Ovulation inhibition doses of progestins: a systematic review of the available literature and of marketed preparations worldwide

BackgroundThe objective of this analysis was to provide a comprehensive review of ovulation inhibition data of progestins currently available worldwide. This analysis may serve as a reference tool for research on new progestin molecules.Study DesignWe used literature search engines to detect data of progestin monotherapies on ovulation inhibition in humans. Only treatments with stable dosing during a cycle were accepted. In a second step, we tried to estimate the 99% ovulation inhibiting doses and their fiducial confidence limits using the probit dose–response model. Finally, we analyzed the progestin doses of combined oral contraceptives currently on the market.ResultsWe found original data on 29 marketed and nonmarketed progestins in a total of 60 publications, published between 1956 and May 2010. Details on methods used for determining ovulation, number of doses and daily dose of each tested progestin, number of subjects, cycles and ovulations are summarized in a table. We designed one example of a dose–response curve using the statistical model. For most progestins, literature data were insufficient for this purpose. A total of 13 progestins are components of oral contraceptives currently on the market worldwide, five of them in combination with 20 mcg ethinyl estradiol (EE).ConclusionThis review provides a comprehensive overview of all progestins ever tested for their ovulation inhibition potency and a summary of all preparations currently on the world market, including their regimens and their combinations with EE.