Pulmonary hypoplasia in a regional perinatal unit

83 cases of pulmonary hypoplasia were found in 709 perinatal necropsies in St. Mary's Hospital between 1976 and 1983. 49 of these infants were inborn, representing an incidence of 1.4 per 1000 births. Diaphragmatic hernia was present in 43% and was the commonest reason for referral, usually to the neonatal surgical unit, from an outside hospital. Renal malformation, often with oligohydramnios, was seen in 25%, and 11% had no other major disease. The respiratory symptoms associated with pulmonary hypoplasia in the absence of diaphragmatic hernia seem to have encouraged the referral of these infants to the neonatal medical unit. However, more than half the liveborn infants with pulmonary hypoplasia died during the first postnatal day. In comparison with first week deaths from other causes, short survival was a particular feature of pulmonary hypoplasia in infants weighing less than 2.5 kg and pneumothorax and pulmonary haemorrhage were commoner in term infants with hypoplastic lungs.