Contraceptive potential of a mifepristone-nomegestrol acetate sequential regimen in women

• Published in: Human reproduction (Oxford) 1998-12, Vol.13 (12), p.3297-3302
• Main Authors: Croxatto, H B, Salvatierra, A M, Fuentealba, B, Massai, R
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Birth control; Contraceptives, Oral, Combined - administration & dosage; Estradiol - blood; Female; Gynecology. Andrology. Obstetrics; Hormonal contraception; Humans; Luteinizing Hormone - urine; Medical sciences; Megestrol; Menstruation-Inducing Agents - administration & dosage; Mifepristone - administration & dosage; Norpregnadienes - administration & dosage; Ovulation - drug effects; Population; Progesterone - blood; Progesterone Congeners - administration & dosage; Sterilization, Reproductive
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/13.12.3297

The effectiveness of a sequential regimen consisting of mifepristone, 10 mg/day for 15 days, followed by nomegestrol acetate (NOMA), 5 mg/day for the next 13 days, for inhibiting ovulation and maintaining regular bleeding cycles was assessed in 10 surgically sterilized volunteers who were followed for one pretreatment and three treated cycles. Hormonal determinations in blood and urine, ovarian ultrasonography, bleeding records in all cycles and an endometrial biopsy taken on day 22-25 of the third treatment cycle were used to monitor the effects of treatment. During treatment, 24 monophasic (no sustained progesterone rise above 12 nmol/l) and six biphasic cycles were recorded. Nine follicular ruptures were detected echographically in these 30 treated cycles, five of which occurred in monophasic cycles. All follicular ruptures occurred on days 1-7 of NOMA treatment. Echographic and endocrine features of ovulatory cycles were both present in only four treated cycles (13.3%). Development of a secretory endometrium was achieved in all cases, but it was always irregular. Regular withdrawal bleeding occurred in all subjects and no adverse reactions were recorded. The ovarian and endometrial effects of this regimen justify testing its contraceptive effectiveness in phase 2 clinical trials.This study investigated the efficacy of mifepristone, 10 mg/day for 15 days, followed by nomegestrol acetate (NOMA), 5 mg/day for the next 13 days, for inhibiting ovulation and maintaining regular bleeding cycles in 10 surgically sterilized volunteers. To monitor the effects of treatment, hormonal determinations in blood and urine, ovarian ultrasonography, bleeding records in all cycles and endometrial biopsy were taken on day 22-25 of the third treatment cycle. About 24 monophasic and 6 biphasic cycles were recorded during treatment. About 9 follicular ruptures were echographically detected in these 30 cycles, 5 of which occurred in monophasic cycle. All follicular ruptures occurred in days 1-7 of NOMA treatment. Echographic and endocrine features of ovulatory cycles were both present in only four treated cycles (13.3%). Development of a secretory endometrium was achieved in all cases, but it was always irregular. Regular withdrawal bleeding occurred in all subjects and no adverse reactions were observed. The ovarian and endometrial effects of this regimen justify testing its contraceptive effectiveness in phase 2 clinical trials.