Effect of iodine loading on the thyroid hormone level of newborns living in Kayseri province.

INTRODUCTION

Excessive iodine exposure during the fetal and neonatal periods can lead to neonatal hypothyroidism. This study was conducted to evaluate the level of iodine loading among newborns living in Kayseri province. A total of 59 newborns, who were admitted due to disorders in thyroid hormone levels, were included in the study. Materials and

METHODS

Among the patients who applied with thyroid hormone dysfunction, newborns with a spot urine iodine level ≥ 20 μg/dL were included in the study between the years 2003 and 2013. Free T3 (fT3), free T4 (fT4), thyroid stimulating hormone (TSH), thyroglobulin (Tg), breast milk iodine, thyroid ultrasonography, and control measurements of fT3, fT4, TSH, and Tg levels were obtained accordingly from both groups of patients who received or did not receive treatment.

RESULTS

The average age of the patients was 15 days with a 36/23 girl to boy ratio. Statistically, no significant difference was noticed between all the girls and boys with respect to all the measured values. The etiologic search showed that out of 59 cases, in 18 cases (30.5%) only the mother and in 19 cases only the newborns (32.2%) had a history of povidone iodine exposure; in 8 cases both mothers and their babies had exposure to povidone iodine (13.6%). In 14 cases (23.7%), the source of iodine loading could not be determined. Levothyroxine (L-thyroxine) treatment was initiated in 56% of the patients (n = 33). Out of 33 patients who were under treatment with L-thyroxine, in 13 cases only the mother had history of povidone iodine exposure; in 12 cases, only the baby had a history of povidone iodine exposure; in 1 case, both mother and her baby had a history of povidone iodine exposure, but the etiology could not be found in 7 cases.

CONCLUSION

The use of antiseptics-containing iodine for mothers before and after birth and for newborns, especially for umbilical cleansing, can lead to iodine loading and hypothyroidism. If transient hypothyroidism develops within this period, then it may not be detected promptly. This can later lead to retardation in psychomotor development and disorder in learning skills during the childhood period.