OBJECTIVE: To investigate the prognostic value of maternal angiogenic factors in late-onset small fetuses, alone or in combination with the ultrasound and Doppler parameters currently used for the classification of low-risk small-for-gestational-age (SGA) fetuses or high-risk fetal growth restriction (FGR), overall and according to the presence or absence of pre-eclampsia. METHODS: This was a prospective cohort study of women with a singleton pregnancy with a diagnosis of late-onset fetal smallness (defined as birth weight <
10 RESULTS: Among the 602 included cases, 91 (15.1%) developed pre-eclampsia and 511 (84.9%) did not. In the overall study population, all parameters were associated independently with adverse perinatal outcome: EFW <
3 CONCLUSIONS: sFlt-1/PlGF ratio alone had a low predictive value for adverse perinatal outcome, but when combined with EFW, its predictive performance was similar to that of EFW combined with Doppler parameters. Combining sFlt-1/PlGF ratio with EFW and Doppler criteria achieved the highest DR for adverse perinatal outcome, and additionally, might help to identify imminent pre-eclampsia in pregnancies complicated by fetal smallness. These findings support the use of angiogenic factors as an additional criterion to those currently used for identifying high-risk FGR among late-onset small fetuses, but do not support their use as a standalone biomarker. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.