Educational inequalities in neonatal outcomes: a multilevel analysis of a multicenter retrospective cohort study

Maternal educational attainment is an important social determinant of perinatal health; however, its independent association with neonatal outcomes among term infants remains insufficiently defined. We evaluated the association between maternal educational attainment and neonatal intensive care unit (NICU) admission, prolonged NICU length of stay (LOS), and NICU-admitted neonatal mortality in a population of term live-born infants. In this multicenter retrospective cohort study, 7,262 singleton term live births delivered at three tertiary hospitals in Tehran, Iran, between 2023 and 2026 were analyzed. Maternal educational attainment was categorized as under diploma, diploma, bachelor’s degree, and master’s degree or higher. The primary outcomes were NICU admission, prolonged NICU stay (≥ 10 days), and neonatal mortality. NICU-admitted neonatal mortality was assessed among NICU-admitted neonates only. Sequential multivariable logistic regression models were fitted to estimate adjusted odds ratios and 95% confidence intervals after controlling for maternal sociodemographic characteristics, obstetric history, and pregnancy complications. In parallel, multilevel mixed-effects logistic regression models with hospital as a random intercept were fitted to account for between-hospital clustering. Among 7,262 term live births, 1,135 (15.6%) were admitted to the NICU. Among NICU admissions, 354 (31.2%) had a prolonged NICU stay (≥ 10 days) and 73 (6.4%) died. In fully adjusted multilevel logistic regression models with hospital as a random intercept, higher maternal educational attainment was associated with lower odds of NICU admission compared with below-diploma education (diploma: aOR 0.81, 95% CI 0.67–0.98; bachelor’s degree: aOR 0.78, 95% CI 0.66–0.92; master’s degree or higher: aOR 0.72, 95% CI 0.59–0.88). For prolonged NICU stay, the corresponding aORs were 0.66 (95% CI 0.45–0.97) for diploma, 0.66 (95% CI 0.47–0.93) for bachelor’s degree, and 0.32 (95% CI 0.22–0.47) for master’s degree or higher. For NICU-admitted neonatal mortality, the aORs were 0.52 (95% CI: 0.28–0.97) for diploma, 0.43 (95% CI: 0.24–0.76) for bachelor’s degree, and 0.27 (95% CI: 0.12–0.60) for master’s degree or higher. Maternal educational attainment was independently and inversely associated with NICU admission, prolonged hospitalization, and NICU-admitted neonatal mortality among term live-born infants. These findings identify maternal education as a factor associated with neonatal outcomes and may inform policies that integrate educational equity into maternal and newborn health strategies.