It’s possible to get pregnant if you have sex during your period. This is because of ovulation, the time each month when ovaries release an egg.

What Happens With Ovulation?

After the egg is released, it travels to the lining of the uterus. If you have sex, sperm can “meet” or fertilize the egg, which becomes a fetus. If the egg isn’t fertilized, the uterus lining breaks down and bleeds. This is a period.

With ovulation, the body is getting ready for a possible pregnancy, so it’s when you're most likely to get pregnant if you have sex.

How Can I Get Pregnant While I Have My Period?

Ovulation often happens about 2 weeks before your period starts. But it can happen at other times, like soon after your period.

After sex, sperm can live in the female reproductive system for up to 3 days. So, for example, if you have sex near the end of your period and ovulate in the next few days, the sperm could still fertilize the egg.

Ovulation itself can cause bleeding, which tends to be lighter than a period. This means you could have sex thinking you have your period, but you’re really ovulating.

What Else Should I Know?

Having unprotected sex at any time is risky. Along with the chance of getting pregnant, you could also get a sexually transmitted disease (STD). This is an infection that can spread through vaginal, oral, or anal sex; by using fingers; or with other sexual contact. And having sex during your period can make it easier for some STDs to spread.

The only way to fully prevent STDs and pregnancy is to not have sex.

If you do have sex, use a condom each time — it’s the best way to prevent infections. The best way to prevent pregnancy is to use a second method of reliable birth control, like birth control pills, the patch, or the ring. 

Talk with your doctor about what type of birth control is best for you. You can also visit a health clinic like Planned Parenthood.