Thyroxine-Binding Globulin Values as a Measure of Placental Adequacy

摘要

A new resin-sponge uptake method has been devised for the measurement of the serum thyroxine-binding globulin values. Since thyroxine-binding globulin levels reflect serum estradiol concentrations, this method serves as a useful index of fetal-placental viability in patients with threatened abortion. In contrast, it does not appear that thyroxine-binding globulin measurement is useful to determine the viability of the conceptus at term in spite of demonstrated lowered estrogen excretion levels. The latter is probably because the dose response of thyroxine-binding globulin to estrogen administration is not linear and is insensitive to variations in estrogen levels at higher concentrations than are found in term pregnancies. Additionally, this simplified technic for determining thyroxine-binding globulin values may be of use in the clinical evaluation of altered serum thyroxine levels secondary to androgen, estrogen, or anabolic steroid therapy.