碘适量地区妊娠妇女妊娠全程甲状腺功能动态变化研究

Dynamic changes of thyrotropin and thyroid hormones during the pregnancy in iodine-adequate area

目的观察妊娠7周内甲状腺功能(甲功)正常妇女妊娠期间血清促甲状腺激素(TSH)和甲状腺激素的动态变化趋势及该组人群在妊娠过程中甲状腺功能减退(甲减)的发生情况。方法对2005年5月至2007年12月在沈阳地区10所医院妇产科门诊开展妊娠期甲状腺疾病的流行病学调查,239名妊娠7周(G7)内甲功正常的孕妇在G12至G36,每隔4周接受1次随访,应用固相化学发光酶免疫分析法检测血清TSH、总甲状腺素(TT4)、游离甲状腺素(FT4)、三碘甲状腺原氨酸(TT3)、游离三碘甲状腺原氨酸(FT3)、甲状腺过氧化物酶抗体(TPOAb)和甲状腺球蛋白抗体(TgAb)。按照妊娠期特异性TSH和甲状腺激素的参考范围计算甲减的发生率。结果血清TSH在G12降至最低点(与其他各时点比较,P均<0.01),之后逐渐回升。血清TT4在G12时升至高峰144.14nmol/L(G12对G6,P<0.01),之后维持在较高水平,均较基础水平明显升高(与G6比较,P均<0.01)。血清FT4自妊娠早期开始下降,至末期较平稳。血清TT3和FT3在G16前逐渐升高,之后稳定在高水平。6.7%基础甲功正常的孕妇在G12以后发生亚临床甲减,其基础TSH明显高于甲功持续正常的孕妇(P<0.01)。81.25%(13/16)的亚临床甲减发生在妊娠前半期。基础血清TSH>2.5mIU/L的孕妇在妊娠过程中发生亚临床甲减的比率为17.5%(14/80),明显高于基础血清TSH≤2.5mIU/L孕妇的发生率(P<0.01)。结论妊娠期间血清TSH和甲状腺激素随妊娠进展而变化;基础血清TSH>2.5mIU/L的孕妇在妊娠前半期更容易发生亚临床甲减。

Objective To explore the dynamic changes of serum TSH and thyroid hormones of the pregnant women with normal thyroid during the pregnancy and to observe the occurrence of subclinical hypothyroidism in these women during the pregnancy. Methods 239 pregnant women with normal thyroid were followed up regularly from G12 to G36 with the interval of 4 weeks. All the subjects underwent the planned thyroid tests regularly. Serum TSH, TT4, FT4, TT3, FT3 ,TPOAb and TgAb were measured. The incidence of subclinical hypothyroidism was obtained using trimester-specific reference intervals of TSH and thyroid hormones. Results Serum TSH decreased to nadir at G12 （ compared with other points, P 〈 0.01 ） and then increased gradually. Serum TT4 increased to the peak at G12 （ G12 vs. G6, P 〈 0. 01 ） and remained at the high level thereafter. Serum FT4 decreased gradually from the first trimester （G12 vs. G6, P = 0. 019） till the end of the pregnancy. Serum TT3 and FT3 increased gradually before G16, and stayed at the high level thereafter. 6. 7% of pregnant women with normal thyroid at G6 presented subclinical hypothyroidism during the pregnancy. The baseline TSH levels of the pregnant women who had subclincal hypothyroidism later were higher than those of others （ P 〈 0. 01 ）. The incidence of subclinical hypothyroidism in the pregnant women with baseline TSH 〉 2. 5 mIU/L was 17.5% （14/80） ,which was higher than that in the pregnant women with baseline TSH≤2. 5 mIU/L （P 〈 0. 01 ）. Conclusion The levels of serum TSH and thyroid hormones fluctuate at the different phases of pregnancy. The pregnant women with baseline TSH 〉 2. 5 mIU/L are susceptible to subclinical hypothyroidism.