There are some pretty common myths about how women can get pregnant, whether by accident or intentionally. For example, getting pregnant by sitting on a toilet seat. While most college students probably realize the absurdity of this myth, there are others that seem legit. This may be because some are so similar.

A common myth about preventing pregnancy is if you have sex while a woman is on her period, she can’t get pregnant. While it might not be a common occurrence, this is not a practical preventative method. The egg is fertilized while it is in its descent down the fallopian tube. Sperm can live up to five days after being ejaculated into the vagina, and some women can become fertile four days after the beginning of their period.

This means that another egg has been released from one of the ovaries. This is similar to the myth of using the ovulation cycle to prevent or ensure pregnancy. Women have varying cycles on an unseen level.

Ovulation at around 14 days after the start of a period is not a rule for most women. As mentioned above, fertility can occur in as little as four days. Therefore, this is not a reliable method to predict when a couple can conceive or when it can prevent pregnancy.

The withdraw or pull-out method is when a man removes his penis from the vagina prior to ejaculation. This seems like it would work, except for that a little bit of fluid that comes out of the penis during stimulation. This fluid has a chance of carrying sperm in the urethra from a previous ejaculation. And we know how long sperm can possibly last.

It doesn’t require much sperm for a woman to become pregnant, either. In the end, only one little guy is required- or allowed- to fertilize, but because millions are in each ejaculation, there could be hundreds left in the urethra. And there is always a chance some could make it to the egg.

Positioning after or during sex does not have an effect on whether a couple gets pregnant. To improve the chances of conceiving, some people believe that if a woman inverts herself it will help the sperm find its way. Aside from lying down for a few minutes after sex, positioning will have no bearing on pregnancy chances. Additionally, positions, such as standing, will not prevent a pregnancy either.

When there is a chance of becoming pregnant in any of the above scenarios, the idea that getting pregnant can’t happen from having sex once is easily dismissed.

In fact, there is even a greater chance of getting pregnant given the amount of time that a woman is fertile during a cycle and how long sperm has to find the egg.

Kourtney Bailey can be reached at [email protected].