Study of the Effect of Iodized Oil Supplementation During Infancy

In iodine-deficient countries or regions that have inadequate iodized salt distribution, the World Health Organization (WHO) recommends choosing one of two methods to improve iodine intakes in breastfeeding infants: 1) iodine supplement (400 mg as iodized oil; 1/year) to the breastfeeding mother, or 2) iodine supplement (100 mg as iodized oil; 1/year) directly to the infant. However, the relative efficacy of these two methods of providing iodine to the newborn has never been directly compared. Whether the first method of iodine supplementation to the breast feeding mother can significantly improve iodine supply and maintain normal thyroid function in her infant remains unclear. This study will directly compare these two strategies. The hypothesis is that the two strategies will be equally effective in providing iodine to the newborn.