评估妊娠早期甲状腺功能：中国妊娠妇女妊娠早期TSH参考上限的合理制定

Assessment of thyroid function during first-trimester pregnancy： What is the rational upper limit of serum TSH during the first trimester in Chinese pregnant women？

目的 为中国妊娠妇女妊娠早期亚临床甲状腺功能减退症（亚临床甲减）的诊断建立合理的TSH参考范围.方法 筛查4 800名妊娠4～12周妇女及2 000名非妊娠妇女甲状腺功能,对其中535名妊娠妇女进行妊娠中期及妊娠晚期随访.结果 血清TSH浓度中位数从妊娠7周开始出现显著降低.妊娠4～6周TSH的中位数显著高于7～12周[2.15（0.56～5.31）mIU/L对1.47（0.10～4.34） mIU/lL,P＜0.01],但与非妊娠妇女相比无明显差异[2.07（0.69～ 5.64） mIU/L,P=0.784].FT4中位数在妊娠早期无明显改变.以TSH＞2.5 mIU/L作为亚临床甲减的诊断标准,4 800名妊娠妇女的亚临床甲减患病率为27.8％,若采用本实验室所得的TSH参考范围（0.14～4.87 mIU/L）,该患病率仅为4％.在妊娠早期血清TSH＞2.5 mIU/L的118名妇女中,妊娠20周、30周时分别只有30.0％、20.3％的妊娠妇女TSH水平高于3.0 mIU/L.结论 非妊娠妇女的TSH参考范围适用于妊娠4～6周妇女亚临床甲减的诊断.中国妊娠妇女妊娠早期的TSddH水平上限显著高于2.5 mIU/L.

Objective To establish a rational reference range of serum TSH for diagnosis of subclinical hypothyroidism in the first trimester of pregnant women in China.Methods A total of 4 800 pregnant women in the first trimester and 2 000 women who planned to become pregnant were screened.535 pregnant women were evaluated in follow-up visits at the second and third trimesters.Results Median concentrations of serum TSH decreased significantly after the 7th week of gestation.The median of TSH during 4-6 weeks was significantly higher than that during7-12 weeks [2.15 （0.56-5.31） mIU/L vs 1.47 （0.10-4.34） mIU/L,P＜0.01],however,there was no significant difference compared with non-pregnant women [2.07 （0.69-5.64） mIU/L,P =0.784）.The median of FT4 was not significantly altered in the first trimester.The prevalence of subclinical hypothyroidism in the 4 800 pregnant women was 27.8％ with the diagnostic criterion of TSH＞2.5 mIU/L and 4.0％ by utilizing the reference range derived in our laboratory（0.14-4.87 mIU/L）.Additionally,out of 118 pregnant women who had serum TSH＞ 2.5 mIU/L in the first trimester,only 30.0％ and 20.3％ of them at the 20th and 30th week of gestation had TSH＞ 3.0 mIU/L.Conclusions The reference range for non-pregnant women can be used for the assessment of pregnant women during 4-6 weeks of gestation.The upper limit of serum TSH in the first trimester was much higher than 2.5 mIU/L in Chinese pregnant women.