Relationship between thyroid function, iodine nutrition and autoantibodies in pregnant women / 中华地方病学杂志

ABSTRACT

Objective:To analyze the relationship between thyroid function, iodine nutrition level and thyroid autoantibodies in pregnant women.Methods:In 2016, pregnant women were selected from different water iodine areas in Tianjin. A disposable urine sample of 25 ml was collected to determine urine iodine, and 3 ml of intravenous non-anticoagulated blood was collected to determine serum thyroid hormones and thyroid autoantibodies. Chemiluminescence immunoassay was used to determine the thyroid function indexes [free triiodothyronine (FT 3), free thyroxine (FT 4), thyroid-stimulating hormone (TSH)], thyroid peroxidase antibody(TPOAb) and thyroglobulin antibody (TgAb) levels in pregnant women. According to serum TSH and FT 4 levels, pregnant women were divided into the euthyroidism group and subclinical hypothyroidism group(referred to as hypothyroidism). Urine iodine arsenic-cerium catalytic spectrophotometry was used to detect the urine iodine level of pregnant women. The correlation between urinary iodine levels and thyroid function indexes of the two groups of pregnant women was analyzed, and single factor and multivariate logistic regression were used to analyze the influencing factors of hypothyroidism. Results:There were 798 pregnant women in the euthyroidism group and 28 pregnant women in the hypothyroidism group. The hypothyroidism detection rate was 3.39% (28/826). In the euthyroidism group and hypothyroidism group, 43.73% (349/798) and 46.43% (13/28) of pregnant women had urine iodine levels < 150 μg/L, respectively. There was no correlation between urine iodine level and serum TSH ( r = 0.038, P > 0.05), and a positive correlation with serum FT 4 ( r = 0.077, P < 0.05). The differences between the euthyroidism group and the hypothyroidism group in the median (interquartile range) of TPOAb and TgAb were statistically significant ( Z = - 3.986, - 3.411, P < 0.05). After logistic regression analysis, TPOAb was a risk factor for hypothyroidism ( OR = 3.428, 95% CI: 1.131 - 10.388). Conclusions:Urine iodine and thyroid autoantibodies should be screened as routine examination items before or during pregnancy. Correct iodine deficiency in time, avoid blindly excessive iodine supplement, and reduce the occurrence of subclinical hypothyroidism in pregnant women, so as to reduce the adverse effects on mothers and their offspring.