ABSTRACT
BACKGROUND: Excessive iodine intake increases the occurrence of autoimmune thyroid disorders by enhancing immunogenecity of iodine-rich thyroglobulin, In Korea, most of postpartum women take a large amount of iodine-rich seaweed. Although the excessive iodine intake may affect the thyroid function, only a few reports were available concering iodine intake, especially on postpartum period. METHODS: A prospective study was undertaken in 146 of normal delivered postpartum women. Dietary intake and urinary excretion of iodine, serum T3, T4, TSH, anti-TPO Ab and anti-Tg Ab were measured before and 1, 6, 12 and 24 weeks after delivery. Iodine intake was analyzed by one-to-one interview using 24hr recall and food frequency questionnaire. RESULTS: 1. PPT was occurred in 6 (10.3%) postparturn women, It presented as hypothyroidism alone in 1 (16.7%), transient thyrotoxicosis followed by hypothyroidisrn in 3 (50.0%), and thyrotoxicosis alone in 2 (33.3%) of the follwed-up patients. 2. During pregnancy, no difference was found in age, serum T3, T4 and TSH between PPT and normal thyroid function group. 3. In PPT group, anti-TPO and anti-Tg Ab were significantly higher than those of normal thyroid function group during pregnancy, and their sensitivity for PPT was 40% and 33%, respectively. But there was no correlation between dietary iodine intake and the titer of thyroid auto-antibodies. 4. There was no correlation between pre and post-partum dietary iodine intake and occurrence of PPT. CONCLUSION: In Korea, the incidence of PPT was slightly higher than other nations. The sensitivity of thyroid auto-antibodies was too low to use for prediction of PPT. Pre and post-partum iodine intake had no effect on the occurrence of PPT and post-partum thyroid function.