Evaluation of the exponential rise of serum estradiol concentrations in human menopausal gonadotropin-induced cycles.

To determine whether the rate of the exponential rise of estradiol (RER-E2) may be useful in monitoring gonadotropin-induced cycles and have prognostic value with respect to pregnancy, the RER-E2 was evaluated in 70 ovulatory cycles of 25 women. Semilogarithmic plots of E2 concentrations (picograms per milliliter) versus time (days) were linear, with slopes (RER-E2) ranging from 0.18 to 0.74. The mean RER-E2 in the 14 cycles of conception (0.49 +/- 0.03; +/- standard error) was not significantly different from the mean (0.47 +/- 0.02) in 56 cycles in which pregnancy did not occur. The mean of the RER-E2 of three twin pregnancies (P less than 0.02) and of three pregnancy losses (P less than 0.01) were significantly higher than the mean of nine singleton pregnancies. There was a lower pregnancy rate at the lower range of RER-E2 and a higher frequency of twin pregnancies and pregnancy losses at the upper range, but these trends were not statistically significant. By a graphic method, subsequent E2 values were predicted in 25 of 28 cycles within the 95% confidence limits and a clinically acceptable range of actual E2 values. The semilogarithmic plots appear to be useful adjuncts in the monitoring of gonadotropin-induced cycles. Although the data suggest that the RER-E2 may have prognostic value, further study is needed to confirm these observations.