 Multiple pathologic predictors of complete response to progesterone therapy have been identified. In a recent study, Gunderson found that an interval decrease in glandular cellularity on endometrial biopsy after treatment with progesterone therapy was an independent predictor of future complete response. While both decreased mitotic index and decreased glandular cellularity were significant findings in this study, only decreased glandular cellularity was independently predictive of future complete response on multivariate analysis. 