[Prevention of hyaline membrane disease by intraamniotic administration of thyroxine]

The best management of respiratory distress syndrome (RDS) is prevention. Prenatal administration of Cortico-steroids has been proved to be a valuable way for accelerating fetal lung maturation. In case of high risk pregnancy, however, where acceleration of lung maturation is most needed, there may be a relative contraindication for using steroids. According to the theory that the increase in the phospholipid component of surfactant may be mediated by intra-amniotic thyroxin administration, its use for accelerating human fetal lung maturation has been tested. Seven samples of amniotic fluid were obtained in order to determine the lung maturity in seven pathological pregnancies (pre-eclamptic toxemia, diabetes, infection, hypertension, placental insufficiency) prior to elective caesarean section. Since thyroxin does not cross the placenta, it has to be injected directly into the amniotic sac. 20 ml of clear fluid were obtained by amniocentesis prior to each injection of 250 micrograms of Levothyroxin through the same needle. Each of the infants was delivered before 34 weeks. Birth weights of the premature infants were between 1220-1870 grams. In all cases the Lecithin/Sphingomyelin Ratio (L/S) in amniotic fluid analysis was immature. After thyroxin administration L/S Ratio was mature in pharyngeal aspirate examination after delivery in 6 cases. RDS was seen in only one infant. The interval between intraamniotic administration of T4 and delivery ranged from 72 hours to 2 weeks in 6 cases. In one case with clinical and radiological signs of RDS the injection-delivery interval was less than 48 hours: the L/S Ratio in pharyngeal aspirate was immature 2,8 (normal greater than 3).(ABSTRACT TRUNCATED AT 250 WORDS)