Naples Prognostic Score in Obstetrics: A Novel Tool for Preeclampsia Evaluation

Background: To investigate the predictive value of the mid-trimester Naples Prognostic Score (NPS) for the subsequent preeclampsia development. Methods: This retrospective nested case-control study included 249 women, comprising 120 who developed preeclampsia and 129 normotensive controls, who delivered between January 2019 and January 2024. Laboratory parameters, including complete blood count and biochemical markers, were obtained at 20–24 weeks of gestation. The NPS was calculated based on the neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), serum albumin, and total cholesterol levels, using cutoff values adapted from oncology literature. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to evaluate the predictive performance of the NPS. Results: Women who developed preeclampsia had significantly higher mid-trimester NPS scores compared with controls (median [interquartile range] (IQR): 3.0 (3.0–3.0) vs. 2.0 (1.0–2.0), p < 0.001). ROC analysis demonstrated good diagnostic performance of the NPS (area under the curve (AUC) = 0.886; 95% confidence interval (CI): 0.846–0.926) with an optimal cutoff value of 2.5 yielding a sensitivity of 85.0% and a specificity of 82.9%. In the multivariate logistic regression analysis, the NLR (adjusted odds ratios (aOR) = 4.127), lymphocyte count (aOR = 0.266), serum albumin (aOR = 0.412), and total cholesterol (aOR = 0.993) were identified as independent predictors of preeclampsia, whereas the composite NPS was not retained in the final model. Conclusions: The NPS demonstrated excellent screening performance for predicting preeclampsia, primarily driven by its inflammatory components, particularly the NLR. Although NPS provides practical clinical utility as a composite screening tool, its underlying inflammatory parameters appear to be the true mechanistic predictors. Further validation using pregnancy-specific cutoff values is warranted before routine clinical implementation.