sFlt-1/PlGF Ratio as a Central Biomarker for Preeclampsia and Perinatal Outcomes: A Multisystem Retrospective Cohort Study

Background: Preeclampsia is a major cause of maternal and perinatal morbidity, characterized by placental dysfunction and angiogenic imbalance. The soluble fms-like tyrosine kinase-1-to-placental growth factor (sFlt-1/PlGF) ratio has emerged as a promising biomarker for preeclampsia; however, its prognostic value for maternal and neonatal outcomes remains incompletely defined. Methods: This retrospective cohort study included 320 pregnant women, of whom 68 were diagnosed with preeclampsia, and 252 served as non-preeclamptic controls. Maternal serum sFlt-1 and PlGF levels were measured after 20 weeks of gestation at the time of clinical evaluation for suspected hypertensive disorders of pregnancy. Group comparisons, effect size analysis, receiver operating characteristic (ROC) curve analysis, and multivariable regression models were used to assess diagnostic performance and associations with maternal and neonatal outcomes. Results: The sFlt-1/PlGF ratio was significantly higher in women with preeclampsia compared with non-preeclamptic pregnancies (58.5 ± 17.3 vs. 34.6 ± 19.0; p < 0.001; Cohen’s d = 1.31). ROC analysis demonstrated good discriminative ability for preeclampsia (AUC = 0.81, 95% CI: 0.75–0.87), with a high negative predictive value. Increasing sFlt-1/PlGF values were independently associated with earlier gestational age at delivery, lower birth weight, reduced Apgar (Appearance, Pulse, Grimace, Activity, and Respiration) score, and a higher likelihood of neonatal intensive care unit admission. Conclusions: The sFlt-1/PlGF ratio is a robust biomarker for preeclampsia, providing both diagnostic discrimination and prognostic information regarding maternal and neonatal outcomes. Its integration into clinical practice may support clinical risk awareness when interpreted in the context of standard clinical evaluation and support informed decision-making in pregnancies with suspected or confirmed preeclampsia.