SFlt-1/PlGF ratio for the prediction of preeclampsia in asymptomatic women

Objective:The ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) over placental growth factor (PlGF) increases prior to clinical onset in women with suspected preeclampsia.We aimed to estimate its value in asymptomatic patients. Methods:We recruited nulliparous patients in the first trimester, invited to attend a 20-24, 30-34 weeks' gestation visit for maternal blood sampling used for measurement of the sFlt-1/PlGF ratioanalyzer).The primary outcome was preeclampsia stratified by gestational age at delivery: preterm (<37 weeks) subdivided into early (<34 weeks) and late (34-36 weeks) preterm; and term (37 weeks) preeclampsia.Analyses included area under the receiver operating characteristic curves and the Youden index.Results: Among 845 women recruited, 832 (98%) had complete data, including 4 (0.5%) early, 4 (0.5%) late preterm, and 26 (3.1%) term preeclampsia.At 20-24 weeks' gestation, the sFlt-1/PlGF ratio was highly associated with early (AUC: 0.99, 95% CI: 0.99-1.00;sensitivity: 100% specificity: 99%) but not late preterm or term preeclampsia.At 30-34 weeks, the sFlt-1/PlGF ratio accurately discriminated preterm cases (AUC: 0.96; 95% CI: 0.89-1.00;sensitivity: 86% specificity: 98%) and moderately discriminated term cases (AUC: 0.71; 95% CI: 0.58-0.83;sensitivity: 42% specificity: 93%). Conclusion:Maternal sFlt-1/PlGF ratio is increased at 20-24 weeks' gestation among asymptomatic women who will develop early preeclampsia and at 30-34 weeks among those who will develop preterm preeclampsia.The discriminatory performance of the sFlt-1/PlGF ratio varies according to gestational age at screening and gestational age at delivery.