Can I Be Pregnant If I Just Had My Period?

Chances Before, During, and After Menstruation

Couple lying on bed looking at pregnancy test.
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Whether you are trying to conceive or looking to avoid pregnancy without birth control, timing can make all the difference in the world. One of the more common questions asked by women is whether you can get pregnant if you have had sex immediately before, during, or immediately following your period. 

While the answers are not always cut-and-dry, there are times when pregnancy is more likely and others when the chances are pretty slim.

Chances Immediately Before Your Period

By and large, your likelihood of conceiving right before your period is low. During a typical 28- to 30-day cycle, ovulation will most likely occur between Day 11 and Day 21. When this happens, the egg (ovum) will only be available for conception for 12 to 24 hours.

To this end, the days leading up to your period would be the "safest" if you want to have sex without the risk of pregnancy. It's important to remember, though, that this window of opportunity can vary. Longer cycles will usually have more "safe" days, while shorter cycles will have fewer. As such, you may risk pregnancy if you ovulate later in the cycle or simply miscalculate your "safe" days.

On the other hand, if you are trying to conceive, now would not be the best time to start. You can still enjoy sex but are more likely to conceive if you do so after your period.

Chances During Your Period

The chances are pretty good that you will not get pregnant during your period. Menstruation is the signal that the ovum was not fertilized or implanted, leading to a drop in hormone levels and the shedding of the uterine lining. During this stage in your cycle, your risk of pregnancy will remain negligible until you next ovulate.

With that being said, the risk isn’t necessarily zero. If you have an extremely short cycle, ovulation may occur soon after your period. Given that sperm can live inside you for up to five days, there is a chance—albeit slight—that having sex at the end of your period may lead to fertilization several days later. While highly unlikely, it is still within the realm of possibility.

At the same time, it is important to note that the bleeding you are experiencing may not necessarily be your period. In some cases, it may be implantation bleeding, a very early sign of pregnancy.

Implantation bleeding occurs six to 12 days after fertilization when the embryo attaches itself to the uterine wall. Unlike a regular period, implantation bleeding is typically lighter in color and flow. Mild cramps can also accompany.

Chance Immediately Following Your Period

While you may assume that you are safe from pregnancy in the first few days following your period, you are actually moving into a new fertility window. As such, pregnancy is possible.

Remember that on a 28- to 30-day cycle, the fertility window is usually between Days 11 and 21. If your period lasted for five to seven days, you are already well within shooting distance of that window. As such, if you have sex on Day 6 or 7, any sperm in your body may remain viable right up until the time of ovulation.

At the same time, some women may ovulate before Day 11. It may be a naturally occurring event or one triggered by unexpected fluctuations in hormone levels (often related to stress or strenuous exercise).

With that being said, the availability of an egg doesn’t necessarily confer to pregnancy. For example, if ovulation is abnormally premature, there is a chance that the egg will not have matured enough for fertilization. You may also not have developed enough mucus to move sperm from the vagina to the fallopian tubes.

On top of that, the uterine lining may not have developed enough to support the egg even if it is fertilized.

A Word From Verywell

Whatever the circumstance, your chance of conceiving increases every day following the end of your menstrual bleeding. If you are trying to conceive, you can increase your odds by having sex every other day for the next 14 days.

On the other hand, if you want to avoid pregnancy, you should use at least one method of birth control every time you have sex. This not only includes the days leading up to ovulation but on "safe" days when the risk, however slight, still exists.

In terms of birth control, the rhythm method (also known as the Standard Days Method) is between 80 percent and 88 percent effective in preventing pregnancy. While less than perfect, it offers women an alternative to hormone-based contraception and may be just as effective as condoms if adhered to consistently.

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