Can You Get Pregnant if You Have Sex During Your Period?

Can you get pregnant on your period if you have unprotected sex? Despite what you may have heard or been told, the answer is yes. You’re less likely to conceive during this time, but it’s not impossible.

We talked with Ob/Gyn Christine Oak, MD, about the risk of getting pregnant during your period. Dr. Oak explains why it happens — and what you need to know to protect yourself.

Can you get pregnant on your period?

While the chances are lower, getting pregnant during your period is still a possibility. Having unprotected sex at any point in your cycle can lead to pregnancy, including during menstruation.

Why it’s possible

While ovulation (when your body releases an egg) is typically your most fertile time, your cycle can shift from month to month. And even if your cycle is stable, that doesn’t mean it looks like the “average cycle” you learn about in sex ed.

These normal, natural fluctuations make it possible to get pregnant on your period.

Another factor? Sperm survival.

Sperm can live in your reproductive tract for up to five days after you have sex. So, sperm may still be present in your body when you ovulate, especially if you ovulate earlier than usual.

What are the odds of getting pregnant on your period?

It’s certainly possible to get pregnant if you have unprotected sex during your period — but it’s not probable.

“During your period is most likely the lowest risk timeframe to have unprotected sex if you want to avoid pregnancy,” Dr. Oak states. “But if you truly don’t want to get pregnant, there are much more reliable ways to prevent pregnancy than timing up sex to happen on your period. There’s always a risk of pregnancy if you’re not using contraception.”

Risk factors

You’re more likely to conceive during your period if you:

• Have short cycles (less than 28 days): If you have a shorter-than-average menstrual cycle, a small number of sperm could still be hanging around when you ovulate, even though you had sex during your period.
• Have a long period: The longer your period lasts, and the later in your period you have unprotected sex, the more likely you are to bump up against your ovulation window. Long periods are common if you’re living with high levels of stress, take certain medications or have a condition like endometriosis, uterine polyps or polyendocrine metabolic ovarian syndrome (PMOS) (formerly, polycystic ovary syndrome, PCOS).
• Ovulate earlier than expected: Some studies suggest that only about 30% of women ovulate between days 10 and 17 of their cycle. Some ovulate earlier, some later. If you ovulate early, you can get pregnant by the sperm waiting around for their opportunity to fertilize an egg.
• There’s a sudden change in your cycle: “Things like weight loss, weight gain, stress, medications and uterine fibroids can cause a sudden change in your menstrual cycle, even if you’re normally very regular,” Dr. Oak says. “So, never say never.”
• You mistake spotting for your period: “When you have your period, your entire uterine lining is shed, including any unfertilized eggs,” Dr. Oak explains. “But you can have vaginal bleeding that isn’t the same as a period. Not all bleeding clears out unfertilized eggs.”

What about right after your period?

Having unprotected sex right after your period ends is risky because your fertility starts ramping up around that time. Having unprotected sex during the days right after your period could actually put you even closer to ovulation, boosting your odds of getting pregnant.

What about right before your period?

While you tend to be least fertile right before your period, it’s important to remember that your menstrual cycle can change on a dime. A bad cold, a sports injury or a stressful situation could be all it takes to throw your hormones — and your cycle — out of balance.

In other words, you can’t count on what’s “right before” your period this month being the same next month.

Preventing pregnancy while on your period

The only way to prevent unwanted pregnancy — whether you have sex on your period or not — is to abstain from sex or use reliable birth control methods correctly, Dr. Oak emphasizes.

If you take birth control pills, that means taking them every single day at the same time. If you rely on the birth control shot (Depo-Provera®), keep your appointments. If you use condoms, be sure to use them properly to avoid a tear.

And to be extra careful (and avoid sexually transmitted infections), use more than one type of birth control.

“It doesn’t hurt to use a condom in addition to birth control pills, IUDs or other methods,” Dr. Oak suggests. “And it can help to ensure you’re really protected.”

If pregnancy isn’t your goal, your period isn’t a dependable form of birth control. Talk with a healthcare provider, like an Ob/Gyn or primary care provider, about the best birth control for you.