To analyze the value of the soluble fms‐like tyrosine kinase‐1/placental growth factor (sFlt‐1/PlGF) ratio in predicting the time to delivery in early‐onset fetal growth restriction (FGR) with preserved antegrade umbilical artery (UA) flow at diagnosis.

This was a prospective observational single‐center cohort study of pregnancies with early‐onset (< 32 + 0 weeks) FGR and antegrade UA flow, in which maternal serum sFlt‐1/PlGF ratio was determined at diagnosis. FGR was defined as estimated fetal weight < 3^rd centile or < 10^th centile with UA pulsatility index > 95^th centile, fetal middle cerebral artery pulsatility index < 5^th centile or cerebroplacental ratio < 5^th centile. The previously described sFlt‐1/PlGF ratio cut‐off value of 85 for facilitating the diagnosis of pre‐eclampsia was assessed in the prediction of the need to deliver in < 1 week and ≥ 4 weeks.

In total, 120 cases were included. There were 116 (96.7%) liveborn neonates and 108 (90.0%) perinatal survivors. Median (interquartile range (IQR)) gestational age at diagnosis of early‐onset FGR was 27.1 (25.7–29.4) weeks. Median (IQR) sFlt‐1/PlGF ratio at diagnosis was 196 (84–474). Ninety (75.0%) cases had a sFlt‐1/PlGF ratio ≥ 85. Among pregnancies with a liveborn neonate, median (IQR) interval to delivery in the groups with sFlt‐1/PlGF ratio < 85 and ≥ 85 was 41 (22–54) days and 11 (4–20) days, respectively (P < 0.01). The probability of having to deliver within 1 week after diagnosis was 0% and 35.6% in those with sFlt‐1/PlGF ratio < 85 and ≥ 85, respectively (P = 0.03), and the probability of delaying delivery for ≥ 4 weeks was 72.4% and 19.5%, respectively (P < 0.01).

sFlt‐1/PlGF ratio < 85 at diagnosis of early‐onset FGR with antegrade UA flow identifies a group of pregnancies in which the need to deliver within 1 week is very low and the interval to delivery is expected to be prolonged for ≥ 4 weeks in > 70% of cases. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.