Bleeding profile and endometrial safety of continuous combined regimens 1 mg 17[beta]-estradiol/trimegestone versus 1 or 2 mg 17[beta]-estradiol/norethisterone acetate in postmenopausal women

OBJECTIVE: To compare the bleeding profile and endometrial safety of continuous combined 1 mg 17beta-estradiol (17beta-E2) and 0.125 mg trimegestone (TMG) with those of two continuous combined 17beta-E2 and norethisterone acetate (NETA) regimens. STUDY DESIGN: This was a double-blind, randomized, multicenter study conducted in 12 European countries and Israel over a 2-year period. Healthy postmenopausal women with an intact uterus were given either 1 mg 17beta-E2/0.125 mg TMG, 2 mg 17beta-E2/1 mg NETA or 1 mg 17beta-E2/0.5 mg NETA for up to 26 cycles, each of 28 days. RESULTS: The percentage of amenorrheic women was greater in most cycles up to cycle 13 in the 1 mg 17beta-E2/0.125 mg TMG group than in the comparator groups. The mean number of bleeding days was similar in the 1 mg 17beta-E2/0.125 mg TMG and the 1 mg 17beta-E2/0.5 mg NETA groups, but greater in the 2 mg 17beta-E2/1 mg NETA group. No endometrial hyperplasia was observed for any group. CONCLUSION: Continuous combined 1 mg 17beta-E2/0.125 mg TMG exhibits a more favorable bleeding profile than 1 mg 17beta-E2/0.5 mg NETA up to 1 year, while providing an adequate protective effect on the endometrium.