ObjectiveTo analyze the range of reference value of serum thyroid function in middle and late pregnancy.Methods500 cases of pregnant women who

receivedpregnancy check in our hospital from February 2016 to February 2017 were enrolled as the study group,among them,it included 300 cases of middle pregnancy women and 200 cases of late pregnancy women.Another 200 cases of healthy non－pregnant women of childbearing age were enrolled as the control group.The serum level of free thyroxine (FT4),thyroid stimulating hormone (TSH),thyrotropin receptor antibody (TRAb),anti－thyroglobulin antibody(TgAb)and anti－thyroid peroxidase antibody(TPOAb)of the subjects were detected by chemiluminescence immunoassay,the reference value of FT4and TSH in middle and late pregnancy were initially tested by methods which recommended by American Institute of Clinical Biochemistry(NACB).ResultsThe distribution situation of serum FT4was ranged from 9.79 to 17.29 pmol/L and 9.53 to 16.85 pmol/L in middle and late pregnancy respectively.The distribution situation of serum TSH was ranged from 0.64 to 5.33 mIU/L and 0.61 to 5.62 mIU/L in middle and late pregnancy respectively.The incidence rate of thyroid disease was 7.2%(36/500)when the above reference was used as the judgment criterion.ConclusionEstablishing the normal range of serum thyroid hormone level in different stages of pregnancy can provide a scientific basis for the diagnosis and treatment of thyroid disease during pregnancy.