Survival of Preterm Singleton Deliveries: A Population-Based Retrospective Study

Aim. To identify sociodemographic and medical characteristics associated with preterm birth survival. Methods. A retrospective study of singleton births was performed using Missouri linked data for the years 1978 to 2005. We computed hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazards model. Results. High rates of infant, neonatal, and postneonatal mortality were observed among preterm as compared to term births. White are at low risk for postneonatal (HR = 0.77, CI: 0.65, 0.90) and infant mortality (HR = 0.90, CI: 0.81, 0.99) compared to blacks. We observed increased risks of all mortality types for preterm deliveries by caesarean section (neonatal HR = 1.53, CI: 1.40, 1.68; postneonatal HR = 1.39, CI: 1.22, 1.58; infant HR = 1.37, CI: 1.27, 1.48). As compared to nonsmokers, preterm singletons born to smoking mothers are 69% more likely to experience postneonatal mortality and have a 17% increased risk for infant death. Conclusions. Caesarean section is associated with increased risk of all types of mortality. Racial disparity is still a concern. Further research is required to identify the detailed differences in structure and procedures that result in the disadvantage associated with preterm birth especially with respect to caesarean section and race.