To establish the reference value of thyroid function for pregnant women in Shantou area and screen the occurrence rate of thyroid function disorder for pregnant women in this area.

This study enrolled 837 pregnant women, who were conducted antenatal care in the Second Affiliated Hospital of Shantou University Medical College from January 2013 to December 2015. The serum of the patients was collected to detect thyroid hormones and thyroid autoantibodies. The values of serum thyroid stimulating hormone (TSH) and free thyroxine (FT₄) for 367 pregnant women during January 2013 to June 2014 were established reference standard. Four hundred and severty pregnant women, who were conducted antenatal care in our hospital from July 2014 to December 2015, were assessed thyroid function by using this reference standard.

(1) The reference value of serum TSH in first, second and third trimester of pregnancy were 0.07-5.34 mIU/L, 0.09-4.96 mIU/L and 0.05-6.59 mIU/L, respectively; And the reference value of serum FT₄ in the three different trimesters were 8.71-15.53 pmol/L, 5.58-11.84 pmol/L and 5.57-21.91 pmol/L, respectively. (2) The incidence rates of clinical hyperthyroidism, subclinical hyperthyroidism and subclinical hypothyroidism were 1.91% (9/470), 0.64% (3/470) and 1.06% (5/470). There were no one had clinical hypothyroidism.

Establish reference value of thyroid function for pregnancy in Shantou area is conducive to early diagnosis and treatment, which can reduce the damage to the mothers and fetuses.