Aim: To examine the association between infant mortality, the day of birth and sociodemographic factors.
Methods: This population-based retrospective study analyzed all singleton live births in the state of Missouri during the period 1989 to 1997. The main outcome of interest was infant survival after birth. Hazard ratios (HR) and 95% confidence intervals (CI) for the association between infant mortality and the day of birth were obtained through parametric time to event models.
Results: The neonatal mortality rate was higher on weekends (3.25/1000) compared to weekdays (2.87/1000) (P = 0.042). Cesarean section delivery increased the risk of neonatal death by a magnitude of 31.5 compared to vaginal births (HR = 31.47, 95% CI: 15.79, 62.74). Adolescent females (age <18) were more likely to experience neonatal (HR = 2.20, 95% CI: 1.47, 3.31), post-neonatal (HR = 2.20, 95% CI: 1.47, 3.30) and infant mortality (HR = 4.06, CI: 2.02, 8.14).
Conclusions: Cesarean section delivery heightens the risk of all infant death, including neonatal and post-neonatal death, regardless of the day of birth, underscoring the need for multi-tiered strategies to reduce the occurrence of medically unnecessary cesarean sections. Furthermore, the elevated risk of infant mortality among adolescent mothers highlights the importance of enhanced preconception care and age-appropriate pregnancy prevention interventions.