Dynamic changes of thyroid hormone levels in pregnant women in previous iodine deficiency regions of Xinjiang Uygur Autonomous Region / 中华地方病学杂志

ABSTRACT

Objective:To observe the dynamic changes of thyroid hormone levels and thyroid autoimmune antibodies in pregnant women in Xinjiang Uygur Autonomous Region during pregnancy, and to investigate the significance of repeated screening of thyroid function in different gestational ages.Methods:A retrospective study was carried out of pregnant women who completed thyroid function screening in Clinic, People's Hospital of Xinjiang Uygur Autonomous Region from January 2015 to December 2017, and the test results of thyroid stimulating hormone (TSH), free thyroxine (FT 4), free triiodothyronine (FT 3), thyroid peroxidase antibody (TPOAb), and anti-thyroglobulin antibody (TGAb) were collected and analyzed of their changes during pregnancy. Pregnant women were divided into 2 different gestational age groups by the age limit of 30, the changes of thyroid dysfunction rate with pregnancy were analyzed, and the clinical significance of repeated screening in different pregnancy stages was discussed. Results:Changes of thyroid-related indicators with pregnancy first, second, and third trimesters were 404,725, and 767 cases, respectively; TSH level in the third trimester (2.76 mU/L) was significantly higher than those in the first and second trimesters (2.55, 2.36 mU/L, P < 0.05), there was no significant difference between the first trimester and the second trimester ( P > 0.05); the FT 4 and FT 3 levels decreased gradually with pregnancy ( P < 0.05); the positive rate of TPOAb was significantly higher in the first and second trimesters than that in the third trimester ( P < 0.05), there was no significant difference between the first trimester and the second trimester ( P > 0.05); the positive rate of TGAb decreased gradually with pregnancy ( P < 0.05). Comparison of abnormal rate of TSH in different gestational ages the first, second, and third trimesters were 352, 664, 735 cases, respectively; the abnormal rate of TSH in the overall study was statistically significant at different stages of pregnancy (χ 2=31.627, P < 0.05), the first trimester was significantly higher those in the second and third trimesters ( P < 0.05). In pregnant women aged ≥30 years old, the abnormal rate of TSH in the first trimester was significantly higher than those in the second and third trimesters ( P < 0.05); in pregnant women aged < 30 years old, the abnormal rate of TSH in the first trimester was significantly higher than that in the third trimester ( P < 0.05). There were no significant differences in the abnormal rate of TSH in the first, second, and third trimesters between the < 30 years old group and ≥30 years old group ( P > 0.05). Comparison of abnormal rate of FT 4 in different gestational ages there were no significant differences in the FT 4 abnormal rate among different pregnancy groups in the overall, < 30, ≥30 years old groups (P > 0.05). In early pregnancy, the abnormal rate of FT 4 in the ≥30 years old group was higher than that in the < 30 years old group ( P < 0.05); in second and third trimesters, there were no significant differences between the two age groups ( P > 0.05). Conclusions:Screening for thyroid function in the first trimester of pregnancy is important for women of different ages. Except for women with abnormal thyroid function who have not been treated during the first trimester, the rest may not need to be screened again. Pregnant women aged ≥30 years old may have a higher risk of thyroid dysfunction than those < 30 years old.