Mortality and Adverse Neurologic Outcomes Are Greater in Preterm Male Infants

To determine whether male gender has an effect on survival, early neonatal morbidity, and long-term outcome in neonates born extremely prematurely. Retrospective review of the New South Wales and Australian Capital Territory Neonatal Intensive Care Unit Data Collection of all infants admitted to New South Wales and Australian Capital Territory neonatal intensive care units between January 1998 and December 2004. The primary outcome was hospital mortality and functional impairment at 2 to 3 years follow-up. Included in the study were 2549 neonates; 54.7% were male. Risks of grade III/IV intraventricular hemorrhage, sepsis, and major surgery were found to be increased in male neonates. Hospital mortality (odds ratio 1.285, 95% confidence interval 1.035-1.595) and moderate to severe functional disability at 2 to 3 years of age (odds ratio 1.877, 95% confidence interval 1.398-2.521) were more likely in male infants. Gender differences for mortality and long-term neurologic outcome loses significance at 27 weeks gestation. In the modern era of neonatal management, male infants still have higher mortality and poorer long-term neurologic outcome. Gender differences for mortality and long-term neurologic outcome appear to lose significance at 27 weeks gestation.