Acceleration of pulmonary surfactant maturation in stresses pregnancies: a study of neonatal lung effluent.

To determine the maturation of pulmonary surfactant at birth, phospholipid patterns in tracheal or pharyngeal aspirates of 54 newborn infants were analyzed by two-dimensional thin-layer chromatography. The compositions of phospholipids and their surface tension-lowering abilities were assessed after gestations with various complications. Preterm infants with respiratory distress syndrome (RDS) lacked phosphatidylglycerol and had lower lecithin/sphingomyelin ratios than infants without RDS. An acceleration of both phosphatidylcholine (lecithin) and phosphatidylglycerol concentrations was observed in 21 preterm infants born after prolonged rupture of the membranes and treatment with isoxuprine. In these infants, the phospholipid pattern of lung effluent was similar to that of term infants even at gestational ages less than or equal to 30 weeks. Biochemical lung maturation was delayed in aneccephalic infants, infants of diabetic mothers, and one infant of a mother with hypothyroidism.