Incidence of bronchopulmonary dysplasia during an 11-year period in infants weighing less than 1500 g at birth.

We studied the occurrence of bronchopulmonary dysplasia (BPD) during an 11-year period in infants weighing less than 1500 g at birth and looked for differences between the periods 1980-1985 (216 infants) and 1986-1990 (217 infants). During the neonatal period, 91 infants died, which gives a neonatal survival rate of 79%. Forty-nine infants developed BPD, which is 11% of all infants and 14% of the infants surviving the neonatal period. The incidence of BPD did not change during the two study periods (11.6% and 11.1%). On the other hand, the study populations changed in many respects. The number of infants with a birth weight of less than 1000 g increased, the incidence of severe RDS increased, and infant mortality decreased. Hence, there was a small decrease in the incidence of BPD in infants surviving the neonatal period from 14.9% to 13.8%. Severe RDS and a birth weight of less than 1000 g were clearly related to the development of BPD. In these two risk-groups the decrease in the incidence of BPD in neonatal survivors was pronounced.