PROLONGED SUPPRESSED THYROID-STIMULATING HORMONE LEVELS IN HYPERTHYROIDISM IN A NEONATE BORN TO A MOTHER WITH GRAVES-DISEASE

We report here a case of neonatal hyperthyroidism born to a mother, wh ose pregnancy was complicated by poorly controlled Graves' disease. Th e patient demonstrated exophthalmos and marked goiter at birth, indica ting the existence of thyrotoxicosis in utero. The mother's Graves' di sease was well controlled in the third trimester, resulting in a sligh tly lower level of free thyroxine (FT,) in the umbilical cord blood se rum; however, thyroid-stimulating hormone (TSH) was undetectable. Thyr oid-stimulating hormone remained undetectable for 2 months, while FT, levels varied in the course. This case suggests that severe and prolon ged thyrotoxicosis in utero, due to poor control of pregnancy with Gra ves' disease, might induce unresponsiveness of the hypothalamo-pituita ry system in the newborn.