Can You Become Pregnant Being Menstruating?

You can get pregnant during menstruation? This question is very common and can be answered in short or long form. Let's start with the short form.


Everyone knows that to get pregnant there must be a meeting of a sperm with the egg, a fact that can only occur during the woman's fertile period. Therefore, it makes sense to imagine that it is impossible that the woman becomes pregnant at the time of menstruation, since menstruation is not part of the fertile period of the cycle.

The above reasoning is correct, but the conclusion is wrong. It is indeed possible to get pregnant if you have unprotected sex during your period. It is not common or very likely, but by no means impossible.

So the short and simple answer to the question that gives rise to the title of this article is: yes, it is possible to become pregnant and is menstruating.

Let's the long answer, which will explain why, despite illogical seem, it is possible to get pregnant during menstruation. Throughout the text we will try to answer and explain the following three questions:

• 1. Can I get pregnant standing menstruating?
• 2. Can I get pregnant soon after the end of the menstrual period?
• 3. Can I get pregnant just before the start of the next period?

Before we move on to the explanations, let's talk superficially about the fertile period and fertilization, which is when the sperm meets the egg.

In this article we will talk of the fertile period just enough to be able to explain about the risks of getting pregnant during menstruation. If you are looking for more detailed information about the fertile period, visit the following links:

• Calculating fertile period
• Fertile period for pregnant
• Menstrual cycle

Attention, this text makes sense only for women who do not use hormonal contraceptives. If you use birth control pill, there is no risk of pregnancy throughout the menstrual cycle, even at the time of break from the pack.


It is unlikely, but there are special situations where this becomes possible. These are the cases that lead a woman to get pregnant when she has unprotected sex during menstruation.

To understand how this is possible, we will explain very simply 4 concepts:

• Duration of the menstrual cycle
• Time of ovulation
• Duration of menstruation
• Fertile period

Duration of the menstrual cycle

The menstrual cycle also called ovulatory cycle starts on the first day of menstruation and ends the day before the new period. That is, the cycle begins when menstruation falls in a given month and ends as soon as menstruation back the next month.

For most women, the menstrual cycle takes about 28 to 35 days. But some people may have shorter cycles or longer than this average. Very short or very long cycles are especially common in adolescents and in women who are near menopause.

There are women who have regular menstrual cycle as well, with stable duration over the months, while others have irregular cycles, with durations ranging from month to month.

Ovulation time

Regardless of the size and cycle regularity, ovulation typically occurs between 12 and 14 days before the end of the cycle. This means that a menstruating woman after a 28 day cycle, ovulated around the 14th day. Already a woman with cycle 40 days ovulated around the 26th day, while a woman with a short cycle of 22 days ovulated around the 8th day cycle.

As we will see later, it is women who have short menstrual cycle that may be technically fertile during menstruation.

Duration of menstruation

The period itself usually lasts 3 to 7 days. The blood that the woman loses during the menstrual period is actually the inner lining of the uterus is falling, spurred by hormonal changes of the end of the ovulatory cycle. It is important to note that the fact that you are menstruating does not mean that your hormonal cycle is stopped waiting the period end. Rather, the hormonal cycle leading to the next ovulation was restarted on the first day of menses. This means that on the 7th day of your period, your body is already on the 7th day of the ovulatory cycle.

Fertile period

The last information we need to know to close our reasoning is the concept of fertile period. Called fertile period the time it is possible that unprotected sexual intercourse generate a pregnancy.

When the woman ovulates, its ovum is viable for only be fertilized for 12 to 24 hours, going to a maximum of 36 hours in some cases. This does not mean, however, that the fertile period lasts only 12 to 36 hours. Sperm can survive in the female reproductive system for 3 to 5 days (there are some that remain viable for up to 7 days, but this is not common). This means, therefore, that the fertile period comprises 5 days of life of sperm over the 24 hours of the egg, that is, the fertile period is usually 6 days in total.


If you understand all that has been explained so far, you probably imagine why a woman can get pregnant having intercourse during menstruation. Let us conclude our explanations with some examples.

Imagine a woman with a short menstrual cycle, only 24 days. If your cycle is 24 days, this means that ovulation occurs around the 10th day cycle. As we already know that sperm usually stay viable for 5 days inside the woman's body and the egg survives for 24 hours, this means that any unprotected sexual intercourse that occurred between the 5th and the 11th cycle can lead to a pregnancy. So if menstruation this woman has a duration of 5 to 7 days, it is perfectly possible that she becomes pregnant if you have relations in the last 2 days of their menstrual cycle (5th to 7th day cycle).

Therefore, the shorter the menstrual cycle and longer is the time of menstruation, the greater the chances of a woman becoming pregnant during your period. Women with shorter menstrual cycle than 24 days and time period of greater than 5 days are those most at risk.

It is important to remember that most women do not have as short cycles or periods so long. A woman with menstrual cycle of 28 days and 5 days of bleeding time can not get pregnant during menstruation because their ovulation occurs around the 14th cycle and the period lasts only until the 5th day. Even if this woman has relationships on the last day of your period, the sperm only IRAM survive until the 10th cycle. When ovulation get there by 4 days there will be more viable sperm to fertilize the egg.


It is very unlikely, but not impossible. If a woman has an extremely short cycle of about 20 or 21 days duration, ovulation occurs around the 6th day cycle, allowing sexual intercourse on the first day of menstruation can still provide viable spermatozoa when ovulation.

This is extremely unusual, but, again, it is not impossible.


As seen, albeit low, the closer to the end of the period, the greater the risk of an unprotected intercourse generate a pregnancy. Therefore, a sexual relationship that occurred after the end of menstruation has more risks than a relationship that has occurred within the menstrual period. And this risk increases exponentially as the days go by. A relationship has occurred 3 days after the end of the period has a higher risk compared to two before occurred, which in turn has more risk that a relationship occurred the next day after menses.

Again, the shorter the cycle and longer the time period, the greater the risk of pregnancy when it has unprotected intercourse after the end of the menstrual period.


This is the most unlikely event of all. For sexual intercourse that has occurred 1 or 2 days before the descent of the light period to a pregnancy would require the simultaneous occurrence of several improbable situations, such as an extremely early ovulation and sperm high quality, which generates viable spermatozoa of at least 7 days. It is very unlikely.

Therefore, the safest period to have unprotected intercourse takes place in the time interval between the moment that the egg-degenerates and becomes infeasible (about 24 to 36 hours after ovulation) and the beginning of the next menstrual period. This means a withdrawal period of 10 to 12 days in women with ovulatory cycle around 28 days.

The problem is that most women do not know when ovulated and can not be sure of the exact day that the next period will come. Thus, it is very difficult to know when these 10 days safer to have sex without protection.