Testosterone, Androstenedione and Dehydroepiandrosterone in Plasma During Pregnancy and at Delivery: Concentration and Protein Binding

Pregnancy produces a significant (p <0.01) increase in the concentration of testosterone (T) in plasma (nonpregnant females 49 ±13; pregnant females 114 ±38 mμg/100 ml), a nonsignificant increase in the androstenedione (A) concentration (nonpregnant 181 ±59; pregnant 249 ±82 mμg/100 ml) and a nonsignificant decrease in the dehydroepiandrosterone (D) concentration (nonpregnant 502 ±88; pregnant 363 ±233 mμg/100 ml). There was no correlation between fetal sex and maternal concentration of T and D. Mothers bearing a male fetus tended to have Δ values higher than those of mothers bearing a female fetus; the difference, however, was not significant. At delivery, the plasma concentrations of Δ and D were significantly higher than those during pregnancy, while the plasma concentration of T was similar. In every instance, the concentrations of T, Δ and D in the plasma of cord vein were lower than those of the corresponding maternal plasma. There was no correlation between the sex of the newborn and the concentrations of the 3 androgens in the plasma of cord vein. Pregnancy significantly increased the percentage of T-binding and D-binding, but it did not change that of Δ-binding, when using equilibrium dialysis at 37 C, with diluted plasma samples.