[Prevalence of thyroid function in pregnant and lactating women in areas with different iodine levels of Shanxi province].

Objective: To investigate the effects of high iodine intake on thyroid function in pregnant and lactating women. Methods: A cross sectional epidemiological study was conducted among 130 pregnant women and 220 lactating women aged 19-40 years in areas with high environment iodine level (>300 μg/L) or proper environment iodine level (50-100 μg/L) in Shanxi in 2014. The general information, urine samples and blood samples of the women surveyed and water samples were collected. The water and urine iodine levels were detected with arsenic and cerium catalysis spectrophotometric method, the blood TSH level was detected with electrochemiluminescence immunoassay, and thyroid stimulating hormone (FT(4)), antithyroid peroxidase autoantibody (TPOAb) and anti-thyroglobulin antibodies (TGAb) were detected with chemiluminescence immunoassay. Results: The median urine iodine levels of the four groups were 221.9, 282.5, 814.1 and 818.6 μg/L, respectively. The median serum FT(4) of lactating women in high iodine area and proper iodine area were 12.96 and 13.22 pmol/L, and the median serum TSH was 2.45 and 2.17 mIU/L, respectively. The median serum FT(4) of pregnant women in high iodine area and proper iodine area were 14.66 and 16.16 pmol/L, and the median serum TSH was 2.13 and 1.82 mIU/L, respectively. The serum FT(4) levels were lower and the abnormal rates of serum TSH were higher in lactating women than in pregnant women in both high iodine area and proper iodine area, the difference was statistically significant (FT(4): Z=-6.677, -4.041, P<0.01; TSH: Z=8.797, 8.910, P<0.01). In high iodine area, the abnormal rate of serum FT(4) in lactating women was higher than that in pregnant women, the difference was statistically significant (Z=7.338, P=0.007). The serum FT(4) level of lactating women in high iodine area was lower than that in proper iodine area, the difference was statistically significant (Z=-4.687, P=0.000). In high iodine area, the median serum FT(4) in early pregnancy, mid-pregnancy and late pregnancy was 16.26, 14.22 and 14.80 pmol/L, respectively, and the median serum TSH was 1.74, 1.91 and 2.38 mIU/L, respectively. In high iodine area, the serum FT(4) level in early pregnancy was higher than that in mid-pregnancy and late pregnancy, and the serum TSH level was lower than that in mid-pregnancy and late pregnancy, the difference was statistically significant (FT(4): Z=-2.174, -2.238, P<0.05; TSH: Z=-2.985, -1.978, P<0.05). There were no significant differences in the positive rates of serum thyroid autoantibodies among the four groups of women and women in different periods of pregnancy (P>0.05). The morbidity rates of subclinical hyperthyroidism in pregnant women and lactating women in high iodine area were obviously higher than those in proper iodine areas, the difference was statistically significant (χ(2)=5.363, 5.007, P<0.05). Conclusions: Excessive iodine intake might increase the risk of subclinical hypothyroidism in pregnant women and lactating women. It is suggested to strengthen the iodine nutrition and thyroid function monitoring in women, pregnant women and lactating women in areas with high environmental iodine.目的： 分析高碘摄入对孕妇及哺乳期妇女甲状腺功能的影响。 方法： 采用描述流行病学横断面对比研究方法，于2014年在山西省水碘含量>300及50~100 μg/L的地区选择调查点，抽取19~40岁孕妇130名、哺乳期妇女220名作为调查对象。记录一般资料，采集尿样、水样及血样，利用砷铈催化分光光度法检测水碘、尿碘含量，并通过电化学发光免疫分析法检测血清促甲状腺素（TSH）水平、化学发光免疫分析法检测血清游离甲状腺素（FT(4)）、抗甲状腺过氧化物酶自身抗体（TPOAb）、抗甲状腺球蛋白抗体（TGAb）水平。 结果： 适碘地区孕妇、哺乳期妇女、高碘地区孕妇、哺乳期妇女尿碘M分别为221.9、282.5、814.1、818.6 μg/L。高、适碘两地区内哺乳期妇女血FT(4) M分别为12.96、13.22 pmol/L，TSH M分别为2.45、2.17 mIU/L；孕妇血FT(4) M分别为14.66、16.16 pmol/L，TSH M分别为2.13、1.82 mIU/L。高、适碘两地区内哺乳期妇女血FT(4)水平低于孕妇、TSH异常值率高于孕妇，差异有统计学意义（FT(4)：Z=-6.677、-4.041，均P<0.01；TSH：Z=8.797、8.910，均P<0.01），高碘地区哺乳期妇女血FT(4)异常值率高于该地区孕妇，差异有统计学意义（Z=7.338，P=0.007），高碘地区哺乳期妇女血FT(4)水平低于适碘地区哺乳期妇女，差异有统计学意义（Z=-4.687，P=0.000）。高碘地区T1、T2、T3期孕妇血FT(4) M分别为16.26、14.22、14.80 pmol/L，TSH M分别为1.74、1.91、2.38 mIU/L，高碘地区内T1期孕妇血FT(4)高于T2、T3期孕妇、TSH水平低于T2、T3期孕妇，差异有统计学意义（FT(4)：Z=-2.174、-2.238，均P<0.05；TSH：Z=-2.985、-1.978，均P<0.05）。4组妇女间、不同孕期妇女血清中甲状腺自身抗体阳性率组内和组间比较差异均无统计学意义（均P>0.05）。高碘地区孕妇、哺乳期妇女亚临床甲状腺功能减退症（甲减）率均高于适碘地区，差异有统计学意义（χ(2)=5.363、5.007，均P<0.05）。 结论： 过量碘摄入可能增加孕妇和哺乳期妇女亚临床甲减发生的潜在风险，建议加强高碘地区孕妇和哺乳期妇女的碘营养及甲状腺功能监测。.