Editing Contraceptive patch (section)

== Mechanism of action ==
[[File:Blausen 0080 BirthControlPatch.png|thumb|Illustration depicting transdermal contraceptive patch]]

Like all combined hormonal contraceptives, Ortho Evra / Evra works primarily by preventing ovulation. A secondary mechanism of action is inhibition of sperm penetration by changes in the cervical mucus. Hormonal contraceptives also have effects on the endometrium that theoretically could affect implantation; however, no scientific evidence indicates that prevention of implantation actually results from their use.<ref>{{cite journal | vauthors = Rivera R, Yacobson I, Grimes D | title = The mechanism of action of hormonal contraceptives and intrauterine contraceptive devices | journal = American Journal of Obstetrics and Gynecology | volume = 181 | issue = 5 Pt 1 | pages = 1263–1269 | date = November 1999 | pmid = 10561657 | doi = 10.1016/S0002-9378(99)70120-1 }}</ref>

The 20&nbsp;cm<sup>2</sup> Ortho Evra contraceptive patch contains 750&nbsp;μg [[ethinylestradiol]] (an estrogen) and 6000&nbsp;μg [[norelgestromin]] (a progestin).<ref name="Xulane label" /> The 20&nbsp;cm<sup>2</sup> Evra contraceptive patch contains 600&nbsp;μg ethinylestradiol and 6000&nbsp;μg norelgestromin.<ref name="Evra SmPC" /> The Ortho Evra contraceptive patch and the Evra contraceptive patch are both intended to gradually release into the systemic circulation approximately 20&nbsp;μg/day of ethinylestradiol and 150&nbsp;μg/day of norelgestromin.<ref name="Xulane label"/><ref name="Evra SmPC"/>