Associations of platelet-to-lymphocyte and neutrophil-to-platelet ratios with adverse perinatal outcomes in severe preeclampsia: a retrospective cohort study

To evaluate the associations of maternal neutrophil-to-platelet ratio (NPR) and platelet-to-lymphocyte ratio (PLR) with adverse perinatal outcomes in pregnancies complicated by severe preeclampsia. A retrospective study was conducted on 524 pregnant women with severe PE. Patients were categorized into a normal group ( n = 418) and an adverse outcome group ( n = 106). The exploratory composite outcome was defined as FGR and/or neonatal asphyxia, with the individual components additionally analyzed as secondary outcomes. Six inflammatory indices (SII, SIRI, MLR, NLR, PLR, and NPR) were compared using the Mann-Whitney U test. Multivariate logistic regression and receiver operating characteristic (ROC) curves were used to assess predictive performance. Lower PLR and higher NPR were observed in the adverse-outcome group ( P = 0.010 and P = 0.005, respectively). After adjustment for gestational age at delivery, 24-h urinary protein, and diastolic blood pressure, PLR remained modestly associated with the composite outcome (adjusted OR per 10-unit increase = 0.950, 95% CI 0.904–0.998, P = 0.042), whereas NPR was not (adjusted OR per 0.01-unit increase = 1.048, 95% CI 0.962–1.142, P = 0.286). In a sensitivity model additionally addressing platelet-related confounding, the PLR association was attenuated (adjusted OR = 0.945, 95% CI 0.891–1.003, P = 0.062).Component-specific analyses suggested different patterns for FGR and neonatal asphyxia, although the latter analysis was limited by only 15 events.Exploratory discrimination was limited; the six-marker model had an apparent AUC of 0.656, which decreased to 0.632 after bootstrap correction for optimism. Lower PLR and higher NPR were associated with adverse perinatal outcomes in unadjusted analyses, but these associations were substantially influenced by gestational age and maternal clinical and hematological factors. The modest discriminatory performance and attenuation of the adjusted associations support interpreting PLR and NPR as exploratory markers rather than established clinical predictors.