Acceleration of fetal maturation with intra-amniotic thyroxine in the presence of maternal malignancy.

Acceleration of fetal maturation with intra-amniotic administration of thyroxine was employed in eight patients in whom preterm delivery was necessary because of malignant disease of the mother. Thyroxine (200 mcg to 500 mcg) was given at weekly intervals starting at the 27th to 32nd week of gestation until the L-S ratio exceeded 2.0. The fetuses were delivered between the 29.4 and 34.0 week. None of the newborns suffered from respiratory distress syndrome, and three newborns were cared for in the regular nursery. Thyroxine-induced acceleration of fetal maturation and pre-term delivery permits earlier initiation of antineoplastic and radiation therapy without exposing the fetus to the hazards of maternal therapy and those of prematurity.