• Contraceptive efficacy of the 2 treatments was estimated by determination of pregnancy rates, using the Pearl Index and life table analysis (cumulative probability of pregnancy). Safety was evaluated throughout the study.
  

• Cycle control and compliance were assessed with diary cards containing bleeding and dosing information.
  

This is an open-label, multicenter, worldwide study to evaluate the contraceptive efficacy, safety, cycle control, compliance, and subject satisfaction of the transdermal patch compared with Triphasil. Fourteen hundred healthy women will receive study medication for either 6 or 13 cycles. The first 33% of subjects (~265 transdermal patch subjects and 200 Triphasil subjects) will be expected to complete 13 cycles of medication. All subsequent subjects will be expected to complete 6 cycles. The ratio of subjects assigned to the transdermal patch arm of the study and to the Triphasil arm will be 4:3. At admission (Visit 1) study drug (plus 3 reserve patches), diary cards and subject instructions for Cycle 1 are dispensed. The first patch will be applied and Triphasil pill will be taken on the first day of menses. Study medication and diary cards will be issued on day 28 of Cycles 1 (Visit 2) and 3 (Visit 3), and those continuing for 13 cycles will receive study drug again (plus 3 reserve patches) on day 28 of Cycles 6 (Visit 4) and 9 (Visit 5). Diary cards and empty medication packages will be collected at every visit. Final visits are on day 28 of Cycles 6 and 9. Diary card information is used to record compliance and bleeding information (to assess cycle control). Contraceptive efficacy was assessed by means of the Pearl Index and life table analysis (gross cumulative probability of pregnancy). Safety evaluations were based on adverse events, which were collected throughout the study, and changes in physical examinations, gynecologic examinations, vital signs, and laboratory results from prestudy to final visit. A transdermal patch, containing 6 mg NGM and 0.75 mg EE, delivering 250 ug NGM and 25 ug EE over 24 hours for 7 days, is worn for 1 week and replaced for 3 consecutive weeks.The fourth week is patch-free. A Triphasil pill is taken for 28 consecutive days at the same time each day.