Investigation on iodine nutrition and thyroid function of pregnant women in Hubei Province in 2020 / 中华地方病学杂志

ABSTRACT

Objective:To investigate the iodine nutrition level and thyroid function status of pregnant women in Hubei Province.Methods:According to the requirements of "the National Iodine Deficiency Disorders Monitoring Program (2016 Edition)", in 2020, using a cross-sectional survey method, two mountainous counties and two plain areas in Hubei Province were divided into five districts east, west, south, north, and central. One township (street) was selected from each district, and 20 pregnant women were selected from each township (street) as survey subjects. Urine iodine content and thyroid function indicators [serum free triiodothyronine (FT 3), free thyroxine (FT 4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb)] were tested. Abnormal thyroid function rate and antibody positive rate were analyzed, and correlation analysis of thyroid function indicators was conducted (Spearman method). Results:A total of 321 pregnant women were included, including 43, 114, and 164 in early, middle, and late pregnancy, respectively; The median urinary iodine was 164.80 μg/L. The median serum FT 3, FT 4, TSH, TPOAb, TgAb levels were 4.10, 12.83 pmol/L, 1.85 mU/L, 15.84 and 13.35 U/ml, respectively. There were statistically significant differences in FT 3, FT 4, and TSH levels among different trimesters ( P < 0.05). According to Spearman's correlation analysis, FT 3 in early stage of pregnancy was negatively correlated with TSH and TPOAb levels ( r = - 0.46, - 0.33, P < 0.05), while TSH was positively correlated with TPOAb level ( r = 0.33, P = 0.032); there was a positive correlation between FT 4 and TgAb levels in middle stage of pregnancy ( r = 0.21, P = 0.032); there was a negative correlation between FT 3 and TPOAb levels in late stage of pregnancy ( r = - 0.19, P = 0.017); FT 3 and FT 4, TPOAb and TgAb levels were positively correlated throughout pregnancy ( P < 0.05). There was no correlation between urinary iodine content and thyroid function indicators ( P > 0.05). The total abnormal rate of thyroid function was 7.79% (25/321), with 16.28% (7/43), 5.26% (6/114), and 7.32% (12/164) in early, middle, and late pregnancy, respectively. There was no statistically significant difference in the abnormal rate of thyroid function among different pregnancy periods (χ 2 = 4.83, P = 0.097). The detection rates of hypothyroxinemia, hypothyroidism, subclinical hypothyroidism, hyperthyroidism, and subclinical hyperthyroidism were 4.36% (14/321), 0.31% (1/321), 2.49% (8/321), 0.31% (1/321), and 0.31% (1/321), respectively. The positive detection rate of autospecific antibodies was 10.28% (33/321), with a TPOAb positive detection rate of 9.97% (32/321) and a TgAb positive detection rate of 5.30% (17/321). Conclusions:The iodine nutrition level of pregnant women in Hubei Province is at a suitable level, and the rates of abnormal thyroid function and thyroid autospecific antibody positive are relatively low. It is necessary to continuously monitor the iodine nutrition and thyroid function indexes of pregnant women, strengthen health education on the hazards of iodine deficiency during pregnancy, and minimize the harm to maternal and infant health caused by iodine deficiency.