Limited Predictive Value of Inflammatory and Renal Markers in the Progression of Isolated Gestational Proteinuria to Preeclampsia: A Retrospective Cohort Study

Objective: Isolated gestational proteinuria (IGP) has traditionally been considered a benign condition; however, emerging evidence suggests that it may represent an early stage in the spectrum of preeclampsia. This study aimed to evaluate clinical and laboratory predictors of progression from IGP to preeclampsia. Methods: This retrospective cohort study included pregnant women diagnosed with proteinuria ≥ 300 mg/day after 20 weeks of gestation between January 2023 and December 2024. After applying predefined exclusion criteria, 319 women with isolated gestational proteinuria (IGP) were included and stratified according to progression to preeclampsia (n = 42, 17.8%). Baseline clinical and laboratory parameters were compared between groups. Multivariable logistic regression analysis was performed to identify independent predictors of progression, and receiver operating characteristic (ROC) curve analysis was used to evaluate the discriminative performance of significant variables. Results: Preeclampsia developed in 17.8% of women with IGP. In multivariable analysis, higher maternal body mass index (aOR 1.085, p = 0.028) and earlier gestational age at diagnosis (aOR 0.883, p = 0.011) were identified as independent predictors of progression. Although neutrophil count and systemic inflammatory indices were elevated in univariate analyses, they did not retain independent predictive value after adjustment. Conclusions: In pregnancies complicated by isolated gestational proteinuria, clinical parameters appear to be more informative than inflammatory and renal markers for predicting progression to preeclampsia. Laboratory-derived indices offer limited additional value and should be interpreted cautiously in risk assessment.