OUTCOME IN 3 SIBLINGS WITH ANTIBODY-MEDIATED TRANSIENT CONGENITAL HYPOTHYROIDISM

A woman receiving thyroxine substitution therapy for acquired hypothyr oidism caused by autoimmune thyroiditis gave birth to three babies who had transient primary hypothyroidism. All three babies had elevated t hyrotropin levels on neonatal screening, but one had normal thyroxine values. Thyrotropin receptor-blocking antibodies were present in mater nal serum and in the three neonates. Each baby also had a different co ngenital malformation. The neurodevelopmental outcome of the children appeared related in part to maternal thyroxine levels, which suggests that transplacental transfer of thyroxine may protect the fetal brain.