ROUTINE SKIN CLEANSING WITH POVIDONE-IODINE IS NOT A COMMON-CAUSE OF TRANSIENT NEONATAL-HYPOTHYROIDISM IN NORTH-AMERICA - A PROSPECTIVE CONTROLLED-STUDY

A high incidence of transient neonatal hypothyroidism has been observe d in premature infants after routine skin cleansing with iodine. Becau se these reports have been predominantly from Europe, a borderline, io dine-deficient area, we wished to determine whether this was also true in North America, an iodine-sufficient area. A prospective, controlle d study was performed in premature babies less than or equal to 36 wee ks gestation admitted to a neonatal intensive care nursery. Thyroxine (T-4) and thyrotropin (TSH) were measured at day 1, days 4 to 6, and 1 0 to 12 after skin preparation with iodine or with a noniodine-contain ing antiseptic solution (chlorhexidine) that served as control. If rep eat cleansing was required, this sequence was repeated. Urinary iodine was quantitated on days 1 to 3 to estimate iodine exposure. There was no difference in the mean T-4 concentration at any of the time points evaluated nor in the incidence of transient hypothyroidism between th e iodine-exposed (2/17) and control babies (0/14) despite urinary iodi ne excretion up to 88 times the control value. Unexpectedly 5 iodine-e xposed but 0 control babies developed severe hypothyroxinemia (T-4 < 4 0 mmol/L), compatible with the sick euthyroid syndrome; one of them di ed. We conclude that, unlike in Europe, transient hypothyroidism is no t a common sequela of routine skin cleansing with iodine in premature newborn infants in North America. This difference in incidence may be due to prior iodine status. Whether excessive iodine absorption in pre mature infants is associated with thyroid-independent toxic effects re mains to be clarified.