Role of sex in morbidity and mortality of very premature neonates.

Background The aim of this study was to investigate the effect of sex on survival and short-term outcomes of very low-birthweight infants ( VLBWI) born in Japan. Methods This study included VLBWI who were admitted to neonatal intensive care units participating in the Neonatal Research Network of Japan, between 2003 and 2012. The primary outcome was a composite of mortality or any major morbidity, including neurologic injury, bronchopulmonary dysplasia ( BPD), necrotizing enterocolitis ( NEC), or retinopathy of prematurity requiring treatment. Results The composite primary outcome was worse in male infants. Male infants were also more likely to develop BPD. This difference reached statistical significance in neonates born at ≥26 weeks of gestation. In contrast, significant difference in the incidence of NEC was more likely to be seen at 23-25 weeks of gestation. Conclusion Male neonates are more likely to die and are at a higher risk of respiratory and gastrointestinal complications than female neonates. [ABSTRACT FROM AUTHOR]