When you use the patch correctly, it’s great at preventing pregnancy. But things like forgetting to change your patch or taking certain medicines can make it not work as well.
Birth control patch effectiveness
If you use it perfectly, the patch is 99% effective. But people aren’t perfect, and it can be easy to make a mistake — so in reality, the patch is about 91% effective. That means about 9 out of 100 patch users get pregnant each year.
The better you are about changing your patch on time, the better it will work. But there’s a very small chance that you could still get pregnant, even if you always use the patch correctly. In fact, your chances of getting pregnant on the patch depends on how well you follow the directions for using it. Make sure the patch sticks securely to your skin and don’t reapply a patch that is no longer sticky. Check your patch every day to make sure all the edges are sticking correctly.
If you often forget or misplace things, you may want to use another method that you don’t have to remember to change every week, like the IUD, implant, shot, or ring. They’re the best at preventing pregnancy and the easiest to use, since you don’t have to remember to do anything for it to work. But if you decide the patch is right for you, make sure you always put your new patch on on time so it works as well as possible.
What makes the patch less effective?
The main thing that makes the patch not work is not using it correctly. That means you’re more likely to get pregnant if you don’t put on a new patch every week, or if the patch falls off for more than 2 days.
Some medicines or supplements can also make the patch less effective:
• The antibiotics Rifampin, Rifampicin, and Rifamate (other antibiotics don’t make the patch less effective)
• The antifungal Griseofulvin (other antifungals don’t make the patch less effective)
• Certain HIV medicines
• Certain anti-seizure medicines (these are sometimes also used to treat psychiatric disorders like bipolar disorder)
• The herb St. John’s Wort
The patch may not work quite as well at preventing pregnancy if you’re overweight. Your nurse or doctor can help you decide if there’s any reason the patch won’t work well for you.