Gestational Changes Of Serum Thyroid Hormone Levels

Objective:To investigate the pregnancy early,middle and late stages of serum thyroid hormone level changes.Analysis of normal pregnant women pituitary thyroid axis functional changes.Methods:The subjects were divided into Normal control group:the health of 40 cases of non-pregnant female,age 22-35 years old;the observation group:145 cases of pregnant women,aged 22-35 years old,one of the early pregnancy(12weeks)32cases, middle pregnancy(13-27weeks)65cases,late pregnancy(28-40weeks) 48 cases.Appeal to observe the object of women of childbearing age are healthy,without previous thyroid disease and other diseases history,by thyroid ultrasound examination to exclude B block and thyroid nodules.Separately to collect the normal control group of women and early,middle and late phases of the blood samples of pregnant women,using radioimmunoassay(RIA) were used to detect serum levels of thyroid hormone:serum total triiodothyronine(TT₃),serum total thyroxine(TT₄),three serum free triiodothyronine(FT₃),serum free thyroxine(FT₄);using sandwich immunoradiometric assay(IRMA) for determination of serum thyroid stimulating hormone(TSH) levels, The results were analyzed statistically.Results:(1) pregnancy maternal serum TT₃,TT₄ content than those in the normal control group was significantly higher,and with the extension of pregnancy serum TT₃,TT₄ increased more significantly(P＜0.01).(2) FT₃ serum level in early pregnancy and second trimester of pregnancy higher, and decline in third trimester of pregnancy;FT₄ serum higher in early pregnancy, medium-and third trimester of pregnancy declining gradually.During early pregnancy FT₃,FT₄ level within the normal range,late pregnancy FT₃ approximately 6.25%,FT₄ about 10.42%lower than normal.(3) TSH serum levels in early pregnancy minimum,and about 28.13%lower than normal;pregnancy advanced gradually picked up,and were within the normal range.(4) pregnancy TT₄ serum levels exceeding the normal range of the ratio of early pregnancy to 31.25%,43.08%for the second trimester,third trimester to 56.25%; pregnancy serum TT₃ levels exceeding the normal range of ratios,significantly lower than TT₄,during early pregnancy of up to 3.13%,4.62%for the second trimester,third trimester of pregnancy to 6.25 percent.Conclusion:changes in thyroid function during pregnancy and is closely related to detection of thyroid hormone during pregnancy has an important significance.Serum TT₃,TT₄ levels in pregnancy than those in the control group significantly increased.,increase the high trend more Obvious with pregnancy extension;pregnancy early-term serum FT₃,FT₄ level is relatively high,and then gradually declined;TSH serum levels in early pregnancy minimum,then gradually increased.