Gender differences in rates of unintentional head injury in the first 3 months of life

Objectives.-To assess for gender differences in rates of unintentional head injury in infants less than 3 months of age, to assess the circumstances o f injury in these patients, and to look for gender-related differences in t hese circumstances. Methods.-Two separate databases were analyzed. 1) The National Pediatric Tr auma Registry (NPTR) was queried for all patients less than or equal to 90 days of age who had been diagnosed with unintentional head trauma between 1 990 and 1999. The proportion of males was compared to the expected proporti on of 51%, derived from US census data.. 2) A prospective cohort of 88 infa nts less than or equal to 90 days of age who had been treated for unintenti onal head trauma in an urban pediatric emergency department (ED) was studie d. Circumstances of injury and gender-related differences in these circumst ances were assessed. Results.-In the NPTR database, 600 of 1072 (56%) (95% confidence interval [ CI] 0.53, 0.59) infants less than or equal to 90 days of age were boys (P = .001). In the ED cohort, 54 of 88 (62%) (95% Cl 0.50, 0.72) subjects were b oys (P =.06). In virtually all of the cases described, subjects appeared to be passive participants in the injury. The most commonly reported circumst ances of injury were the following: "child left alone on furniture and fell " (n = 39) or "parent dropped child" (n = 27). Boys accounted for 20 (74%) of the subjects in the "parent dropped child" group (P =.04). Conclusions.-Boys outnumber girls among infants less than 3 months of age w ith unintentional head trauma. These young infants appear to be passive par ticipants in their injuries, which indicates that differences in parenting practices may account for the observed gender differences.