Adverse effect of iodide containing contrast agents on newborn thyroid function

Abstract

Administration of iodine containing antiseptic agents during perinatal life is known as the most frequent reason for transient hypothyroidism in newborns. Since we have detected one newborn infant who developed transient hypothyroidism after angiocardiography(ACG), we investigated thyroid function in 30 babies with congenital heart disease before and after ACG. Informed consent was given by the parents. RESULTS: After ACG with 20 ml diatrizoate 76%(iodide content 200-400 ug) 6 newborns developed transient hypothyroidism within 5 days. In 3 of them renal function was reduced for a few days. Thyroid function returned to normal within 2 weeks in 4 newborns and after 2 weeks in 2 infants. All infants with transient hypothyroidism were less than 4 weeks of age.Infants older than 4 weeks did not develop hypothyroidism, but showed a slight increase of their T4- and T3-serum concentrations 2 to 4 weeks after ACG. CONCLUSION: Newborn infants develop transient hypothyroidism after ACG in more than 80%.Even the administration of relatively small doses of iodide may be followed by an acute Wolff-Chaikoff-Effect. This may be due to immaturity of thyroid autoregulative function.