Abstract:

Objective To establish the reference ranges of thyroid function determination for pregnant women during the 1st and 2nd trimesters in Guangdong General Hospital. Methods A total of 279 pregnant women with singleton pregnancy,including 147 women during the 1st trimester pregnancy and 132 women during the 2nd trimester pregnancy,were screened according to the National Academy of Clinical Biochemistry （NACB） recommendations and clinical criteria. The levels of free triiodothyronine（FT₃）,free thyroxine（FT₄） and thyroid stimulating hormone（TSH） were determined by chemiluminescence immunoassay. The trimester-specific reference ranges were established,according to the national health industry standard WS/T402 . Results The reference ranges of FT₃ calculated by median（M） and two-sided limits（P_2.5 and P_97.5） were 3.48-5.20 pmol/L at the 1st trimester and 3.26-5.46 pmol/L at the 2nd trimester,the reference ranges of FT₄ were 8.05-14.86 pmol/L and 7.09-12.12 pmol/L,and the reference ranges of TSH were 0.10-2.98 mIU/L and 0.05-2.48 mIU/L,respectively. The validation of these reference ranges was passed. Compared with non-pregnant control women,FT₃,FT₄ and TSH of pregnant women during the 1st and 2nd trimesters had statistical significance,except FT₄ during the 1st trimester（P<0.05）. Conclusions For the judgement and diagnosis for pregnant women's thyroid function,it is necessary for hospitals to establish the reference ranges for thyroid function determination.

Key words: Thyroid hormone, Pregnancy, Reference range