Necrotizing enterocolitis: risk factors and predictive modeling in a cohort of preterm infants. A case-control study

Background: Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in preterm infants. Multiple risk factors have been reported, with inconsistent findings across studies. This study aimed to identify perinatal and postnatal risk factors associated with NEC in very preterm infants and to develop a predictive model for clinical use. Methods: We conducted a retrospective case-control study including infants <32 weeks' gestation and <1,500 g birth weight admitted to a level III NICU between 2018 and 2022. NEC was defined as stage IIA or higher according to modified Bell's criteria and diagnosed within the first 65 days of life. Demographic, clinical, and laboratory data were analysed. Multivariable logistic regression was used to identify independent predictors of NEC and to generate a nomogram. Results: Of 354 eligible infants, 46 (13%) developed NEC. NEC was significantly associated with lower gestational age and birth weight, prolonged rupture of membranes, maternal and neonatal antibiotic exposure, use of umbilical arterial catheters, vasoactive drugs, feeding intolerance, anaemia, and platelet transfusion. In multivariable analysis, early intravenous antibiotic administration within the first 24 h of life and placental abruption remained independent risk factors for NEC (OR: 1.91, 95% CI: 1.1-3.3; and OR: 2.72, 95% CI: 1.27-6.14, respectively). The predictive model demonstrated moderate discriminatory ability (AUC = 0.73, 95% CI: 0.68-0.78). Conclusion: Early intravenous antibiotic administration and placental abruption were independently associated with NEC in very preterm infants. The proposed nomogram may support early risk stratification and closer clinical surveillance using readily available clinical variables. Further multicentre studies are required to validate this predictive tool and assess its clinical utility.