Outcome of pregnancy in a hypothyroid woman with resistance to thyroid hormone treated with triiodothyronine.

Epidemiological and research data have shown the significant role of maternal thyroid hormone in fetal neurologic development. It has been suggested that maternal hypothyroxinemia is potentially damaging for the neurodevelopment of the fetus, independently of T3 levels. We present a pregnant woman with resistance to thyroid hormone and iatrogenic hypothyroidism who was treated with triiodothyronine during the whole pregnancy. Even though maternal hypothyroxinemia was severe the children showed a normal neuropsychological development.