title: Development of gestation-specific reference intervals for thyroid hormones in normal pregnant Northeast Chinese women: What is the rational division of gestation stages for establishing reference intervals for pregnancy women?
abstract: BACKGROUND
  A laboratory- and region-specific trimester-related reference interval for thyroid hormone assessment of pregnant women was recommended. Whether the division by trimester is suitable requires verification. Here, we tried to establish appropriate reference intervals of thyroid-related hormones and antibodies for normal pregnant women in Northeast China.
  
  
  METHODS
  A total of 947 pregnant women who underwent routine prenatal care were grouped via two methods. The first method entailed division by trimester: stages T1, T2, and T3. The second method entailed dividing T1, T2, and T3 stages into two stages each: T1-1, T1-2, T2-1, T2-2, T3-1, and T3-2. Serum levels of TSH, FT3, FT4, Anti-TPO, and Anti-TG were measured by three detection systems.
  
  
  RESULTS
  No significant differences were found in TSH values between T1-1 group and the non-pregnant women group. However, the TSH value of the T1-1 group was significantly higher than that of T1-2 group (P<0.05). The TSH values in stage T3-2 increased significantly compared to those in stage T3-1 measured by three different assays (P<0.05). FT4 and FT3 values decreased significantly in the T2-1 and T2-2 stages compared to the previous stage (P<0.05). The serum levels of Anti-TPO and Anti-TG were not having significant differences between the six stages.
  
  
  CONCLUSIONS
  The diagnosis and treatment of thyroid dysfunction during pregnancy should base on pregnancy- and method-specific reference intervals. More detailed staging is required to assess the thyroid function of pregnant women before 20 gestational weeks.
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Clinical Laboratory, The 1st Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Xia
authors.affiliation: Department of Clinical Laboratory, The 2nd Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Cai
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Guixue
authors.initials: G
authors.lastname: Cheng
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Mengyuan
authors.initials: M
authors.lastname: Sheng
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China. Electronic address: qinxs@sj-hospital.org.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Qin
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011264:Pregnancy Trimesters / Q000097:blood*; D012016:Reference Values; D013959:Thyroid Diseases / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000378:metabolism; D013963:Thyroid Hormones / Q000097:blood / Q000592:standards*; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*; D055815:Young Adult
chemical_list: D013963:Thyroid Hormones; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine
keywords: Pregnancy; Reference interval; Thyroid hormones