Gestational age-specific sex difference in mortality and morbidities of preterm infants: A nationwide study

Area of Science:

• Neonatalogy
• Perinatal Medicine
• Pediatric Epidemiology

Background:

• Sex differences in outcomes for preterm infants are not fully understood.
• Very low birth weight infants (VLBWI) <30 weeks gestation face significant mortality and morbidity risks.
• Gestational age is a critical factor influencing outcomes in preterm neonates.

Purpose of the Study:

• To investigate the adverse effects of male sex on mortality and morbidities in very low birth weight infants (<30 weeks gestation).
• To analyze sex-specific effects stratified by gestational age, accounting for perinatal risk factors.
• To identify specific morbidities associated with male sex in preterm neonates.

Main Methods:

• Population-based study using the Korean Neonatal Network data.
• Inclusion of VLBWI born between 23 and 29 weeks gestation (January 2013 - December 2014).
• Analysis of gestation-specific sex differences in mortality, combined morbidities, and individual morbidities.

Main Results:

• No significant difference in mortality between male and female VLBWI.
• Males ≤25 weeks gestation had higher risks of bronchopulmonary dysplasia and combined morbidities (OR 2.08 and 2.00, respectively).
• Males showed higher incidence of periventricular leukomalacia; females >25 weeks had higher risk of severe retinopathy of prematurity.

Conclusions:

• Male sex is an independent risk factor for major morbidities in VLBWI, particularly those born at ≤25 weeks gestation.
• While mortality risks are similar, specific morbidities exhibit distinct patterns related to sex and increasing gestational age.
• Gestational age-stratified analysis is crucial for understanding sex-based disparities in preterm infant outcomes.