Prolonged rupture of membranes, pre-eclamptic toxaemia, and respiratory distress syndrome.

A retrospective analysis was made of the incidence and severity of the idiopathic respiratory distress syndrome (RDS) in babies of less than 35 weeks' gestation born at this hospital from January 1967-December 1974. There was a lower incidence of RDS in babies born after pregnancies complicated only by prolonged rupture of membranes (PRM) (19%) and in babies born vaginally after pregnancies complicated only by pre-eclamptic toxaemia (PET) (18%) compared with the incidence of RDS after uncomplicated pregnancies (35%). Babies born vaginally who developed RDS after pregnancies complicated by PRM or PET had less severe disease compared with those who developed RDS after uncomplicated pregnancies. Mortality in babies who developed severe RDS was not influenced by the occurrence of PRM or PET. The biological implication of the study is that certain complications of pregnancy may accelerate pulmonary surfactant production in preterm babies.