Soluble fms‐like tyrosine kinase‐1 and placental growth factor as predictors of adverse maternal events in women with a confirmed diagnosis of preeclampsia

Abstract Objective Soluble fms‐like tyrosine kinase‐1 (sFlt‐1) and placental growth factor (PlGF) have been identified as predictors for preeclampsia and time to birth in women with suspected preeclampsia. This study aims to investigate these markers as predictors of adverse maternal events in women with confirmed preeclampsia. Study design This was a prospective observational cohort study. Pregnant women admitted to hospitals due to preeclampsia were included from May 2019 to May 2024. Main outcome measures The primary outcome was a composite of adverse maternal events (maternal mortality, eclampsia, stroke, cortical blindness, retinal detachment, pulmonary edema, acute kidney injury, liver capsule hematoma or rupture, placental abruption, postpartum hemorrhage, elevated liver enzymes, thrombocytopenia, admission to intensive care unit (ICU) required, and intubation and mechanical ventilation), with the individual components as secondary outcomes. Kaplan–Meier and receiver operating characteristic curves were constructed for sFlt‐1, PlGF, and the sFlt‐1/PlGF ratio. Area under the curve (AUC), sensitivity, specificity, positive and negative predicted value, and likelihood ratio were calculated. Results A total of 307 women were enrolled, of which 36.5% gave birth preterm. In total, 129 women developed 166 adverse maternal events. The most common adverse maternal events were postpartum hemorrhage ( n = 82, 26.7%), elevated liver enzymes ( n = 34, 11.1%), acute kidney injury ( n = 24, 7.8%), and low platelet count ( n = 18, 5.9%). sFlt‐1 showed the best predictive performance, with an area under the receiver operating characteristic curve for the composite outcome of 0.59 (95% confidence interval CI 0.52−0.65), corresponding to a sensitivity of 67% and a specificity of 50%. PlGF and the sFlt‐1/PlGF ratio did not predict the composite outcome. sFlt‐1 showed a modest predictive performance for thrombocytopenia (AUC, 0.68; 95% CI, 0.56–0.81), elevated liver enzymes (AUC, 0.68; 95% CI, 0.59–0.78), and renal impairment (AUC, 0.72; 95% CI, 0.60–0.83). Results remained similar in subgroup analyses of early‐ and late‐onset, and preterm and term preeclampsia. Conclusion SFlt‐1 and PlGF show limited value in predicting adverse maternal events in women with preeclampsia in a high‐income country setting, irrespective of early or late disease. sFlt‐1 may be useful for predicting the individual outcomes of thrombocytopenia, elevated liver enzymes, and acute kidney injury.