Evaluation of Maternal Serum Placental Protein 13 and Soluble Endoglin as Predictive Biomarkers for Preeclampsia

Abstract

Background: Preeclampsia involves placental dysfunction and maternal endothelial injury that may be reflected by altered placental protein 13 (PP13) and soluble endoglin (sEng). Objective: To evaluate serum PP13 and sEng, individually and jointly, for distinguishing established preeclampsia from healthy pregnancy. Materials and methods: This hospital-based case-control study included 50 women with preeclampsia and 50 healthy pregnant controls; 27 cases were coded mild and 23 severe. Groups were compared using Welch’s t, Mann–Whitney U, or Kruskal–Wallis tests with Holm-adjusted pairwise comparisons. ROC curves quantified discrimination, and repeated five-fold cross-validation assessed internal model performance. Results: PP13 was lower in preeclampsia than controls (84.28 ± 17.97 versus 154.24 ± 25.76; P<0.001; Hedges’ g=−3.13), whereas sEng was higher (17.02 ± 4.42 versus 8.61 ± 3.39; P<0.001; rank-biserial r=0.887). sEng increased across controls, mild, and severe preeclampsia (8.61 ± 3.39, 14.20 ± 2.51, and 20.34 ± 3.85; P<0.001). PP13 remained below control values in both case subgroups but was higher in severe than mild disease. PP13 yielded an AUC of 0.996 (95% CI 0.987–1.000) at ≤112.7, with 96% sensitivity and 98% specificity. sEng yielded an AUC of 0.943 (95% CI 0.898–0.976) at ≥11.2, with 100% sensitivity and 72% specificity. The PP13–sEng model had an apparent and mean cross-validated AUC of 1.000. Conclusion: Lower PP13 and higher sEng strongly distinguished preeclampsia in this sample. Because sampling time and assay specifications were unavailable and thresholds came from a small case-control dataset, the results establish biomarker candidacy rather than prospective prediction. Independent gestational-age-standardized validation is required.