IMPE Abstracts

Introduction: The prenatal diagnosis of fetal goiter is made by ultrasonography (US). Occasionally, clinical history and US findings may lead to the presumptive diagnosis of fetal hyper or hypothyroidism. Although, the dosage of thyroid hormones in fetal blood may exceptionally be necessary.

Objective: To report the prenatal treatment and postnatal evolution of a child with fetal goiter.

Prenatal treatment: A primigesta 45-year old woman, was referred for diagnosis of fetal goiter at 28 weeks of gestation. She had a history of total thyroidectomy for a thyroid nodule, on treatment with levothyroxine 150 mg/d. US showed a single masculine fetus, weight 1240 g (p85), normal fetal cardiac frequency (FCF), thyroid circumference > pc 95 and Doppler with a peripheral pattern; goiter caused tracheal compression and cervical hyperextension. At 29nd weeks cordocentesis showed levels of TSH 119 uU/mL, T4 3 mg/dl, fT4 0.6 ng/dl, T3 0.3 ng/ml and amniocentesis TSH 1.34, T4 <3, fT4 < 0.5, T3 <0.3. Treatment was performed using 8 weekly intra-amniotic injections with LT4 doses of 200 to 400 mg. At 31^rd week cord blood values were TSH 21, T4 5.2, fT4 0.7, T3 < 0.4; US showed shrinkage of the fetal goiter and normal FCF.

Postnatal evolution: Birth by cesarean section scheduled at 37 weeks, with adequate weight of 3000 gr. The newborn had a normal physical exam and a non-palpable thyroid. Thyroid US showed left lobe: 19x10x 10 mm; right lobe: 15x10x10 mm, with heterogeneous echo structure. Cord blood values were TSH 4.29, T4 5.7, fT4 0.6, T3 0.72. Hypoplasia of distal femur nucleus was evidenced on X-ray. He began treatment with LT4 at 48 hours of life. Peripheral blood DNA screened for thyroglobulin gene (TG) showed the patient was heterozygous for the TG gene pathogenic variants c.5686+1G>T and c.7007G>A, p.(Arg2336Gln). At 14 months of age, absence of goiter, adequate neuromaduratives milestones, with weight and height in pc 25.

Conclusions: The diagnosis and prenatal treatment of fetal goiter is key for achieving fetal euthyroidism and neuro-maturation potential. Due to limited transplacental transport of thyroid hormones, direct intrauterine treatment with intra-amniotic LT4 is needed. Most dyshormonogenesis is transmitted in an autosomal recessive manner. Genetic counseling is of utmost importance.