Fetal cord blood sampling in the diagnosis and the treatment of fetal hyperthyroidism in the offsprings of a euthyroid mother, producing thyroid stimulating immunoglobulins.

We described here three individual pregnancies in a euthyroid mother with a past history of Graves disease and high levels of thyrotropin receptor stimulating antibodies. Ten years prior to her first pregnancy the mother underwent a partial thyroidectomy for Graves disease and remained euthyroid since, but still produced high levels of thyrotropin receptor stimulating antibodies. Fetal and postnatal hyperthyroidism was not recognized for the first child who was referred to us at one year of age for craniostenosis. During the two next pregnancies fetal hyperthyroidism was suspected on the basis of fetal tachycardia, growth retardation, fetal goiter and fetal cord blood sampling confirmed high levels of free T3, free T4, suppressed fetal TSH levels, and high levels of fetal TRAb. The mother received propylthiouracil to control fetal hyperthyroidism. Neither baby was premature and each had a more favorable outcome than the first. Fetal cord blood sampling proved to be useful during these two pregnancies to ascertain the diagnosis of fetal hyperthyroidism and to monitor the dose of PTU administered to this euthyroid mother.