TSH receptor-stimulating or TSH receptor-binding antibodies in the mother can cross the placenta, and affect the babys thyroid. If a woman is positive for these antibodies during pregnancy, her baby can be born with hyperthyroidism. These antibodies should, therefore, be measured in women who have Graves disease, or who have had previous newborns who developed Graves disease. Treatment of the mother with antithyroid drugs may be necessary to reduce the risk to the newborn.
If a woman with elevated TSH receptor-stimulating or TSH receptor-binding antibodies is treated with antithyroid drugs, fetal ultrasound evaluation should be conducted. This ultrasound should look for evidence of thyroid dysfunction in the developing baby including slow growth and enlarged thyroid, among other signs.
If a new mother has Graves disease, her newborn should be evaluated for thyroid dysfunction after birth.