目的 建立北京地区健康妊娠妇女不同妊娠时期的血清甲状腺激素水平的正常参考范围，为正确评价孕期甲状腺功能和诊断甲状腺疾病提供了依据。方法 按照美国国家临床生化研究院(NACB)的标准,随机选择20～35 岁健康妊娠期妇女360名作为研究组，并按孕周分为妊娠早、中、晚期，同时随机选取符合标准的非妊娠健康妇女 135 名作为对照组，检测比较三碘甲状腺素(T3)、甲状腺素(T4)、游离三碘甲状腺素(FT3)、游离甲状腺素（FT4）、促甲状腺激素(TSH )的水平。结果 妊娠期妇女甲状腺激素水平与非妊娠期妇女多组比较差异有统计学意义（P<0.01）。非妊娠期妇女血清各项检测指标的参考范围分别为：TT3：1.26～2.07 nmol/L，TT4：83.34～136.21 nmol/L，FT3：4.27～6.29 pmol/L，FT4：9.35～15.23 pmol/L，TSH：0.60～5.99 uIU/mL。妊娠期妇女血清TT3水平在妊娠早、中、晚期的参考范围分别为：1.54～2.91 nmol/L、1.48～2.85 nmol/L、1.48～2.65 nmol/L ；血清TT4水平在妊娠早、中、晚期的参考范围分别为：96.74～178.53 nmol/L、84.44～172.07 nmol/L、84.60～151.29 nmol/L；血清FT3水平在妊娠早、中、晚期的参考范围分别为：3.86～5.81pmol/L、3.57～5.54pmol/L、 3.47～5.13pmol/L；血清FT4水平在妊娠早、中、晚期的参考范围分别为：6.87～14.42pmol/L、6.27～10.86pmol/L、6.63～11.05pmol/L；血清TSH 在妊娠早、中、晚期参考范围分别为：0.60～3.98μIU/mL、0.22～4.69 μIU/mL、0.44～5.02 μIU/mL。结论 妊娠期妇女血清甲状腺激素水平与非妊娠期妇女存在明显差异，且妊娠各期之间亦存在明显差异。因此，目前临床上通常应用非孕期甲状腺检测的参考范围评价孕期甲状腺功能是不正确的，建立北京地区妊娠期妇女甲状腺激素参考范围具有重要意义。

Objective To establish the trimester-specific reference ranges of thyroid hormone for normal pregnant women, and to provide clinical evidence for early diagnosis and treatment of thyroid disease in pregnancy. Method Inclusion criteria were established according to the National Academy of Clinical Biochemistry (NACB) recommended standard, 360 healthy pregnant women whose age are between 20 and 35 were selected as the study group, and were divided into three groups according to gestational ages, 135 healthy non pregnant women were chosen as the control group. The serum levels of T3, T4, FT3, FT4 and TSH in all groups were detected. Results The thyroid hormone levels between different pregnancy stages had statistical significance compared with non pregnancy groups (P< 0.01). The reference ranges of thyroid hormones in non pregnant women were as follows TT3：1.26–2.07 nmol/L，TT4：83.34–136.21 nmol/L，FT3：4.27–6.29 pmol/L，FT4：9.35–15.23 pmol/L，TSH：0.60–5.99 μIU/mL. In the 1st、2nd and 3rd trimester pregnancy, the serum TT3 reference values were 1.54–2.91 nmol/L, 1.48–2.85 nmol/L and 1.48–2.65 nmol/L respectively; the TT4 reference values were 96.74–178.53 nmol/L, 84.44–172.07 nmol/L and 84.60–151.29 nmol/L; the FT3 reference values were 3.86–5.81pmol/L, 3.57–5.54pmol/L, 3.47–5.13pmol/L; the FT4 reference values were 6.87–14.42pmol/L, 6.27–10.86pmol/L, 6.63–11.05pmol/L; the serum TSH reference values were 0.60–3.98μIU/mL, 0.22–4.69 μIU/mL and 0.44–5.02 μIU/mL. Conclusion There are significant differences in the thyroid hormone levels between pregnancy and non pregnancy, and significant differences also exist between different stages of pregnancy, thus to establish trimester-specific reference values of thyroid hormones during normal pregnancy must be meaningful for clinical practice.