600907 Provided is a transdermal system for contraceptive treatment of females comprising a carrier formulation including an amount of a progestin comprising 16-methylene-17a-acetoxy-19- norpregn-4-ene-3,20-dione sufficient to provide absorption of a daily dose of at least about. 300 micrograms of said progestin to said female and to therefore provide mean plasma levels of at least about 500 pmol/L and estradiol sufficient to provide absorption of a daily dose of at least about 100micrograms of said estradiol to said female, whereby said transdermal system effectively blocks ovulation in the female and follicular development and rupture are prevented while irregular bleeding is minimized.
