孕妇甲状腺功能变化及尿碘正常值范围的探讨

Investigation of thyroid function change and urinary iodine standard of pregnant women

目的 了解不同尿碘水平、不同孕期孕妇甲状腺功能变化.以孕妇正常甲状腺功能为金标准,探讨孕妇尿碘的正常值范围.方法 在甘肃和吉林省,选择缺碘农村地区孕早、孕中、孕晚期孕妇,每个省每个孕期最少70例.要求孕妇体格健康,并排除直系血源亲属中有甲状腺疾病史者.测定孕妇尿碘、甲状腺功能5项：游离三碘甲腺原氨酸（FT3）、游离甲状腺素（FT4）、促甲状腺素（TSH）、甲状腺过氧化物酶抗体（TPOAb）和甲状腺球蛋白抗体（TgAb）及家中盐碘.尿碘测定采用尿中碘的砷铈催化分光光度法（WS/T 107-2006）,甲状腺功能5项测定采用化学发光法,盐碘测定采用直接滴定法（GB/T 13025.7-1999）.结果 439名孕妇尿碘中位数为178.6 μg/L,其中甘肃省215名,尿碘中位数为156.4 μg/L;吉林省224名,尿碘中位数为206.4 μg/L.随着尿碘水平的升高,甘肃省孕妇FT3由5.77 pmol/L下降至5.34 pmol/L,TSH由最低时的2.63 mU/L升高至3.75mU/L;吉林省孕妇的FT3由4.41 pmol/L升高至4.45 pmol/L,TSH由最低时的0.92 mU/L升高至1.50 mU/L.3个不同孕期中,＞97％的孕妇甲状腺功能5项指标均在正常值范围,最稳定的指标为FT3.其中甘肃省孕妇3个孕期FT3分别为6.27、5.76、5.28 pmol/L,吉林省孕妇3个孕期FT3分别为4.50、4.42、4.32 pmoL/L.两省中甲状腺功能正常的孕妇,第5％分位数时尿碘为55.24 μg/L;第95％分位数时尿碘为581.27 μg/L.结论 不同尿碘水平、不同孕期的孕妇甲状腺功能相对稳定,TSH随尿碘的增加呈现升高趋势.随孕期的发展,虽然尿碘在不同孕期间有差别,但甲状腺功能变化不明显,甲状腺功能正常的孕妇尿碘范围在50 ～ 600 μg/L.

Objectives To study the changes of thyroid function under different urinary iodine levels and pregnant trimesters,and to investigate the urinary iodine standard of pregnant women,taken thyroid function as a golden standard.Methods Early,mid and late trimester pregnant women in the iodine deficient rural areas of Gansu and Jilin Provinces were selected,at least 70 cases were included for each trimester in each province.Pregnant women included were physically healthy;cases should be excluded if their immediate relatives had a thyroid disease history.Urinary iodine,free triiodothyronine （FT3）,free thyroxine （FT4）,thyroid stimulating hormone （TSH）,thyroid peroxidase antibody （TPOAb）,thyroglobulin antibody （TgAb）,and edible salt iodine from pregnant women＆#39;s home were tested.The urinary iodine was measured with the method for determination of iodine in urine by As3＋-Ce4＋ catalytic spectrophotometry （WS/T 107-2006）.Thyroid function was tested by chemiluminescence method,salt iodine was determined by direct titration method （GB/T 13025.7-1999）.Results Totally 439 pregnant women were investigated in the two provinces.Median of urine iodine was 178.6 μg/L;for the 215 women in Gansu,the value was 156.4 μg/L;for the 224 women in Jilin,the value was 206.4 μg/L.Along with the increase of urinary iodine,the FT3 of Gansu decreased from 5.77 pmol/L to 5.34 pmol/L,TSH increased from the lowest 2.63 mU/L to 3.75 mU/L;the FT3 of Jilin increased from 4.41 pmol/L to 4.45 pmol/L,TSH increased from the lowest 0.92 mU/L to 1.50 mU/L.Five indicators of thyroid function of more than 97% pregnant women were in normal range and FT3 was the most stable in the three trimesters.FT3 of the three triimesters in Gansu was 6.27,5.76,5.28 pmol/L,respectively,and that in Jilin was 4.50,4.42,4.32 pmol/L,respectively.The 5% and 95% quantile were 55.24,581.27 μg/L of urinary iodine,of pregnant women with normal thyroid function.Conclusions Under different urinary iodine levels,pregnant women＆#39;s thyroid function is relatively stable.TSH has showed an increasing trend with increasing iodine level.Along with the progress of pregnancy,the urinary iodine is different among the three pregnancy periods,but the thyroid function is stable.The pregnant women with normal thyroid function have a urinary iodine level between 50-600 μg/L.