Transient hyperthyroxinemia in newborns from women with autoimmune thyroid disease and raised levels of thyroid peroxidase antibodies

Abstract

Objective. Although it is well established that maternal thyroid disease and increased levels of thyrotropin receptor antibodies (TRab) during pregnancy are associated with a number of complications, is the significance of increased levels of thyroid peroxidase antibodies (TPOab) alone a matter for discussion? The aim of the present study was to examine whether transplacental passage of TPOab from women with autoimmune thyroid disease (AITD) interferes with thyroid function in the neonate.

Methods. Pregnant women with AITD (raised levels of TPOab) and their neonates were monitored with regard to variations of thyroid hormones, thyrotropin (TSH), and TPOab. Pregnant women with non-AITD served as controls.

Results. The neonates from mothers with AITD, independently of the presence also of TRab in the mothers, had a transient hyperthyroxinemia one week following birth. Neonatal TPOab correlated with that of the mothers at gestation and was cleared concomitantly with normalization of thyroxine. A high frequency (21%) of severe hyperbilirubinemia was observed in neonates from mothers with AITD.

Conclusion. Children of mothers with raised levels of TPOab, have a transient hyperthyroxinemia one week after birth accompanied by a high frequency of hyperbilirubinemia suggesting that clinical examination and blood testing should be performed consecutively during the first postnatal week.

Keywords:

• Thyroid peroxidase antibody
• hyperthyroxinemia
• pregnancy
• neonate