Objective: To analyze the effects of progestin dose and time since the last spontaneous menstrual period (LMP) on bleeding profiles with two continuous, combined hormone replacement regimens in postmenopausal women.Methods: A randomized, double-blind, multicenter trial was conducted with 553 women recruited from 99 sites. Women received a continuous oral regimen of 0.625 mg/d conjugated equine estrogens combined with either 2.5 mg/d or 5.0 mg/d of medroxyprogesterone acetate (MPA) for 1 year (12 cycles).Results: After 1 year, more women in the 5.0-mg MPA group reported no bleeding (94%), compared with women in the 2.5-mg MPA group (90%; P <0.001). After three cycles for women 3 years or less from their LMP, 72.4% of women in the 5.0-mg MPA group did not experience bleeding, compared with 59.0% in the 2.5-mg MPA group (P <0.001). This trend was also noted after 6 months and 1 year; however, those differences were not statistically significant. For women more than 3 years since their LMP, 95% in the 5.0-mg MPA group and 91% in the 2.5-mg MPA group reported no bleeding after 1 year.Conclusions: The continuous combined regimen of conjugated equine estrogens plus 5.0 mg MPA may be more suitable for women closer to the onset of menopause, or for women initiating therapy who are more likely to discontinue due to irregular bleeding. Thus, the improved bleeding profile with this regimen may enhance HRT compliance, particularly in the early cycles of therapy.