Role of Gender in Morbidity and Mortality of Extremely Premature Neonates

Abstract

We investigated the effect of gender on survival and short-term outcomes of extremely premature infants (≤27 weeks) born in Canada. The records of infants admitted between 2000 and 2005 to a neonatal intensive care unit participating in the Canadian Neonatal Network were reviewed for infant gender, birth weight, gestational age, outborn status, Score for Neonatal Acute Physiology II, and antenatal corticosteroid exposure. The following outcomes were recorded: survival at final discharge, necrotizing enterocolitis, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage grade ≥3, retinopathy grade ≥3, days on ventilation, and length of hospital stay. Among 2744 extremely premature infants, 1480 (54%) were male and 1264 (46%) were female. Mean birth weight of female neonates was significantly lower at each week of gestational age. Although no significant difference in survival at discharge was found between genders overall, the prevalence of BPD, combined adverse outcomes, and mortality for infants born between 24 and 26 weeks were significantly higher in males. This study suggests that, in the postsurfactant era, males remain at higher risk of respiratory complications and may have higher mortality when born between 24 and 26 weeks of gestation.

High-Frequency Oscillatory Ventilation Versus Synchronized Intermittent Mandatory Ventilation Plus Pressure Support in Preterm Infants With Severe Respiratory Distress Syndrome

“…37 The sex effect on the morbidity and mortality of premature infants has been reported previously. 38 Finally, we included some infants born at 31-32 weeks of gestation, which is relatively mature, although nowadays they would be less likely to be ventilated. However, the number of such patients was very small and probably did not affect our results.…”

Response of vascular endothelial growth factor and angiogenesis-related genes to stepwise increases in inspired oxygen in neonatal rat lungs

“…To test this hypothesis, we determined the response of systemic and pulmonary levels of VEGF and sVEGFR-1, as well as pulmonary angiogenesis gene profiles during graded oxygen exposure in newborn rat pups. Because male infants are at higher risk for respiratory complications (27), we examined gender differences in response to graded oxygen.…”

Sex-dependent changes in the pulmonary vasoconstriction potential of newborn rats following short-term oxygen exposure

“…In humans, neonatal survival is clearly sex dependent, being significantly greater for females, even in the postsurfactant era (12). Given that most of the neonatal mortality relates to premature birth and these neonates usually have surfactant deficiency requiring supplemental O 2 , it is tempting to relate sex differences in the handling of oxidative stress to survival and morbidity.…”

“…Female preterm infants exhibit greater survival and lesser morbidity as compared with male neonates (12). In humans, sex differences in the tolerance to oxidative stress also appear to be present because following exposure to antenatal steroids, the antioxidant capacity is greater in female, as compared with male, preterm infants (13).…”