Transitory congenital hypothyroidism and maternal thyroiditis.

The case histories of two sisters with congenital hypothyroidism are described. Their mother had had high titers of circulating thyroid antibodies during each pregnancy. In the older sister, antibodies were detected at 4 weeks but not a 6 months of age. This girl showed a partial hypothyroidism, that required replacement therapy. However, in the younger sister, the hypothyroidism was reversible and replacement therapy was discontinued after 2 years.