The incidence of periventricular leukomalacia (PVL) in risk neonates was evaluated among 300 risk neonates in a prospective ultrasound study at the Pediatric Clinic of the Medical Faculty, University of Rostock. Perinatal risk factors for the development of PVL and gestational age were taken into consideration. Maternal infections during pregnancy were found to be a risk factor for development of PVL. A severe hyaline membrane disease was more frequently diagnosed in highly immature preterm neonates with postnatal PVL. The percentage of highly immature preterm neonates with postnatal PVL and severe hyaline membrane disease was higher in vaginal-born risk neonates. A correlation between 1-minute Apgar scores < or = 3 and postnatal PVL was found in more mature preterm neonates.