The male disadvantage in very low birthweight infants: does it really exist?

In a nationwide collaborative study in the Netherlands, perinatal and follow up data were collected on 1338 liveborn very preterm (less than 32 weeks) and/or very low birthweight (VLBW) infants (less than 1500 g). In this group, the mortality risk was similar for both male and female infants. The handicap risk, however, was significantly greater for boys than for girls. This finding could not be explained as being due to the well-known delay in lung maturation in male infants as in idiopathic respiratory distress syndrome and need of assisted ventilation.