Antenatal diagnosis and treatment of a fetal goiter.

The sonographic diagnosis of a fetal goiter, confirmed at delivery, is described in a fetus exposed to large doses of propylthiouracil, which was administered to the mother. The pregnancy was also complicated by recalcitrant premature labor secondary to polyhydramnios. The intraamniotic instillation of thyroxine decreased the size of the fetal goiter, and numerous therapeutic amniocenteses permitted continuation of the pregnancy, so a mature infant with a goiter but no airway obstruction was delivered. Amniotic fluid reverse-T3 assays confirmed fetal utilization of the thyroxine. Fetal thyroid physiology is discussed briefly along with the benefits of the antenatal sonographic diagnosis of fetal goiter.