Foetal goitrous hypothyroidism — Easy to recognise, difficult to treat. Is combined intra-amniotic and intravenous L-thyroxine therapy an option?

Abstract

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 hyperextension, 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 hypothyroidism 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 vaginally 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 intravenous 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 ineffective 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.