Background: Transient thyroid dysfunction with its adverse effects of diminished levels of thyroid hormone on mental development has been reported in neonates whose skin has been cleaned with iodine-containing substances. We report the results of thyroid screening in iodine-exposed neonates and controls.
Population and methods: Thirty seven neonates admitted to an intensive care unit from 1990 to 1992 and whose medical condition required umbilical catheterization were included in the study. There were 21 neonates (six term and 15 preterm) for whom the area around the umbilicus was cleansed with iodine antiseptic and 16 controls (four term and 12 preterm) for whom the antiseptic used did not contain iodine. Levels of serum free T3 and T4, and TSH were determined by 7 days after catheterization as did urinary iodine and creatinine concentrations.
Results: Iodine-exposed neonates had significant high levels of TSH (P < 0.01) and low free T3 (P < 0.05); levels of free T4 were lower than in controls but not significantly. Urinary iodine excretion was significantly increased. The increase in TSH disappeared between 15 and 30 days after iodine application.
Conclusion: Application of iodine antiseptics may cause transient thyroid dysfunction in neonates leading to propose the use of non iodinated substances with similar antibacterial efficacy.