It’s time to squash that age-old myth: Your period doesn’t protect you from pregnancy. There are a couple of reasons why. Mainly, some women may bleed when their ovaries release an egg each month, called ovulation, and mistake it for their period. You’re at your peak fertility when you ovulate. So if you have sex during this time, it could actually make you more likely to get pregnant. In addition it’s important to remember that sperm can sometimes survive in the body for up to 7 days after you have sex. This means it may be possible to get pregnant soon after your period finishes if you ovulate early, especially if you have a naturally short menstrual cycle.