Analysis of surveillance results of iodine-nutritional status and thyroid function of pregnant women at different stages of pregnancy in Taizhou City of Jiangsu Province

Objective To investigate iodine nutritional status of pregnant women of Taizhou City, in order to provide a basis for assessment whether normal consumption of iodized salt is needed, to take complement iodine measure and to carry out monitoring of urinary iodine and thyroid function in pregnant women. Methods Early pregnancy (gestation < 4 months), medium (4 to 7 months gestation) and late (pregnancy≥8 months) of each of more than 300 pregnant women were chosen from maternal and child health (hospital) and part of the township hospitals of Taizhou City (district) from September 2012 to December 2013. Based on the principle of informed consent, disposable urine and blood samples were collected, urine iodine and thyroid hormone [serum thyroid stimulating hormone (TSH), three free triiodothyronine (FT3) and free thyroid hormone (FT4)] were measured. Urinary iodine was measured using a urinary iodine rapid quantitative detection kit, thyroid function was measured by an electrochemical method. Use 95% of the reference value range of thyroid function in pregnant women as the basis for evaluation of thyroid function in pregnant women. Results A total of 997 pregnant women were investigated, early stage, mediumterm and late pregnancy women were 302, 357 and 338, respectively. The median urinary iodine was 124, 129, 119 μg/L, pregnant women in late pregnancy had the lowest iodine urine. The median TSH of early stage, medium-term and late pregnancy women were 2.03, 2.18, 2.22 mU/L; the mean FT3 and FT4 of the three groups were (4.39±0.66), (4.06±0.61), (3.92 ± 0.61)pmol/L and (14.56±2.56), (13.08 ± 2.03), (12.70 ± 2.38)pmol/L, respectively. The rate of abnormal thyroid function was 4.91% (49/977), mainly in subhypothyroidism [48.98% (24/49)]. Conclusions Poor iodine-nutritional status exists in some pregnant women in Taizhou City. It is necessary to strengthen the propaganda and education of pregnant women on iodine supplement knowledge in the future, and carry out routine monitoring of urinary iodine and thyroid function in early pregnancy. Key words: Pregnant woman; Iodine-nutrition status; Thyroid function