IMPE Abstracts

Fetal goiter is an extremely rare complication of pregnancy, presenting with a fetus with hypo or hyperthyroidism. A 24-year-old woman with a history of subclinical hypothyroidism at 6 weeks gestation and treated with levothyroxine was referred to our hospital at 22.5 weeks gestation with a report of an anterior cervical mass of 3.4 cm x 1.3 cm found on her structural ultrasound. Her last TSH was 4.38 uUI/mL, free T4 1.15 ng/dL. An MRI was performed at 26 weeks gestation, reporting an enlarged thyroid gland hypointense in T2 and hyperintense in T1, with measurements of the right thyroid lobe 2.7 x 2.1x 2 cm, left thyroid lobe of 2.7 x 2.1 x 1.5 cm and isthmus of 0.8 cm, approximate volume 10.3 ml, that displaced the airway and decrease 25% of its caliber in the poscricoid region. Fetal blood and amnionic fluid samples were collected at 28.3 weeks gestation, obtaining TSH 29.2 uUI/mL, free T4 1.55 ng/dL, as well as maternal TSH was 1.63 with free T4 1.29. Maternal antibodies were positive. It was decided to start treating with a weekly amniotic injection of levothyroxine to prevent further airway compromise and to keep the fetus in an euthyroid state. The patient underwent vaginal delivery at 35 weeks gestation. The infant’s weight was 2170 g, length 45 cm, head circumference 35 cm, had visible goiter, and a Letarte scale at 2 points presenting dry skin and difficulty feeding. No dysmorphic features were found. TSH at birth was 48.7 uUI/mL, and at 48 hours was 22.8 uUI/ml. Ultrasound at 24 hours reported a thyroid volume at 7.7 cc. Levothyroxine was administered immediately before feeding. Difficulty feeding was resolved at 3 days of age, and both mother and infant were discharged.