Massive fetal goiter treated by intra-amniotic injection of levothyroxine: a case report.

Objectives: Fetal dyshormonogenetic goiter is a rare condition associated with perinatal complications and sequelae in infants. Although prenatal management remains controversial, further evidence is required for optimal management.

Case presentation: A 30-year-old pregnant woman with no history of thyroid disease was referred to our hospital with polyhydramnios. Fetal ultrasonography revealed fetal goiter. Cordocentesis revealed increased thyroid-stimulating hormone (TSH) and low levels of free thyroxine 4 (fT4), which was the basis of diagnosis of fetal hypothyroidism. Intra-amniotic injections of levothyroxine were administered, resulting in a reduction in the goiter size, amount of amniotic fluid, and level of maternal TSH. The mother was euthyroid during pregnancy. The infant was delivered vaginally at full term with a normal thyroid size and no respiratory disorders except hypothyroidism. At 2 years of age, her neurodevelopment is normal.

Conclusions: Intra-amniotic injections of levothyroxine for fetal hypothyroidism with massive goiter and polyhydramnios may improve perinatal outcomes.