Acceleration of fetal lung maturation following prolonged rupture of the membranes

Prolonged rupture of the membranes exerts an accelerating effect on fetal lung maturation independent of gestational age or birth weight and resulting in absence of the respiratory distress syndrome (RDS). Sixty-four true-premature infants born of mothers with no complications of pregnancy other than prolonged rupture of the membranes were evaluated for the presence of RDS. In 42 of these infants, membranes were ruptured 24 hours or less prior to delivery, and RDS occurred in 64 per cent. In 22 infants with membranes ruptured more than 24 hours prior to delivery, 31 per cent developed RDS. Lecithin/sphingomyelin ratios showed marked acceleration following membrane rupture, irrespective of gestational age.