Here's How Well the Most Common Forms of Birth Control Actually Work

One of the most important things to know when choosing a method of birth control is how well it works. That’s especially important in a country where childbirth is expensive, maternal mortality is shockingly high, and our options for abortion are limited and shrinking.

No contraceptive method is perfect, of course. A birth control method’s effectiveness is measured in two ways. One is the “perfect use” rate, which reflects the chances of having a baby when you do everything right every single time: you never miss a pill or forget to use a condom, for example. Everything works as designed. These calculations often reflect very low failure rates.

But then there is the “typical use” statistic, which gives the failure rate that people actually experience in the real world when attempting to use that method. This includes all the variables that perfect use doesn’t capture. Maybe you forget to use it or don’t bother to use it consistently; or maybe there are factors outside your control, like a guy who slips the condom off without telling you, or you’re prescribed a medication that you didn’t realize can interfere with your birth control pills.

Abstinence advocates are fond of saying that it is the only birth control method with a 0% failure rate. That’s only the perfect-use rate, though. In reality, people don’t always stick to it all that well. (As far as I can tell, there is no agreed-upon typical use rate for abstinence, but abstinence-only education programs definitely do not result in zero pregnancies among their students.)

So, let’s take a look at some of the most common contraceptive methods, and the real-world failure rates of each. The failure rate is defined as how many people who use the method will become pregnant over the course of a year. So it’s not the failure rate per use or per sex act; it’s the chance of having a baby after a year of relying on this method.

The statistics here are from the CDC. We’ve ordered them from highest to lowest typical-use failure rates. Note that the “failure” rate of doing nothing at all is 85%. That means that if you can get pregnant, are sexually active, and use no birth control at all, you have an 85% chance of getting pregnant within a year.

That said, effectiveness is not the only consideration when you’re deciding what form of contraception to use. You may have medical or personal reasons to prefer one method over another. But it’s helpful to know what numbers you’re dealing with.