Sex Difference in Disability and Handicap at Five Years of Age in Children Born at Very Short Gestation

Objective. The objective of this study was to examine the relationship between sex and disabilities or handicaps at 5 years of age in infants born at less than 32 weeks gestation. Design. From the nationwide collaborative survey starting in 1983, including perinatal data obtained during routine perinatal care and follow-up assessments by the attending pediatricians, data from 1008 infants fulfilling the criteria were used. At age 5 years, a detailed assessment was performed by three specially trained pediatricians in 96% surviving infants (n = 648), of which 345 were boys. Each child was categorized as disabled or handicapped, using World Health Organization definitions. Results. The prevalence of handicaps was three times greater in boys than in girls (21% vs 7%, odds ratio 3.2). Adjustment for gestational age and birth weight (logistic regression analysis) did not change this (odds ratio 3.5). Further adjustment by including perinatal variables such as idiopathic respiratory distress syndrome did not alter the odds ratios. The male excess in handicaps was not related to lower mortality, and therefore was not a mere consequence of a higher survival rate. The excess in handicaps was found in all assessed areas. Conclusions. Infants' sex seems to be an important determinant of handicaps. The perinatal variables used in the present study do not explain the difference in handicaps. These findings emphasize the need to include the sex distribution of a study population more systematically in analyses in future studies concerning long-term outcome of very preterm birth or low birth weight.