Review of ovulation return upon discontinuation of once-a-month injectable contraceptives.

ABSTRACT

Once-a-month combined injectable preparations draw their contraceptive efficacy from continuous ovulation suppression. When their use is discontinued, ovulation resumes within a few weeks or a few months, depending on the formulation. After use of the dihydroxyprogesterone acetophenide 150 mg/estradiol enanthate 5 mg combination for one to two years, ovulation returns in most subjects 3-4 months after discontinuation of treatment. Similarly, recent data show that after 2-year use of the depot-medroxyprogesterone acetate 25 mg/estradiol cypionate 5 mg or the norethisterone enanthate 50 mg/estradiol valerate 5 mg combination, approximately 70% women have resumed ovulation by the third month post-treatment. This is shorter than the time for return of ovulation experienced by ex-users of progestogen-only injectable contraceptives.

ABSTRACT

PIP This paper reviews the progress made in the determination of ovulation and specifically addresses the effects of returning ovulation after discontinuance of once-a-month injectable contraceptive preparations. Correlation between ovulation and the hormones estrogen, progesterone, and luteinizing hormone (LH) is well documented. It has served as the basis for many studies on determining ovulation mid-point and in evaluating the efficacy, safety, and time of returned ovulation when using various contraceptive methods and preparations. Current monthly injectable contraceptive formulations are discussed and used as comparison for the new generation injectables. New generation contraceptives in this study are preparations (combinations) of several compounds. The depot microcrystalline form of medroxyprogesterone acetate (DMPA) in combination with estradiol cypionate (E2-Cy) was studied. The authors conclude that these initial studies on the new generation combination monthly injectables indicate that these new contraceptives are highly effective in inhibiting ovulation, as well as allowing for predictable return of ovulation.