Iodine is an essential component of thyroid hormone, which is necessary for many metabolic processes as well as the maturation of the CNS. Deficiencies of iodine have deleterious effects on both pregnant women and infants. The iodine status of the population after implementation of the universal salt iodization program in Zhejiang province has not been known. This study was to determine whether pregnant women show evidence of iodine deficiency, and to examine the correlation between maternal urine iodine concentration and newborn thyroid function.