It’s hard to know when you're least likely to become pregnant. Having sex when you think it’s a "safe" time (called fertility awareness) can lead to an unplanned pregnancy.

Pregnancy is most likely to happen about halfway between periods, during ovulation (when the ovaries release an egg). The amount of time between periods isn’t very exact when you’re younger than 21, making the halfway point hard to predict. You can also be fertile (able to get pregnant) days before and after you ovulate.

What Are Better Methods of Birth Control?

Couples having sex should use a reliable birth control method that works better to help prevent pregnancy, like:

• an intrauterine device (IUD)
• birth control pills
• the patch

What Else Should I Know?

Sexually transmitted diseases (STDs) are another concern if you're sexually active. They can spread through vaginal, anal, or oral sex; using fingers; or with other sexual contact. To help prevent STDs, use condoms each time you have sex. The only way to fully prevent STDs and pregnancy is to not have sex.

How Can I Find Out More?

To learn more about how to avoid pregnancy and STDs, talk with your doctor. You can also go to a health clinic like Planned Parenthood.