Large fetal goiter due to placental passage of maternal antithyroperoxidase antibodies.

We report a case of fetal goiter in a pregnant woman with Graves-Basedow disease. It was diagnosed in the third trimester by a routine ultrasound, and the cordocentesis verified increased levels of thyroxine (T4) and increased autoantibodies (antithyroperoxidase antibodies) that were also increased in maternal blood. Fetal goiter got smaller on the follow-up scans, and the newborn presented hypothyroidism. Current notions on the diagnosis and management of fetal goiter are briefly discussed.