When you use the patch correctly, it’s great at preventing pregnancy. But things like forgetting to change your patch or taking certain medication can make it less effective.
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Birth control patch effectiveness
If you use it perfectly, the patch is 99% effective. But people aren’t perfect, so in reality, the patch is about 91% effective. So 9 out of 100 patch users get pregnant each year.
You might forget to change your patch on time, or it might fall off. 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, or shot.
The better you are about changing your patch on time, the better it will work. But there’s a very small chance you’ll get pregnant, even if you use the patch perfectly.
What makes the patch less effective?
The main thing that makes the patch less effective is not using it correctly. That means you’re more likely to get pregnant if you don’t put on a new patch at the right time every week.
Rarely, a patch can fall off, and then you won’t get enough hormones to prevent pregnancy. The patch may be a little less effective for people who are very overweight.
Some medicines or supplements can also make the patch less effective:
• The antibiotics Rifampin, Rifampicin, and Rifamate (other antibiotics aren’t a problem)
• The antifungal Griseofulvin (other antifungals aren’t a problem)
• 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
If you’re taking any of these, use condoms as well as the patch for as long as you take them. Switch to a different type of birth control if you’ll be on them for a long time.
Your nurse or doctor can help you decide if there’s any reason the patch won’t work well for you.