Your Chances of Getting Pregnant Right Before Your Period

Whether you're trying to conceive or want to avoid pregnancy, the timing of sexual intercourse is important. Conception can only occur during ovulation, which usually happens about midway through your menstrual cycle.

It's much less likely that you'll get pregnant by having sex immediately before or during your period. That said, if you have short or irregular menstrual cycles, there's a small chance you can conceive near your period. Here's what to know.

How Do You Get Pregnant?

During each menstrual cycle, the ovaries release a mature egg in a process called ovulation. The egg travels down the fallopian tube, where it lives for 24 hours. Sperm, on the other hand, can survive up to five days in the reproductive tract.

Since days-old sperm can fertilize a newly released egg, you could get pregnant by having sex on the day of ovulation and five days beforehand. These six days are known as your "fertile window."

The fertile window usually happens about halfway through your menstrual cycle, but the timing can vary from person to person and even month to month. So while you're more likely to conceive during other times, there's a small chance you can get pregnant around your period.

Can You Conceive Right Before Your Period?

By and large, your likelihood of conceiving right before your period is low. That's because you've probably already ovulated, and the released egg is no longer viable, as it only lives for about 24 hours.

That said, there's a slight chance of pregnancy if you tend to ovulate later in your cycle, or if you simply miscalculate the timing of your next period.

The bottom line is that if you're trying to conceive, you probably don't need to have intercourse right before you expect your period. You can still enjoy sex, of course, but you're much more likely to get pregnant if you try again after your period.

Can You Get Pregnant During Your Period?

The chances are pretty high that you won't get pregnant from having sex during your period. Menstruation happens when the egg isn't fertilized, leading to a drop in hormone levels and the shedding of the uterine lining. Even if a sperm made it to an egg during your period, which isn't likely, the uterine lining wouldn't be ready for implantation.

However, the odds of conception during your period aren’t zero. If you have a very short cycle, you might ovulate soon after your period. Given that sperm can live inside you for up to five days, having sex at the end of your period may lead to fertilization in the days following it.

One study found that the odds of conception start to rise on day seven of your cycle—just a week past your first day of bleeding.

Can You Get Pregnant Immediately After Your Period?

While you may assume that your chances of getting pregnant are slim in the first few days after your period, you're actually moving into a new fertile window at this time.

Researchers have found that the probability of conception jumps starting a week after your period begins, and it rises steadily after that, peaking about midway through the cycle.

Your odds of getting pregnant right after your period are higher if you have a short menstrual cycle, since ovulation would occur soon after your period ends. People with a 23-day menstrual cycle, for instance, have a 9% chance of ovulating on day 10 of their cycle. That means they're fertile—able to get pregnant—starting about five days after the start of their last period.

Can I Be Pregnant If I Had My Period?

Getting your period is a sure sign you're not pregnant. It's even more reliable than an early negative pregnancy test, which has the potential of being false. When your period comes, you're shedding the uterine lining that built up in case you did conceive.

That said, it's possible to have some bleeding even if you are pregnant. Some people see light spotting about six to ten days after ovulation. Called implantation bleeding, it occurs when an embryo implants itself in the uterine lining.

If you got negative pregnancy test results but think you might be expecting, take another test a few days after the first one, and contact your health care provider with any questions.