Maternal inflammatory biomarkers and neonatal characteristics as predictors of bronchopulmonary dysplasia in preterm infants: a retrospective cohort study

Background Maternal peripartum inflammation may contribute to bronchopulmonary dysplasia (BPD) in preterm infants, yet readily available hematologic predictors are underexplored. We evaluated whether the maternal platelet-to-white blood cell ratio (PWR) within 24 h before delivery, together with neonatal clinical variables, predicts BPD. Methods We conducted a retrospective cohort study at a tertiary NICU in Southwest China, including all eligible mother–infant pairs with preterm birth (7 days (aOR = 6.74; 3.34–13.62; p < 0.001). Gestational age and birth weight were protective (per week: aOR = 0.68; 0.58–0.79; p < 0.001; per 100 g: aOR = 0.86; 0.78–0.94; p = 0.001). The final model showed strong discrimination (AUC = 0.866; 95% CI, 0.827–0.905) and good calibration (Hosmer–Lemeshow χ 2 = 10.833, p = 0.211; bootstrap slope = 0.98). At the optimal probability threshold (0.763), sensitivity was 77.2% and specificity was 80.9%. A nomogram enables individualized risk estimation. Conclusion A lower maternal PWR measured immediately before delivery, alongside established neonatal risk factors, independently predicts BPD in preterm infants. This simple hematologic marker, integrated into a nomogram, may facilitate early identification and targeted prevention strategies in high-risk dyads.