Sex education varies from one school to another. Maybe you learned everything you wanted to know. Or you might have been left with some pressing questions.

Here are 6 facts about birth control that you might not have learned in school.

Abstinence isn’t the only option

Avoiding sexual intercourse is the most effective way to avoid pregnancy, but it’s far from the only option.

Condoms and birth control pills are popular methods of contraception that many people know about. But a growing number of people are also discovering the potential benefits of long-acting reversible contraceptives (LARCs), such as the:

  • copper IUD
  • hormonal IUD
  • birth control implant

Each of these devices is more than 99 percent effective at preventing pregnancy, according to Planned Parenthood. A copper IUD can provide continuous protection against pregnancy for up to 12 years. A hormonal IUD can last for up to 3 years or more. An implant can last for up to 5 years.

Your medical history affects your choices

If you have a history of certain medical conditions or risk factors, some methods of birth control may be safer than others.

For example, some types of birth control contain estrogen. These types of birth control can raise your risk of blood clots and stroke. For most people, the risk remains low. Your doctor might encourage you to avoid estrogen-containing birth control if you smoke, have high blood pressure, or have other risk factors for blood clots or stroke.

Before you try a new type of birth control, ask your doctor about the potential benefits and risks for you.

Some medications can interfere with birth control

Sometimes when you take multiple types of medications or supplements, they interact with each other. When that happens, it can potentially make the medication less effective. It might also cause side effects.

Some types of hormonal birth control may become less effective when combined with certain medications or supplements. For example, the antibiotic rifampicin can interfere with certain types of hormonal birth control, such as the birth control pill.

Before you try a new type of hormonal birth control or take a new type of medication or supplement, ask your doctor or pharmacist about the risk of interactions.

Condoms come in multiple sizes

Condoms are 85 percent effective at preventing pregnancy, according to Planned Parenthood. But if a condom doesn’t fit properly, it can potentially break or slip off during sex. That can raise the risk of pregnancy, as well as sexually transmitted infections (STIs).

To ensure a good fit, look for a condom that’s the right size for you or your partner. You can determine the size of your penis or your partner’s penis by measuring its length and girth when it’s erect. Then, check the condom package for information about sizing.

You can also find condoms made out of different materials, such as latex, polyurethane, polyisoprene, or lambskin.

Oil-based lubricant can damage condoms

Lubricants (“lube”) cut down on friction, which can make sex more pleasurable for many people. But if you want to use lube and condoms together, it’s important to choose the right product.

Oil-based lubricants (e.g., massage oil, petroleum jelly) can cause condoms to break. If that happens, it can raise your risk of pregnancy and STIs.

That’s why it’s important to use water- or silicone-based lube with condoms. You can find water- or silicone-based lube in many drug stores or sex shops. You can also look for pre-lubricated condoms.

Scientists are trying to develop more birth control options for men

Most birth control options are designed for women.

Currently, the only methods of birth control for men are:

  • abstinence
  • vasectomy
  • condoms
  • the “pull-out method”

Vasectomy is almost 100 percent effective at preventing pregnancy, but it typically causes permanent infertility. Condoms don’t have lasting effects on fertility, but they’re only 85 percent effective at preventing pregnancy. The pull-out method is better than nothing, but it’s still one of the least effective methods of birth control.

In the future, men might have more options. Researchers are developing and testing multiple types of birth control that might work well for men. For example, scientists are currently studying the safety and effectiveness of a male , birth control pill, and birth control injection.

The takeaway

If your knowledge of birth control is limited or outdated, take some time to learn about the options available you. Your doctor or pharmacist can help you find out more, and provide the information you need to make the best decisions for yourself.