Prior to enrollment, participants underwent a physical examination including gynecologic examination. Women on hormonal contraceptives at recruitment were given barrier contraceptives for two months prior to starting the study. Participants were assigned a random identification number which indicated the sequence in which transdermal or oral contraceptives would be given. The daily oral contraceptive or weekly transdermal contraceptive was given with the typical dosing of three weeks active treatment followed by one week without hormone use. Following the first two months of hormonal contraceptive, each participated returned to barrier contraceptive for a two month washout period, then received two months of the alternative hormonal contraceptive. The investigators were blind to the order of contraceptive assigned for each participant.