Increased incidence of respiratory distress syndrome in infants following pregnancies complicated by hypertension.

We assessed the relationship between maternal hypertension during pregnancy and the incidence of respiratory distress syndrome (RDS) in 263 infants born at 32 weeks' gestation or less. Two-hundred and twenty-three mothers were normotensive and 40 were hypertensive. RDS occurred significantly more commonly in infants of hypertensive mothers than in controls (60% vs 33%; p = 0.001). The association between maternal hypertension and an increased rate of RDS remained after adjustment for differences between groups with respect to gestational age, mode of delivery, administration of antenatal steroids and other complications of pregnancy, except for delivery in the absence of labour. The increased rate of RDS related to the severity of hypertension but did not relate to the duration of hypertension or to maternal treatment with beta-blockers. In those infants who developed RDS there was no significant difference in the severity of the illness between the hypertensive group and the controls.