Effectiveness shows the likelihood of getting pregnant while using a birth control method. Let’s use the Pill as an example. The Pill is 93% effective according to the CDC. That means that 93% of people won’t get pregnant in a year using that method. To put it another way, if 100 people use this method for a year, 93 of them won’t get pregnant.

The medical community talks about efficacy in two ways: perfect-use and typical-use.

Perfect-use effectiveness describes how likely you are to get pregnant if you use a method exactly according to the guidelines. Using the Pill perfectly would mean that you take it at the exact same time every day, never miss doses, or use a backup method while taking certain medications that could make it less effective.

Typical-use effectiveness describes how likely you are to get pregnant if you use a method “typically.” When researchers determine typical-use they study real people actually using the method in their everyday lives over the course of a year and see how many of those people get pregnant. With condoms for example, that group would include people who don’t always use condoms when they have sex or don’t put them on or take them off correctly.

It’s hard to be perfect. That’s why on our birth control materials we use typical-use efficacy whenever possible. If your preferred method has a lower typical-use efficacy rate than you are comfortable with, talk to your medical provider about ways to make it more effective. Your provider might suggest setting reminders on your phone, show you how to put condoms on and take them off correctly, or resources to use with Fertility Awareness Methods such as apps or charts.

When we say a method is hidden, we mean that people won’t be able to tell that you are on birth control. A method is considered hidden if it is placed inside your body (like IUDs) or otherwise not visible so that no one can see it or see you using it. Condoms, Fertility Awareness Methods, the Patch, the Pill, the Ring, and others are not hidden because people might see the method, the packaging it comes in, or you using it. For example, someone might find your birth control pills in the bathroom cabinet or see you chart your cycle using Fertility Awareness Methods on a calendar or app.

These methods are considered hidden: Breastfeeding as Birth Control, Hormonal IUDs, the Non-Hormonal IUD, the Implant, and the Shot. If you need a hidden method to protect your safety, talk to your provider. They can talk with you about hidden methods to consider, ways to make them more discreet (such as trimming the strings of your IUD), and resources/guidance on safety planning.

Resources: Talking to your healthcare provider about intimate partner violence

Some methods can affect your menstrual cycle/period—some methods (like Hormonal IUDs) typically make your periods lighter, while others might increase bleeding or menstrual cramps (like the Non-Hormonal IUD). These changes can be temporary, may continue the whole time you use the method, or for a period of time after you stop using it. Everyone is different. We describe on our materials the changes most people can expect to their bleeding patterns from a birth control method. However, it does not mean that this will be your experience!

Off-label means when you use a method in a way that has not been approved by the FDA. Using a birth control method off-label under the care of a provider does not mean that it is unsafe. For example, the Non-Hormonal IUD is FDA-approved as a form of ongoing birth control. It is not FDA-approved as Emergency Contraception. However, numerous studies have shown that using the Non-Hormonal IUD as Emergency Contraception is safe and effective. In fact, it is the most effective form of Emergency Contraception. The Non-Hormonal IUD and other methods can also be used off-label for longer than they are officially indicated for. Clinical studies have shown that the Hormonal IUD Mirena is safe and effective for up to 7-years, even though it is only currently FDA-approved for 6-years.

You don’t have to use a method off-label if you are not comfortable with it, even if your provider suggests it.

We use the term side effect to describe medical reactions or effects that you might have from using a birth control method. Many methods have side effects and it’s important to be aware of them so that you can make informed decisions that are right for you. We list the most common side effects in our materials, but there are others. A birth control method might have a side effect of headaches, but it does not mean that you will get them. Alternatively, a birth control method might not be associated with headaches, but you might get them after you start using the method. Everyone’s bodies are different. Talk to your provider about any side effects that you want to avoid or are concerned about in a method. They can help you find a method(s) that meets your needs.