EP17.09: Performance of sFlt1 ‐PlGF ratio at 35–36 weeks of gestation in nulliparous women in identifying SGA, pre‐eclampsia and FGR

To assess the performance of sFlt-1-PlGF ratio at 35-36 weeks' gestation in nulliparous women in identifying SGA, FGR and pre-eclampsia (overall and within 2 weeks). Prospective cohort sub-study within a large randomised trial (PE37), including women from the concealed arm of the study from a single centre between Jan 2021-May 2023. Nulliparous women were included to measure angiogenic factors between 35-36.6 weeks. Managing health professionals remained blinded to the levels of angiogenic factors. The primary outcome of this study was SGA newborn (birthweight <10th percentile), FGR (SGA + PE and/or adverse perinatal outcome) and PE. A total of 423 women were included; 61 newborns (14.4%) were SGA at birth, of which 17 (27.9%) were FGR. A total of 19 (4.7%) women developed pre-eclampsia (PE), of which 8 (2%) within 2 weeks of inclusion. The sFlt1-PlGF ratio sensitivity for SGA and FGR was 23% and 41.2%, respectively. The sensitivity for overall PE was 52.5% and for PE within 2 weeks 75%. The specificity of the ratio was similar across all outcomes, ranging between 85.7% and 86.4%. The positive likelihood ratio (+LHR) for SGA and FGR was 1.63 and 2.88, respectively; for overall PE 3.87 (95% CI: 2.36-6.32) and for PE within 2 weeks 5.51 (95% CI 3.45-8.81). The discriminatory capacity of sFlt1-PlGF for SGA, FGR, overall PE and PE< 2 weeks was an AUC of 60.2%, 66.8%, 79.3% and 91.4%, respectively. sFlt1-PlGF ratio had a limited predictive performance for SGA, it improved moderately for fetal growth restriction and overall PE, and, as previously reported, it was high for PE within 2 weeks.