[Prevalence of postpartum thyroiditis in three different iodine intake areas]

To investigate the prevalence of postpartum thyroiditis (PPT) in three different iodine intake areas, to explore the relationship between iodine intake and PPT.

Panshan, Zhangwu and Huanghua are three different iodine intake areas. The median urinary iodine concentration were 103 micro g/L, 374 micro g/L and 614 micro g/L, respectively. One hundred and nineteen lactational women were investigated during the first year postpartum. Thyroid stimulating hormone (TSH), free thyroxine (FT(4)), free triiodothyronine (FT(3)), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) were determined with immulite method, and UI was determined by As-Ce(4+) catalytic spectrophotometry method.

The prevalence of PPT is 11.8%, 10.1% of subclinical PPT, whereas 1.7% of clinical PPT. There was statistically significant difference in the frequency of PPT in three areas (Panshan 5.6%, Zhangwu 23.1% and Huanghua 6.8%, P < 0.05), but no difference in the frequency of thyroid autoimmune antibody (TAA). 50% of positive TAA women developed into PPT.

Higher prevalence of subclinical PPT was found in the area with moderate iodine deficiency after iodine supplementation, suggesting a possible role of iodine supplementation in PPT.