The effectiveness of desogestrel for endometrial protection in women with abnormal uterine bleeding-ovulatory dysfunction: a non-inferiority randomized controlled trial

Women with chronic abnormal uterine bleeding-ovulatory dysfunction (AUB-O) are at increased risk of endometrial neoplasia. We conducted a non-inferiority randomized controlled trial to determine the effectiveness of two cyclic-progestin regimens orally administered 10 d/month for 6 months on endometrial protection and menstruation normalization in women with AUB-O. There were 104 premenopausal women with AUB-O randomized to desogestrel (DSG 150 µg/d, n = 50) or medroxyprogesterone acetate (MPA 10 mg/d, n = 54) group. Both groups were comparable in age (44.8 ± 5.7 vs. 42.5 ± 7.1 years), body mass index (24.8 ± 4.7 vs. 24.9 ± 4.7 kg/m(2)), and AUB characteristics (100% irregular periods). The primary outcome was endometrial response rate (the proportion of patients having complete pseudodecidualization in endometrial biopsies during treatment cycle-1). The secondary outcome was clinical response rate (the proportion of progestin withdrawal bleeding episodes with acceptable bleeding characteristics during treatment cycle-2 to cycle-6). DSG was not inferior to MPA regarding the endometrial protection (endometrial response rate of 78.0% vs. 70.4%, 95% CI of difference − 9.1–24.4%, non-inferiority limit of − 10%), but it was less effective regarding the menstruation normalization (acceptable bleeding rate of 90.0% vs 96.6%, P = 0.016). Clinical trial registration: ClinicalTrials.gov (NCT02103764, date of approval 18 Feb 2014).