Cretinism Associated With Maternal Sodium Iodide I 131 Therapy During Pregnancy

Severe hypothyroidism developed in a 4-year-old girl whose mother received four courses of sodium iodide I 131 therapy during pregnancy. Mechanisms of fetal thyroid damage by radioactive iodine include placental transfer, possible concentration of radio-active iodine by the fetal thyroid gland, and possible ablation or partial damage of the fetal thyroid gland by radioactive iodine. Any infant whose mother received¹³¹ I during pregnancy should receive careful long-term follow-up.