Comparative study on the efficacy, acceptability, and side effects of a contraceptive pill administered by the oral and the vaginal route: an international multicenter clinical trial.

The objective of this multicenter randomized clinical trial was to compare the efficacy, acceptability, and occurrence of side effects associated with the oral versus vaginal route of administration of contraceptive pills. Eight hundred nineteen healthy, parous women of reproductive age were recruited at family planning clinics and research centers, members of the South to South Cooperation in Reproductive Health, in seven countries of the developing world. These women were randomly assigned to use either oral or vaginal administration of the same contraceptive pill, which contained 250 micrograms levonorgestrel and 50 micrograms ethinyl estradiol. No statistically significant differences were found in discontinuation rates between the two groups after 1 year. Involuntary pregnancy rates after 1 year were not statistically significantly different between the two groups. The vaginal route of administration appears to be as acceptable and efficacious as the oral route.