正常孕妇垂体-甲状腺轴功能变化的研究

目的了解正常孕妇妊娠各期及产后垂体-甲状腺轴功能的变化;探讨妊娠期人绒毛膜促性腺激素(hCG)对垂体-甲状腺轴的调节作用.方法采用放射免疫法,测定正常孕妇妊娠早、中、晚期及产后甲状腺功能参数血清总三碘甲状腺原氨酸(TT3)、总甲状腺素(TT4)、血清游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺素(TSH)]、hCG及甲状腺结合球蛋白(TBG)的水平.结果(1)血清TT3、TT4水平在妊娠各期均较产后显著升高,其中TT4在妊娠早期最高为(170.00±40.28)nmol/L,TT3在妊娠中期最高为(2.64±0.53)mmol/L.(2)血清FT3水平在妊娠早期(4.37±0.78)pmol/L]和中期(4.75±0.90)pmol/L]显著升高,晚期(3.94±0.75)pmol/L]下降,产后最低(2.96±0.84)pmol/L];血清FT4妊娠早期最高(14.07±1.44)pmol/L],中期(12.86±0.84)pmol/L]和晚期(11.29±1.00)pmol/L]逐渐下降,产后(10.45±1.45)pmol/L]最低.(3)血清TSH水平在妊娠早期最低为(0.88±0.83)mU/L,妊娠中期(1.86±1.04)mU/L]和晚期(1.48±0.90)mU/L]上升,产后(2.82±1.42)mU/L]达最高峰.(4)血清hCG水平在妊娠早期最高为(309.05±320.02)μg/L,中期(69.11±19.18)μg/L]和晚期(86.25±44.60)μg/L]下降,产后(29.95±20.91)μg/L]最低.(5)hCG与TSH呈负相关,而与FT4、TT4呈正相关.结论(1)hCG可能在整个妊娠期及产后一定时间内,对垂体-甲状腺轴功能有一定的调节作用.(2)产后部分孕妇处于一过性甲状腺功能低减状态.

Longitudinal study about the function of pituitary-thyroid axis in pregnancy

OBJECTIVE: To evaluate the change about the function of pituitary-thyroid axis and the role of human chorionic gonadotropin (hCG) on regulation of pituitary-thyroid axis in pregnancy. METHODS: The study was designed to provide longitudinal information of parameters of thyroid function and hCG in 74 healthy women during pregnancy and after delivery. Serum free triiodothyronine (FT3), free thyroxin (FT4), TT3, TT4, hCG and thyroid hormone binding globulin (TBG) concentrations were measured with radioimmunoassary and serum TSH concentration with immunoradiometric assay. RESULTS: (1) The FT3 and FT4 values below the reference range were 5.88% and 9.80%, respectively, in third trimester and after delivery, both were 38.10%. The serum TSH level below the reference range was 31.25% in first trimester and supranormal were 11.90% after delivery. The serum hCG level at all stages of pregnancy was higher than postpartum. (2) The serum FT3 level was significantly higher in first (4.37 +/- 0.78) pmol/L and second (4.75 +/- 0.90) pmol/L trimesters than postpartum (2.96 +/- 0.84) pmol/L, decreased in third trimester (3.94 +/- 0.75) pmol/L and the lowest level after delivery. The serum FT4 level was significantly higher in first (14.07 +/- 1.44) poml/L and second (12.86 +/- 0.84) pmol/L trimesters than postpartum (10.45 +/- 1.45) poml/L, decreased in third trimester (11.29 +/- 1.00) pmol/L and the lowest level after delivery. (3) The serum TSH level was the lowest values in early pregnancy (0.88 +/- 0.83) mU/L, showed significant increase in second (1.86 +/- 1.04) mU/L and third (1.48 +/- 0.90) mU/L trimesters and reached maximal level after delivery (2.82 +/- 1.42) mU/L. (4) The serum hCG level was the highest in early pregnancy (309.05 +/- 320.02) micrograms/L, then significant decreased in second (69.11 +/- 19.18) micrograms/L and third (86.25 +/- 44.60) micrograms/L trimesters and was the lowest levels after delivery (29.92 +/- 20.91) micrograms/L. (5) A significant negative correlation between TSH and hCG levels and a significant positive correlation between hCG and FT4 and TT4/TBG were demonstrated. CONCLUSIONS: (1) hCG may be as role on regulation of pituitary-thyroid axis during pregnancy and during certain time of postpartum. (2) After delivery, part of women were transient hypothyroxinemia.