < 0.05). This observational cohort study suggests that concerning fetal status, as determined by Doppler findings, may have driven earlier delivery and increased morbidity in the surveillance cohort. There was no difference in neonatal survival between the groups.