Introduction: Foetal hypothyroidism negatively impacts somatic and neurological child development and can be the cause of serious obstetric and perinatal complications. We present a rare case of a large foetal dyshormonogenetic goitre, causing foetal neck hyperexten-sion, oesophageal compression, and cardiac high-output failure.
Material and methods: A foetal goitre complicated by cardiomegaly and polyhydramnios was diagnosed at 23 weeks of gestation (WG) on a routine ultrasonographic (US) assessment in a healthy nullipara. Foetal blood sampling was performed and a severe foetal hypothyroid-ism was diagnosed. Treatment was undertaken with an intra-amniotic followed by combined intra-amniotic and intravenous injections of L-thyroxine (L-T4). A total of 11 doses of L-T4 were administered between 24-37 WG to the foetus.
Results: A complete regression of foetal goitre, cardiomegaly, and polyhydramnios was observed. At 38 WG the patient delivered vagi-nally a male infant with mild hypothyroidism and no signs of goitre or cardiomegaly on postnatal US. Neurological development of the one year old baby is normal.
Conclusions: The effective diminishing of serum TSH concentration and goitre size was reached after combined intra-amniotic and in-travenous L-T4 injections were given. L-T4 requirement in the foetus is equal to or above 15 μg/kg daily and should be given in weekly intervals due to its rapid metabolism by the foetus and by placental type 3 deiodinase. Intra-amniotic L-T4 administration may be inef-fective when a large goitre indisposes amniotic fluid swallowing by the foetus, so then the combined L-T4 injections into the umbilical vein and intra-amniotically in experienced hands seems to be a reasonable and effective option.
Keywords: L-thyroxine in utero treatment; dyshormonogenesis; foetal goitre.