Predictors of neonatal mortality in Iranian cases of preterm birth: a retrospective cohort study

INTRODUCTION: Although the risk factors of neonatal mortality are currently known, it was necessary to know the risk factors of mortality in neonatal preterm birth. The present study was conducted to find and investigate the potential maternal, fetal and neonatal risk factors of neonatal mortality among the cases of preterm birth. METHODS: 2020 were included in the study using census. Mixed model logistic regression was used to identify the potential risk and protecting factors from a selected groups of the variables of the national registry with reporting odds ratio (OR) and 95% confidence interval (CI). RESULTS: A total of 120,688 cases of preterm labor were studied with GA in the range of 22-36 weeks. A total of 5458 neonatal deaths (4.52% of total cases) were recorded. The most effective protecting factor was increased gestational age (GA) (adjusted OR = 0.664 per week, 95% CI: 0.658-0.669). The risk factors remained in the multivariable modeling were maternal hypertension, eclampsia / preeclampsia, addiction, placental abruption, meconium staining, impaired fetal heart rate, previous neonatal death, intrauterine growth restriction, lack of corticosteroid administration, rural and nomadic residency, cesarean delivery, malformation, public hospital (vs. private), and out-of-hospital delivery (P < 0.1). The protecting factors remained in the multivariable modeling were gestational diabetes mellitus, premature rupture of membrane for more than 18 h, female sex, GA, and mother age (P < 0.1). CONCLUSION: The present study showed that many maternal and neonatal related variables were potential risk and protecting factors of neonatal death among the preterm birth neonates. The main predictor of the outcome was GA, and using corticosteroid before birth was a modifiable protecting factor.