Neonatal and infant outcome in boys and girls born very prematurely

Pediatr Res. 2012 Mar;71(3):305-10. doi: 10.1038/pr.2011.50. Epub 2012 Jan 18.

Abstract

Introduction: Although important new strategies have improved outcomes for very preterm infants, males have greater mortality/morbidity than females. We investigated whether the excess of adverse later effects in males operated through poorer neonatal profile or if there was an intrinsic male effect.

Results: Male sex was significantly associated with higher birth weight, death or oxygen dependency (72% vs. 61%, boys vs. girls), hospital stay (97 vs. 86 days), pulmonary hemorrhage (15% vs. 10%), postnatal steroids (37% vs. 21%), and major cranial ultrasound abnormality (20% vs. 12%). Differences remained significant after adjusting for birth weight and gestation. At follow-up, disability, cognitive delay, and use of inhalers remained significant after further adjustment.

Discussion: We conclude that in very preterm infants, male sex is an important risk factor for poor neonatal outcome and poor neurological and respiratory outcome at follow-up. The increased risks at follow-up are not explained by neonatal factors and lend support to the concept of male vulnerability following preterm birth.

Methods: Data came from the United Kingdom Oscillation Study, with 797 infants (428 boys) born at 23-28 wk gestational age. Thirteen maternal factors, 8 infant factors, 11 acute outcomes, and neurological and respiratory outcomes at follow-up were analyzed. Follow-up outcomes were adjusted for birth and neonatal factors sequentially to explore mechanisms for differences by sex.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Infant, Newborn
  • Infant, Premature*
  • Infant, Premature, Diseases / epidemiology*
  • Lung Diseases / epidemiology*
  • Male
  • Nervous System Diseases / epidemiology*
  • Sex Characteristics*
  • United Kingdom