The Enlarged Fetal Thyroid: Sonographic and Clinical Findings.

Retrospective review of our OB ultrasound database identified 17 fetuses with enlarged thyroid. Fourteen had a maternal risk factor, most commonly current or prior Graves' thyroiditis. In addition to the enlarged thyroid, abnormalities were identified in 6/17 (35.3%) fetuses. Treatment included adjusting the dose of propylthiouracil, methimazole, or levo-thyroxine, intraamniotic thyroxine, or nothing. Follow-up showed stable fetal thyroid size in 9 and decreased size in 5. Imagers should be aware that fetal goiter can result from maternal hyper- or hypothyroidism. Careful assessment and monitoring of mother and fetus are needed to determine the appropriate cause and treatment of fetal goiter.