OC14.06: Optimal management and timing of delivery in late fetal growth restriction at term using a risk stratification protocol

The aim of the study was to prospectively evaluate in over 1000 patients, a protocol for late fetal growth restriction (FGR) management classifying pregnancies at high or low risk of adverse perinatal outcome using ultrasound parameters. This was a prospective study of women with a non-anomalous singleton pregnancy from 32 weeks, at University College London Hospital, UK, between 2018 and 2022. Women were included if any of the following was present: estimated fetal weight (EFW) ≤10th centile (c.), abdominal circumference (AC) decrease ≥50 c. compared with a previous scan, umbilical artery (UmbA) Doppler pulsatility index (PI) >95th c. or cerebroplacental ratio (CPR) < 5th c. High-risk cases were delivered at 37-38 weeks if there EFW <10th c. plus any of the following: EFW<3rd c. or AC >50 c. drop, or UmbA PI >95th c. or CPR <5th c. Otherwise late FGR was considered as Low-risk and managed conservatively until 40-41 weeks. The primary outcome was a composite of severe adverse perinatal outcomes including any of the following: stillbirth, neonatal or infant death, advanced resuscitation, 5 min APGAR<7, UmbA pH<7, sepsis, cerebral, respiratory and circulatory morbidity. Multiple logistic regression analysis was performed. Sample size was powered to explore differences in severe adverse neonatal outcome. 408 and 594 of 1002 patients were classified as High- and Low-risk FGR respectively. Neonates from the High-risk group were twice as likely to have severe adverse perinatal outcomes [8.3 Vs 3.2%, aOR 2.1 (95% CI 1.2-3.9), P = 0.02]. There was no extended perinatal mortality in the Low-risk group. Our study demonstrated that appropriate risk stratification of late FGR allows pregnancies at low risk of adverse perinatal outcomes to be managed conservatively at term up to 40-41 weeks with improved perinatal outcomes compared with the High-risk group, and no increase in perinatal mortality.