A Discussion Of Normal Reference Interval Of Thyroid Function In The First Pregnant Trimester In Changsha City

Objective:The aim is to derive the normal reference interval of thyroid function in the first pregnant trimester of changsha cityMethods:we collected193women in the pregnant trimester (gestational age≤12weeks) and171healthy women of childbearing age over the same period in communities of Changsha; All subjects signed a consent form,voluntarily completed a questionnaire, and were collected fasting venous blood and morning urine;we determined anti-thyroid peroxidase antibody (TPOAb), anti-thyroglobulin antibodies (TGAb) antibody,thyroid stimulating hormone (TSH),free thyroid hormones (FT4),free thiiodothyronine(FT3), Total thyroxine(TT4), Total triiodothyronine(TT3)with method of chemiluminescence; we determined urinary iodine by the way of standardized arsenic cerium catalytic spectrophotometric.Results:Median concentrations of serum TSH level in normal early pregnant women was obviously declined compared with that in normal non-pregnant women (1.24[0.14-4.11] mIU/L vs2.24[0.76-5.80] mIU/L, P=.000); compared the median of serum FT4level in normal early pregnant women with that in normal non-pregnant women,the difference was no statistically significant(16.39[12.33-20.43] pmol/L vs16.03[12.68-20.36]pmol/L,P=0.973);the median of serum FT3level in normal early pregnant women was obviously declined compared with that in normal non-pregnant women (4.82[3.75-6.08] pmol/L vs5.23[4.32-6.19]pmol/L,P=.000), the median of serum TT4level in normal early pregnant women was obviously elevated compared with that in normal non-pregnant women(130.30[76.47-188.56] nmol/L vs111.25[77.94-150.60] nmol/L,P=.000); the median of serum TT3level in normal early pregnant women was elevated compared with that in normal non-pregnant women(2.17[1.57-3.09]nmol/L vs1.96[1.55-2.63] nmol/L,P=.000); According to different weeks in the first pregnant trimester, it showed that:the median of serum TSH level at7to12weeks of gestation was obviously declined compared with that at5to6weeks of gestation (1.18mIU/L vs2.04mIU/L, P=.007),but the median of serum TSH level at5to6weeks of gestation was no statistically significant compared with that in normal non-pregnant women (2.04mIU/L vs2.24mIU/L, P=.301), the median of serum TT4level at7to12weeks of gestation was obviously elevated compared with that at5to6weeks of gestation(137.50nmol/L vs110.20nmol/L,P=.001), but the median of serum TT4level at5to6weeks of gestation was no statistically significant compared with that in normal non-pregnant women (110.20nmol/L vs111.25nmol/L, P=.267), the median of free T4was not significantly altered in the first trimester.Conclusion:The study has derived the normal reference interval of thyroid function in the first pregnant trimester of changsha city, the TSH normal reference interval is0.14to4.11mIU/L, the FT4normal reference interval is12.33to20.43pmoL/L, the FT3normal reference interval is3.75to6.08pmoL/L.