Objective: To analyze the influence of different thyroid stimulating hormone (TSH) cut-offs to diagnose subclinical hypothyroidism (SCH) in the first trimester of gestation. Methods: A total of 896 pregnant women were enrolled in Peking University International Hospital between October 2016 and March 2018. Among them, 421 pregnant women with single fetus who were conformed to the criteria of National Academy of Clinical Biochemistry (NACB), without adverse pregnancy outcomes and obstetric complications, were selected to establish their self-sequential longitudinal reference ranges of thyroid function. Then, SCH was diagnosed in the first trimester, using different TSH cutoffs, such as the upper limit of the first trimester-specific reference range, 4.0 mU/L recommended by the 2017 Guidelines of American Thyroid Association (ATA), 5.17 mU/L (Roche reagent) recommended by 2012 Guidelines of Chinese Society of Endocrinology and Chinese Society of Perinatal Medicine, and 2.5 mU/L recommended by 2011 Guidelines of ATA, respectively. Results: The TSH reference range was 0.12-4.16 mU/L in the first trimester. Using TSH>4.16, 4.0, 5.17 and 2.5 mU/L to diagnose SCH in the first trimester, the prevalence rates were 4.35% (39/896), 5.92% (53/896), 1.56% (14/896) and 20.87% (187/896), respectively. There was no statistically significant difference between the prevalence rates of SCH using the TSH upper reference limit of 4.0 mU/L and 4.16 mU/L (P=0.134). When TSH was defined as>4.0 mU/L to diagnose SCH, the sensitivity, specificity and Youden index was 97.4%, 98.2%, and 0.956, respectively. Conclusions: The TSH upper reference limit of 4.0 mU/L recommended by 2017 Guidelines of ATA can be used as a cut-off to diagnose SCH in first trimester for the areas without trimester-specific reference ranges for TSH in China.
目的： 分析妊娠早期采用不同促甲状腺激素（TSH）切点值诊断亚临床甲状腺功能减退症（SCH）的患病情况。 方法： 顺序纳入北京大学国际医院2016年10月至2018年3月建档的妊娠妇女896名，筛选上述人群中符合美国临床生化研究院推荐标准，且为单胎妊娠、无不良产科结局及妊娠并发症的孕妇421名，年龄（31.0±3.9）岁，采用自我纵向序列研究方法建立妊娠期特异性甲状腺功能参考值范围。妊娠早期特异性TSH参考值范围上限分别采用2017年美国甲状腺协会（ATA）妊娠和产后甲状腺疾病诊治指南推荐的4.0 mU/L，2012年中国妊娠和产后甲状腺疾病诊治指南推荐的5.17 mU/L（Roche试剂）及2011年ATA妊娠和产后甲状腺疾病诊治指南推荐的2.5 mU/L，诊断妊娠早期SCH的患病率。 结果： 本研究妊娠早期特异性TSH参考值范围为0.12~4.16 mU/L。分别采用TSH>4.16、4.0、5.17、2.5 mU/L诊断妊娠早期SCH，其患病率分别为4.35%（39/896）、5.92%（53/896）、1.56%（14/896）、20.87%（187/896）。其中以TSH>4.0 mU/L及TSH>4.16 mU/L作为诊断切点值时，妊娠早期SCH的患病率差异无统计学意义（P=0.134）。妊娠早期以TSH 4.0 mU/L为切点值诊断SCH的灵敏度、特异度分别为97.4%、98.2%，Youden指数0.956。 结论： 2017年ATA指南推荐的TSH 4.0 mU/L，可作为未建立妊娠特异性甲状腺功能参考值范围地区诊断妊娠早期SCH的切点值。.
Keywords: Pregnancy; Subclinical hypothyroidism; Thyrotropin.