Discordance between male and female deaths due to the respiratory distress syndrome.

General neonatal mortality statistics and those for the respiratory distress syndrome (RDS) were examined for the State of Wisconsin from 1979 through 1982. The objectives were to ascertain whether there are differences in total neonatal mortality related to sex and birth weight, to determine the veracity of reported gender differences in deaths due to RDS, and to assess the contribution of other risk factors for neonatal mortality to overall and sex-specific deaths occurring secondary to RDS. Additionally, a prospective analysis was performed at one perinatal center during a 5-year period in attempts to determine whether gender remained a significant factor in deaths due to RDS after adjusting for incidence. Overall, the most frequent diagnoses in those who died were RDS (15.6%), deaths due to complications of pregnancy (8%), immaturity (4.2%), and asphyxia (3.4%). The majority of fatalities for both sexes occur in neonates weighing less than 1 kg and the percentage of deaths attributable to RDS is greatest between 1 and 1.5 kg. The difference between sexes is also maximal in the latter weight group. Deaths secondary to RDS are greater for males regardless of Apgar score at one and five minutes, mode of delivery, maternal age, or ancillary diagnosis. These data suggest that deaths secondary to RDS are consistently greater in male neonates and that delivery within a limited "window" of time during gestation increases male susceptibility to fatal RDS.