[Comparison of the surface tension of the amniotic fluid with the compliance of the respiratory system of the newborn (author's transl)].

In 51 deliveries between the 27th and 41st week of gestation amniotic fluid was collected ante partum and surface tension measured with the Wilhelmy-balance. The values obtained was compared with the respiratory compliance of the newborns determined immediately post partum. A highly significant correlation (r = -0.83, p less than 0.001) was ascertained. This finding permits a precise prediction of the pulmonary function of the newborn, especially of the especially of the severity degree of a respiratory distress syndrome already by means of amniotic fluid analysis. The less significant correlation between surfactant activity in the amniotic fluid and gestational age (r = -0,48, p less than 0.01) permits the conclusion that pulmonary maturation represents a dynamic process depending upon a variety of known and unknown factors besides the duration of gestation. On the basis of the results of this study the intrauterine and extrauterine fetal risks associated with placental insufficiency can now be estimated more accurately.