title: [Reference interval in preliminary investigation of maternal thyroid function during pregnancy in Shenzhen China].
abstract: OBJECTIVE
  To explore the thyroid function distribution of different trimesters among normal pregnant women and establish the reference interval for maternal thyroid function during pregnancy in Shenzhen, China.
  
  
  METHODS
  A prospective study was conducted for healthy pregnant women in first trimester (n = 334), second trimester (n = 272), third trimester (n = 271) and non-pregnant controls (n = 77) from December 2012 to June 2013 at our hospital. Free triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH), triiodothyronine (TT3) and thyroxine (T4) of four groups were measured and analyzed. And the reference intervals for different trimesters were established.
  
  
  RESULTS
  TSH declined in the first trimester and then rose in the second trimester. The reference ranges of TSH for early, middle and late pregnancy were 0.08-4.39, 0.41-4.16 and 0.30-5.46 mIU/L respectively. FT4 and healthy control groups showed no significant difference in the first trimester. But it declined in the second trimester. The reference ranges of FT4 for early, middle and late pregnancy were 7.74-14.58, 6.81-12.00 and 6.36-10.99 pmol/L respectively. FT3 rose slightly in the first trimester and then gradually decreased. The reference ranges of FT3 for early, middle and late pregnancy were 3.59-5.59, 3.34-4.91 and 3.09-4.58 pmol/L respectively.
  
  
  CONCLUSIONS
  As compared with healthy control women in Shenzhen, thyroid function indicators of pregnant women show statistically significant differences. And the establishment of indicators of women's thyroid function reference intervals for different trimesters has important clinical significance in Shenzhen.
authors.affiliation: Department of Laboratory Medicine, Shenzhen People's Hospital, Shenzhen 518020, China.
authors.forename: Lian
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Laboratory Medicine, Shenzhen People's Hospital, Shenzhen 518020, China.
authors.forename: Huakui
authors.initials: H
authors.lastname: Yue
authors.affiliation: Department of Laboratory Medicine, Shenzhen People's Hospital, Shenzhen 518020, China.
authors.forename: Haoyun
authors.initials: H
authors.lastname: Lin
authors.affiliation: Department of Laboratory Medicine, Shenzhen People's Hospital, Shenzhen 518020, China. Email: wuy_193@yahoo.com.
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Wu
mesh_terms: D002681:China; D005260:Female; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012016:Reference Values; D013960:Thyroid Function Tests; D013961:Thyroid Gland; D013972:Thyrotropin; D013974:Thyroxine; D014284:Triiodothyronine
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine