Changes of thyroid function during pregnancy in the second and third trimester and in relation to iodine intake / 中华内分泌代谢杂志

ABSTRACT

Objective To evaluate the changes of thyroid function during pregnancy in the second and third trimester in the regions with or without iodine deficiency. Methods The serum TSH, FT 3, FT 4 and TT 4 levels of 90 pregnant women (30 from iodine deficient area as study group, 60 from iodine sufficient area as control group) and 30 non pregnant women were assayed by high sensitive immunoradiometric assay (IRMA) or radioimmunoassay (RIA), and urine iodine level of pregnant women before delivery was also examined. Results (1) The serum TSH level in pregnant women in the second and third trimester was significantly higher than that of non pregnant women. The serum free thyroid hormone levels of pregnant women were significantly lower than that of non pregnant women, especially in the third trimester. (2) The serum TSH level of pregnant women from iodine deficient area in the second trimester and before delivery was significantly higher than that of pregnant women from iodine sufficient area (P