胎儿及新生儿甲状腺激素水平的变化及意义

Thyroid functional changes of normal human fetus and newborns

目的 探讨不同胎龄的正常胎儿及新生儿甲状腺激素水平变化及意义。方法 对可疑有遗传、内分泌、感染、代谢性疾病的孕 16～ 3 6周胎儿 71例 (观察组 ) ,在B超引导下 ,行脐静脉穿刺 ,孕妇甲状腺功能均正常。选择同期孕足月自然分娩的 14 0例新生儿脐带血为对照组。测定两组甲状腺激素水平及甲状腺功能。并对孕 2 8周前后的胎儿甲状腺功能、胎儿与新生儿甲状腺激素水平进行比较。结果 自孕 16周起 ,胎儿甲状腺激素均可检测到 ,并随孕周增加而增加 ;游离甲状腺素 (FT4)在孕 16周时为 ( 5 8± 2 6)pmol L ,接近正常成人甲状腺素水平 ,以后持续上升 ;胎儿甲状腺素 (T4)、三碘甲状腺原氨酸 (T3)、FT4在 2 8孕周后较 2 8周前显著升高 ,即分别由 ( 2 8± 1 8)nmol L、( 3 7 2± 2 7 2 )nmol L、( 10 6± 3 1)pmol L增至 ( 5 8± 2 6)nmol L、( 55 9± 3 3 3 )nmol L( 13 0± 4 5)pmol L。孕 2 0周时 ,胎儿促甲状腺激素 (TSH)水平达到正常成人上限 ,为 ( 4 6± 1 4)mU L ,以后持续上升 ,分娩期达高峰 ,为 ( 9 2± 6 7)mU L。而T3 及游离三碘甲状腺原氨酸 (FT3)在整个孕期始终处于较低水平。结论 胎儿甲状腺激素水平随孕周增长而升高。孕中期以后 ,胎儿T4 、FT4 及TSH ,可作为判断胎儿甲状腺功能的主?

Objective To study the changes of the thyroid hormones leval of human fetus and newborans Methods More than 71 cases of medically indicated cordocentesis have been done in 16 36 gestational weeks in our hospital during last three years. Among them, 71 fetus who were free of diseases and their maternal thyroid function were normal were included into the study group. The blood samples were sent to analysis of thyroxine (T 4), triiodothyroxine (T 3), free thyroxine (FT 4), free triiodothyroxine (FT 3) and thyrotropin (TSH). 140 umbilical cord blood samples taken at the time of term delivery were sent to analysis of FT 4,FT 3 and TSH as a control. Normal range of different gestational weeks was calculated. Statistical analysis was done for the changes of all these thyroid hormones before 28 weeks and after Results All the thyroid hormones can be detected in 16 weeks of pregnancy,FT 4 already reaches the top level of adults (5.8±2.6) pmol/L and will continually increase with the increase of gestational age. There was a parallel increment of all the fetal thyroid hormone concentrations with the gestational age. The concentrations of T 4,T 3 and FT 4 have a rapidly increase after 28 weeks and have a statistically significant difference from (2.8 ±1.8) nmol/L, (37.2±27.2) nmol/L and (10.6±3.1) pmol/L,respectively to (5.8±2.6) nmol/L, (55.9±33.3) nmol/L,( 13.0±4.5) pmol/L, respectively. TSH level of fetus was increased gradually along the gestation, reaching the up level of the adults at the 20 weeks and peaking at the birth time. While the T 3 and FT 3 keep in a lower level in gestation Conclusions Fetal thyroid hormones increase with the gestational age.The diagnosis of congenital fetal thyroid hormone malfunction in the second half of the pregnancy should be monitored mainly by the T 4, FT 4 and TSH levels in different gestational age. For this consideration, to set up a reliable data for normal human fetus thyroid hormone concentrations is a very important and essential step to provide a practical guide for doctors to do intra uterine diagnosis and treatment of associated high risk groups. The peaking level of TSH at the birth time will surely company the changing of other thyroid hormones, so it might not be the best time to screening the congenital thyroid malfunction at the 72 hours after birth.