Decreased T3 and T4 levels following topical application of povidone-iodine in premature neonates.

Thyroid function and iodine levels of 30 preterm neonates were examined before and up to five days after topical exposure to 10% povidone-iodine application. Urinary iodine excretion significantly increased in the group closest to term (8.9 +/- 1.2 mg I/g creatinine x 10) vs controls (3.5 +/- 0.5 mg; p < 0.01). T3 levels significantly decreased at all sub-group gestational ages vs controls (p < 0.01-0.05). Similarly, both FT4 and TT4 levels were lower in the subgroups vs controls (p < 0.01-0.05). TSH levels however did not rise in any group. These data suggest partial failure of thyroid hormone synthesis, in a population of high-risk infants possibly already exhibiting features of the euthyroid-sick syndrome. Topical iodine-containing antiseptic solutions should be used with caution in this population since these antiseptics may modify serum thyroid hormone concentrations rapidly.