A study on thyroid functions of pregnant women in urban areas of Hangzhou City

Objective To investigate thyroid function in pregnant women during different trimesters of pregnancy in Hangzhou City,and to provide evidence for the necessity and probability of screening for thyroid functions.Methods The urinary iodine levels and indexes of thyroid function of 160 pregnant women and 51 non-pregnant women were determined.The urinary iodine level was measured by spectrophotometer method.The levels of thyroid-stimulating hormone(TSH),free thyroxine(FT4),free triiodothyronine(FT3),total thyroxine(TT4),total triiodothyronine(TT3),thyroid peroxidase antibody(TPOAb)and thyroglobulin antibody(TGAb)were measured by a chemiluminescence assay.Results ① The median urinary iodine concentrations during the first,second and third trimesters of pregnancy were 157.30 μg/L,177.95 μg/L and 162.15 μg/L,respectively,and were all not significantly different from that of non-pregnant women,which was 170.50 μg/L(Z=-0.60,P=0.55;Z=-0.93,P=0.35;Z=-1.40,P=0.16).② The serum TSH level during the first trimester was obviously declined compared with that of the non-pregnant women.FT4 levels were gradually decreased with increasing gestational age.The TT4 level was markedly elevated and reached peak at the sencond trimester,approximately 1.41 times of that in non-pregnant women,and the TT3 levels reached peak at the third trimester,approximately 1.55 times of that in non-pregnant women.③ Compared with the normal values of TSH and FT4,the values of more than 90% of the pregnant women were in the normal range.④ Of the 21(10.3%)autoantibody-positive women,6 were non-pregnant and 15 were pregnant.Conclusion ① The nutritional status of iodine was optimized in pregnant women in Hangzhou City.② The thyroid hormone levels were completely different from that of the non-pregnancy and among gestation periods.③ The levels of TSH,FT4 in pregnant women of Hangzhou City were in normal status.