Iodine status and thyroid function of pregnant, lactating women and infants (0-1 yr) residing in areas with an effective Universal Salt Iodization program

Objective: To assess the iodine nutrition and thyroid function of pregnant women, lactating women and infants residing in areas where the Universal Salt Iodization program is in place. Methods: Pregnant women, lactating women and infants were selected randomly in the regions where iodized salt coverage rate is more than 90% since 2000. Urine iodine levels of pregnant woman, lactating woman and infants, milk iodine of lactating woman, thyroid-stimulating hormone (TSH) and free T4 of women were tested respectively. Results: Median Urinary Iodine (MUI) of infants, three groups of pregnant women (first, second and third trimester) and two groups lactating women (breastfeeding less than or more than six months) were 233, 174, 180, 147, 126 and 145 mu g/L, respectively. Median milk iodine of lactating women was 163 mu g/L. Percentage of milk iodine < 150 mu g/L of early lactating women was 40% less than that of late lactating women (p < 0.01). There was a positive correlation between urine iodine of infants and milk iodine of lactating women (r = 0.526, p = 0.000). T4 of two women were above or below the reference range. Total 15.4% women's TSH were abnormal. Most of these women's urinary iodine were lower than 150 mu g/L. Conclusion: Iodine status of most of the target population for Universal Salt Iodization program is adequate, but iodine deficiency still existed in some. To assure every new life's brain not be damaged by iodine deficiency, iodine status of targeted populations should be monitored and supplements provided according to the monitoring outcomes.