The Comparison of Thyroxine versus Thyroxine plus Oral Iodine in the Treatment of Congenital Hypothyroidism due to Iodine Deficiency

AIM: Iodine deficiency is one of the most important causes of congenital hypothyroidism. In addition to thyroid hormone replacement, iodine supplementation is also given to newborns with congenital hypothyroidism due to iodine deficiency. We aimed to determine whether it is beneficial to administer iodine supplementation in addition to the L-thyroxine (L-T4) treatment of newborns with congenital hypothyroidism due to iodine deficiency. MATERIALS AND METHODS: Of 51 newborns, 26 who were diagnosed with congenital hypothyroidism due to iodine deficiency were treated with L-T4. The remaining 25 cases were given L-T4 plus 100 μg/day of oral iodine. Free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), thyroglobulin (TG), thyroid volume, urine iodine and breast milk iodine levels were measured in the first and third months of treatment, and the data were compared between the two groups. RESULTS: First- and third-month values of fT3, fT4, TSH, TG and thyroid volume for both groups were statistically similar. There was no significant difference between the two groups in respect to falling levels of fT3 and TSH, the rate of increase of fT4 levels or the shrinkage rate of thyroid volume. CONCLUSION: In this study, the addition of oral iodine to L-T4 treatment provided no benefit compared to treatment with L-T4 alone.