Lee Richard H, Spencer Carole A, Mestman Jorge H, Miller Erin A, Petrovic Ivana, Braverman Lewis E, Goodwin T Murphy
Department of Obstetrics and Gynecology, Women's and Children's Hospital, Los Angeles County-University of Southern California Medical Center, Los Angeles, CA, USA.
Am J Obstet Gynecol. 2009 Mar;200(3):260.e1-6. doi: 10.1016/j.ajog.2008.10.042. Epub 2008 Dec 27.
The purpose of this study was to evaluate the diagnostic accuracies of 2 free thyroxine immunoassays during pregnancy.
Serum was collected from healthy, thyroid peroxidase antibody-negative women during each trimester and nonpregnant controls. Thyrotropin, total T4 (TT4), free T4 index (FT4I), and 2 different FT4 immunoassays were studied.
As expected, TT4 was elevated in all 3 trimesters compared to controls (P < .001). FT4I was elevated in the 1st trimester as compared with controls (P < .05) and returned to the nonpregnant range in the 2nd and 3rd trimesters. In contrast, 1st trimester FT4 immunoassay values were either comparable or lower than controls and by the 2nd and 3rd trimesters had decreased to approximately 65% of controls.
Neither FT4 immunoassay accurately reflects established free T4 changes during pregnancy. TT4 and the FT4I retained an appropriate inverse relationship with TSH throughout pregnancy and appear to provide a more reliable free T4 estimate.
本研究旨在评估两种游离甲状腺素免疫测定法在孕期的诊断准确性。
收集健康、甲状腺过氧化物酶抗体阴性女性在孕期各阶段及非孕期对照的血清，对促甲状腺激素、总T4（TT4）、游离T4指数（FT4I）以及两种不同的游离T4免疫测定法进行研究。
正如预期，与对照组相比，TT4在孕期所有三个阶段均升高（P < 0.001）。与对照组相比，FT4I在孕早期升高（P < 0.05），并在孕中期和孕晚期恢复到非孕期范围。相比之下，孕早期游离T4免疫测定值与对照组相当或更低，到孕中期和孕晚期降至对照组的约65%。
两种游离T4免疫测定法均不能准确反映孕期游离T4的既定变化。TT4和FT4I在整个孕期与促甲状腺激素保持着适当的反向关系，似乎能提供更可靠的游离T4估计值。
