Abstract: Objective To evaluate thyroid function of pregnant women and neurocognitive development of their offspring after continuous iodine supplementation in Aksu of Xinjiang, and to provide the basis for further research. Methods This study included 35 non-pregnancies (non-pregnant group) and 165 pregnant women (pregnant group). There were 5 pregnant cases did not take the detection of SH and TH due to the loss of follow-up. Pregnant group was subdivided into three groups including pregnancy week 0- 13 (early stage group), pregnancy week 14- 27 (middle stage group) and pregnancy week 28- 40 (late stage group). The random urine samples of early morning and venous blood samples were collected in two groups to determine the urinary iodine concentration by the arsenic cerium catalytic spectrophotometry, and thyroid hormone levels (TSH, FT4, FT3, TT4, and TT3 were detected by immunochemiluminometric assay. Offsprings of pregnant group were followed up two years. Gesell scale was used to assess their neurocognitive function. Results The total MUIC of pregnant women was 196.7 (122.9,269.2) μg/L. There were 52 cases in pregnant group (32.5%) and 108 in nonpregnant group (67.5%) with total UIC ≤150 μg/L and ＞150 μg/L. The FT3 level was lower and TT4 and TT3 levels wereincreased at the early stage of pregnancy in pregnant group compared with those of non-pregnant group. FT4 and FT3 levels were decreased and TT4 and TT3 levels increased in the middle stage group and late stage group (P<0.05). FT3 level was higher at the early stage group than that of middle stage group and late stage group (P<0.05). There were no significant differences in the other indicators between three groups. The abnormal rates of thyroid were 8.75% (14/160) in pregnant group, of which 5.63% cases were subclinical hypothyroidism (9/160), 3.13% were Tg- Ab + (5/160). There was no overlapping cases between subclinical hypothyroidism and Tg-Ab+ cases. There were no patients with overt hypothyroidism, hyperthyroidism and hypothyroxinemia in pregnant group. The offsprings of uygur pregnant women in this tracing study showed a lower language quotient score, and abnormal rate of Gesell was 3.75% (3/80), and the suspicious rate was 12.50% (10/80), normal rate was 83.75% (67/80). Conclusion After two years or more of family eligible iodized salt consumption come to qualified， the pregnant women in township of Aksu show adequate iodine nutrition with no overt abnormality of thyroid function, which can be considered as a group of control group for the subsequent research.

Key words: pregnancy, infant, XINJIANG, Uygur Nationality, thyroid hormones, reference values, iodine deficiency