How effective is the patch at preventing pregnancy?

The patch can be very effective, but only when it’s changed on time. With perfect use, that means changing your patch every week and applying a new patch on time, the patch is more than 99% effective. Typical use, that means how real people use it in real life, is far more likely, and that makes the patch around 93% effective.

In other words:

For people who use the patch exactly as directed for a whole year, fewer than 1 in 100 will get pregnant when they don’t want to during the first year of using the patch.

For people who do not use the patch exactly as directed, about 9 in 100 will get pregnant when they don’t want to during the first year of using the patch.