RESUMO
Objective To investigate and establish thyroid function reference range during 3 pregnant stages in Chaoshan area:thyrotropin (TSH),free thyroxin (FT4).Methods 863 healthy pregnant women visited antenatal clinic in the Second Affiliated Hospital were included in this study.By detecting serum levels of TSH,FT4,thyroglobulin antibody (TgAb),and thyroid peroxi-dase antibody (TPOAb)in these women,the euthyroid reference ranges of serum TSH and FT4 in different pregnant stages were established based on the standards of the United States National Institute of Clinical Biochemical (NACB)guidelines.Results The ranges of serum TSH in the first,second and third trimester of pregnancy were 0.13-3.93 mIU/L,0.14-4.55mlU/L,and 0.42-3.85 mIU/L,respectively.The ranges of serum FT4 levels in these 3 stages were 12.00-23.34 pmol/L,6.27-12.65pmol/ L, and 9.80-18.20 pmol/L,respectively.The range of serum TSH levels in our study were similar with the reference range recom-mended by the guidelines in China,but were different compared with the American Thyroid Association (ATA)guidelines.Conclu-sion TSH,FT4 levels show dynamic changes during different stages of pregnancy.The thyroid function ranges of healthy pregnant women in Chaoshan area are quite different compared with non-pregnant population and pregnant women in distinct area.Due to the differences of diet,iodine intake,economy and culture in Chaoshan area,regional thyroid function reference ranges specific for differ-ent stages of pregnant women should be established.