Treatment of fetal goiter in utero

We describe a case of fetal goiter diagnosed and treated in utero at a tertiary centre in Melbourne, Australia. A 40-year-old primaparous woman was referred with a suspicion of an enlarged fetal thyroid gland and polyhydramnios at 29 weeks of gestation. There was a maternal euthyroid state but elevation of anti-TSH-receptor, antithyroglobulin and antithyroid peroxidase (anti-TPO) antibodies. On review at 32 weeks, there was an anterior, bilobed, homogenous hypoechoeic neck mass with peripheral vascularity measuring 46 × 40 × 26 mm, consistent with a fetal goiter, along with polyhydramnios. Magnetic resonance imaging at 32+5 weeks confirmed the presence of a fetal goiter and suggested esophageal and tracheal obstruction. A multidisciplinary team was convened to discuss mode of delivery given the suspected tracheal compression, including the potential for an EXIT (ex utero intrapartum treatment) procedure to facilitate safe birth. Cordocentesis was performed at 33+5 weeks in accordance with the patient's wishes to investigate fetal thyroid function and demonstrated markedly increased TSH >46.3mU/L (normal 0.4-4.80mU/L), with normal levels of free thyroxine and free triiodothyronine. Anti-TPO antibodies were also detected at 155.0IU/mL (normal 0-9IU/mL). A treatment plan was devised of weekly intra-amniotic injections with 400 mcg of levothyroxine. Weekly intra-amniotic injections with levothyroxine began at 33+6 weeks of gestation, with a total of six doses given prior to a planned delivery at 39+5 weeks. Weekly TSH measurements in the amniotic fluid revealed good response to treatment, with resolution of the goiter and normalisation of the amniotic fluid volume after three doses. The fetus was delivered by Caesarean section at 40+0 after failed induction of labour. The Apgar scores were 9 at 1 minute and 9 at 5 minutes, requiring no resuscitation at birth. Postnatal imaging showed a mildly enlarged thyroid, and the neonate remains on treatment with oral levothyroxine.