Analysis on iodine nutrition and thyroid levels of pregnant women with access to iodine supplement intervention in Xinjiang Uygur Autonomous Region

Objective To understand the pregnant women's nutritional status and thyroid hormone level difference after oral iodine oil supplement in areas at high-risk in southern Xinjiang and provide evidence for scientific iodine supplement. Methods A survey was conducted in Baicheng and Wushi counties where iodine supplement intervention had been carried out since 2015. In county,two villages were selected from each of two townships selected. In each village,15 pregnant women and 50 non-pregnant women aged 18-40 years were surveyed to test their urinary iodine and thyroid hormones levels. Results After the iodine supplement intervention,the median of urinary iodine levels in pregnant group and non-pregnant group were 181.73 μg/L and 228.35 μg/L respectively. In pregnant group,those whose urine iodine level <50 μg/L and <100 μg/L accounted for 5.83% and 16.66%,respectively. There were differences between the two groups in urine iodine level (χ²=6.470,P<0.05). The abnormal rate of serum free thyroxine (FT₄)was 16.76%,and those with the low rate accounted for 25.83% in pregnant group and 13.43% in non-pregnant group. The abnormal rate of thyroid stimulating hormone (TSH)was 22.35%. The difference in FT₃ and FT₄ abnormal rates between two groups had statistical significance (t=15.027,t=9.070,P<0.05),the difference in TSH abnormal rate between two groups had no statistical significance (t=0.380,P>0.05). The incidence of hypothyroidism was 3.33% and the incidence of subclinical hypothyroidism was 10.00% in pregnant group. In non-pregnant group,the incidence of hyperthyroidism was 0.72%,the incidence of hypothyroidism was 5.04% and the incidence of subclinical hypothyroidism was 17.98%. There was significant difference in incidence of hypothyroidism between two groups (χ²=4.380,P<0.05). Conclusion After the intervention of iodine supplement,the iodine nutrition level of the pregnant women was in a suitable range. Subclinical hypothyroidism was the main form of abnormal thyroid function,which might be the common type of thyroid dysfunction in this area. TSH, FT₃, FT₄ detections were important for the early diagnosis, treatment and prevention of abnormal thyroid function.