Fetal sex and distribution of peri-intraventricular hemorrhage in preterm infants.

Peri-intraventricular hemorrhage (PIVH) is an important complication of the brain in immature newborn infants. In a real-time ultrasound study with frequent scanning of 78 preterm infants (50 with birth-weight less than 1,500 g and 28 weighing more than 1,500 g), we examined the influence of sex on the occurrence of PIVH. A significant difference between sexes was only found in the group with birth-weight below 1,500 g. PIVH occurred in 72% of male infants and in 28% of females (p less than 0.001). This effect is probably due to a difference in the timing of cerebral vascular maturation in males leading to a difference in the risk of developing PIVH between the sexes before 34 weeks of gestation.