Surfactant phospholipid ontogeny in fetal rabbit lung lavage and amniotic fluid.

The development of pulmonary surfactant production by the fetal lung is essential for normal lung function at birth. Failure to produce an adequate amount of surfactant is associated with respiratory distress syndrome of the newborn (RDS). Prediction of the risk of RDS is based on the measurement of surfactant phospholipids in amniotic fluid. We have studied on ontogeny of surfactant phospholipids in the fetal rabbit by analyzing samples obtained simultaneously from lung lavage and amniotic fluid during late gestation (days 24-30). A surge in saturated phosphatidylcholine and percent saturation is observed first in lung lavage (day 26), followed 1.5-2.5 days later by a similar increase in amniotic fluid. These findings support the assumption that amniotic fluid surfactant phospholipids reflect the production of surfactant phospholipids in the developing lung.