Do Premature Female Infants Really Do Better Than Their Male Counterparts?

Abstract

We compared survival and outcomes in process of care in female versus male infants born ≤32 weeks gestational age (GA). Data were obtained from the Alere database for infants born ≤32 weeks GA. Females were compared with males for demographics, complications, and care processes. Univariate and multivariate analysis was conducted using chi-square analysis, analysis of variance, or logistic regression. Of the infants included, 6086 female and 6721 males were included. Mean GA did not differ, males were born larger than females, and females were more likely to be born SGA. Males received more surfactant, developed more CLD, received more steroids, and more often required oxygen at discharge. Females were more likely to develop a patent ductus arteriosus. After controlling for body weight, GA, and small-for-GA status, females were more likely to survive (95.4% versus 93.6%, odds ratio 1.63, P < 0.01). Male sex did not play a role in other processes of care except for weaning to a crib. Male infants born ≤32 weeks GA have a decreased rate of survival and an increased rate of respiratory morbidity in spite of higher birth weight distributions. Sex did not play a role in other processes of care.

Role of sex in morbidity and mortality of very premature neonates

“…In this comparative study of male and female VLBWI outcomes in Japan, differences in mortality and morbidity between these two sex groups were identified. Previous reports in neonatology have described a significant female advantage for survival and short‐term outcomes, including BPD, surfactant use, home oxygen therapy, severe ROP, hyperbilirubinemia, IVH, PDA, neurodevelopmental impairment, and combined adverse outcomes of BPD, NEC, ROP, or IVH . Contrary to these earlier reports, in the present study there was no difference in the rates of ROP and PDA requiring treatment.…”

“…Preterm male infants are at a significant disadvantage compared with female infants of similar gestational age (GA) in terms of morbidity and mortality . They have worse respiratory and neurodevelopmental outcomes than female infants, with higher incidences of respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), and intraventricular hemorrhage (IVH) . Mechanisms underlying sex‐specific patterns of morbidity and mortality are not yet fully understood.…”

Respiratory adaptation and surfactant composition of unanesthetized male and female lambs differ for up to 8 h after preterm birth

“…ale preterm infants are at a greater risk of developing respiratory distress syndrome than females of the same gestational age (1)(2)(3)(4). Accordingly, male sex is associated with a greater risk of neonatal mortality and respiratory illness including BPD (5)(6)(7).…”

Sex differences in cardiorespiratory transition and surfactant composition following preterm birth in sheep

“…IT IS NOW WIDELY RECOGNIZED THAT, following preterm birth, males have a greater risk of death and illness compared with females (14,39,40,52), although the difference in mortality between males and females has declined in recent years (6,13).…”

“…Most studies indicate that this increased risk in male preterm infants is a result of a greater incidence of respiratory insufficiency than females (14,52). The greater incidence of respiratory distress syndrome (RDS) in male preterm infants compared with females (39,48), suggests less mature lungs in males compared with females of the same gestational age.…”