Maternal hypothyroidism in autoimmune thyroiditis and the prognosis of infants.

We evaluated the developmental prognosis of 31 infants born to mothers with autoimmune thyroiditis. Four of the babies developed transient neonatal hypothyroidism. Their mothers all had low thyroid hormone concentrations during pregnancy. Neonatal thyroid function tended to correlate with maternal thyroid function at delivery in babies born to mothers with Graves'disease who were taking antithyroid drugs. Since severe fetal hypothyroidism sometimes results in neurological damage, it is important to maintain normal maternal thyroid function during pregnancy.