EFFECTS OF A SINGLE CONTRACEPTIVE SILASTIC IMPLANT CONTAINING NOMEGESTROL ACETATE ON OVARIAN-FUNCTION AND CERVICAL-MUCUS PRODUCTION DURING 2 YEARS

Objective: To study the mechanism of action of Uniplant (South to Sout h Corporation in Reproductive Health, Salvador, Brazil), a single Sila stic capsule containing nomegestrol acetate (Lutenyl, Theramex, France ) in women during 2 years. Design: Comparison between the hormonal lev els, follicular development, cervical mucus (CM) production, and endom etrial thickness in the menstrual cycle before implant insertion and a t 1, 6, 12, 18, and 24 months after implant insertion. Participants: A total of 15 women of reproductive age were enrolled for the Ist year of use. Twelve of these women continued for a 2nd year of Uniplant use .Main Outcome Measures: Hormonal plasma levels were measured in contro l cycles and at 1, 6, 12, 18, and 24 months of Uniplant use. Cervical mucus, follicular development, and endometrial thickness also were eva luated. Results: In this study, Uniplant blocks ovulation in 86% of cy cles studied. Disturbances in follicular growth were observed also. Ce rvical mucus was scanty and viscous in all women during this study. En dometrial thickness was <8 mm in all cycles studied. Conclusion: This study shows that Uniplant is a long-acting contraceptive that probably acts at the hypothalamic-pituitary levels, on the ovary, on CM produc tion, and on the endometrium. These properties suggest the use of Unip lant as a contraceptive agent, especially if one considers the lack of androgenic and metabolic effects and the maintenance of periodic blee ding similar to menstruation.