A comparative analysis of three different dose combinations of oral contraceptives

Three different low-dose formulations of oral contraceptives were compared to determine the most suitable preparation for Filipino women as reflected in the first year continuation rates, incidence of side effects and failure rates. A total of 1,800 subjects were enrolled in the study from 18 health centers in six provinces in two regions of the Philippines, covering a total of 18,282 women-months of use. Sociodemographic characteristics were comparable. The monophasic levonorgestrel group showed the best performance followed by the triphasic preparation. The norethindrone group consistently showed higher drop-out rates, which may be due to the relatively higher incidence of side effects. For all three preparations, bleeding irregularities were low. There were no major side effects and no pregnancy was reported in one year of use. Noted was a distinct regional and provincial difference in recruitment and follow-up performance, possibly due to clinic, client or program factors.