This is about the same efficacy asoral contraceptives.
Patches are usually self-adhesive andrelease hormones through your skinin a measured amount over a week.
A patch is not worn on the fourth week of your cycle so that you have a menstrual period.

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What Side Effects Does the Birth Control Patch Cause?
Side effects specific to birth control patches usually involve skin irritation or intolerance.
In this case, abstinence, barrier methods, or emergency birth control medications are recommended.
These are:
Whats a Period on Birth Control Patch Like?
There are also government and non-profit programs that can help supplement or offset your costs for birth control.
U.S. Food and Drug Administration.Ortho Evra (norelgestromin/ethinyl estradiol) information.
U.S. Food and Drug Administration.FDA-approved drugs.
Planned Parenthood.Birth control patch.
Centers for Disease Control and Prevention.Contraception and birth control methods.
National Library of Medicine - Daily Med.Twirla: Levonorgestrel/ethinyl estradiol patch.
National Library of Medicine - Daily Med.Xulane: Norelgestromin and ethinyl estradiol patch.
MedlinePlus.Estrogen and progestin (transdermal patch contraceptives).
Planned Parenthood.What do I do if I make a patch mistake?
U.S. Food and Drug Administration.FDA approves first nonprescriptive daily oral contraceptive.
Planned Parenthood.Where do I get the birth control patch?