This study was a randomized investigator-blind, cross-over clinical trial. The daily oral contraceptive contained 35 micrograms ethinyl estradiol and 250 micrograms norgestimate (Ortho Cylen®). The weekly transdermal hormonal contraceptive contained 0.75 milligrams ethinyl estradiol and 6.0 milligrams norelgestromin (Ortho Evra®). Norelgestromin is the active progestin metabolite of orally administered norgestimate. For the oral form the average steady state plasma concentration (Css) of ethinyl estradiol was 49.3 picograms/milliliter and of norelgestromin 0.73 nanograms/milliliter and for the transdermal form these concentrations were 80.0 picograms/milliliter and 0.888 nanograms/milliliter, respectively at the end of the second month of use.17 The average weekly exposure, calculated as area under the curve (AUC0-168pg.h/mL) for ethinyl estradiol was 55% higher with transdermal than with the oral contraceptive. The maximum ethinyl estradiol and norelgestromin levels (Cmax) were 133 pg/ml and 2.16 ng/ml for the oral form and 97.4 pg/ml and 1.12 ng/ml for the transdermal form.17 The application location of the patch does not alter the Css or Cmax.18 Medications were supplied to the patients by a research nurse and the completed packets were returned to document compliance. The contraceptives and the funding for the study were supplied by research grants from the University of Vermont Department of Obstetrics and Gynecology.