Fetal Goitrous Hypothyroidism

Abstract

We present a first case in whom fetal hypothyroidism with goiter was both successfully diagnosed and treated in utero. An obstetrical sonogram at 33 weeks revealed a bilobed fetal neck mass, compatible with enlarged thyroid gland, associated with neck hyperextension, reduced gastric fluid, and polyhydramnios. Umbilical blood sampling after volume reduction amniocentesis confirmed fetal hypothyroidism with a euthyroid mother. Fetal T₄ measured 1.3 μg/dl, free T₄ 0.3 ng/dl, and thyroidstimulating hormone 186 μU. Intra-amniotic levothyroxine, 500 μg, was given twice with a 14-day interval. The head flexed, gastric fluid increased, and amniotic fluid levels returned to normal. Prenatal (36 weeks) and neonatal blood sampling demonstrated return to euthyroid indices. Ultrasonic estimates of thyroid volume decreased by over 50%. Vaginal delivery at 39 weeks was incomplicated. The newborn appeared normal and is being maintained on thyroid replacement therapy.

Intrauterine Treatment of Thyroid Goiters

“…In fact, T4 cannot be directly administered to the mother [16], and it is not advisable to inject the hormone into the fetus intramuscularly [15] or intravenously. However, intra-amniotic injection is followed by a significant rise in fetal serum T4 concentrations [5,17], Thyroxine is apparently absorbed by the fe tus during deglutition, as has been demon strated in the sheep [ 17,18].…”

“…This 7-day injection interval is the maximum ac ceptable when the fetus is hypothyroid since Dudenhausen [20] has noted that elevated plasma T4 concentrations disappeared from the 5th day after intra-amniotic injection of 500 pg of L-T4 administered to facilitate pulmonary maturation of the fetus with a normally functioning thyroid. However Johnson et al [5] have reported an observa tion of a 39 weeks of gestation born infant. Normal thyroid gland size and function oc curred after only two intraamniotic infu sions of 500 pg of lévothyroxine at 34 and 36 weeks.…”

“…This echogenic mass, which appeared to be homogeneous and avascular in Doppler ultrasonography, was larger than a normal thyroid (10 X 8 X 5 mm at 22 WA). It was located beneath the jaw, anterior to the carotid arteries, and did not extend into the chest area [2][3][4][5] ( fig. 1-3).…”

Intrauterine Diagnosis and Management of Fetal Goitrous Hypothyroidism: A Report of an Iranian Family with Three Consecutive Pregnancies Complicated by Fetal Goiter

“…Advances in ultrasonographic technologies have been associated with the increase in international reports of fetal goiter in English literature as summarized in Table 3 (5,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32). Fetal thyroid enlargement can present with fetal hypothyroidism, hyperthyroidism, or even a euthyroid state (25,27).…”

Intrauterine Treatment of Fetal Goitrous Hypothyroidism Controlled by Determination of Thyroid-Stimulating Hormone in Fetal Serum

“…Graves' disease) [4] or with a defect within the fetal thyroid gland hormone biosynthesis [5]. After testing for maternal thyroid function as well as searching for thyroid antibodies, the next diagnostic step is to perform cordocentesis [6].…”