Whether you want to have a baby right now or you’re not yet ready yet, understanding your menstrual cycle helps you to make an informed decision about conception. That said, not every woman follows a stable, set cycle. While you aren’t likely to get pregnant while menstruating, it is still possible.
Your monthly cycle starts with the first day of menstruation. According to the U.S. Department of Health and Human Service’s Office on Women’s Health, the average period lasts for five days. Some women menstruate for longer or shorter times, depending on their monthly cycles. For most women, the bleeding stops by day seven. Around this time follicles -- or fluid-filled pockets -- are developing in your ovaries. Each follicle holds an egg. When the follicle is mature it bursts and releases its egg. Not every follicle matures at the same time. Typically, only one egg is ready to be fertilized during any given cycle. Day 14 finds the egg ready to come out of the ovary -- also known as ovulation.
As the egg moves down the fallopian tube on its way to the uterus, you can get pregnant. If fertilization doesn’t happen, your hormone levels will drop and you’ll menstruate again. If you have a regular 28-day cycle, you ovulate around day 14 as the egg is released. This is typically seven or more days after the end of your period.
Women with shorter or longer cycles ovulate on other days. Subtract 14 days from your overall cycle length to calculate ovulation, the University of Maryland Medical Center advises. For example, if you have a 21-day cycle, you will most likely ovulate on day seven. This may mean that you ovulate within days of your period instead of a week or more later.
While it’s much less likely that you’ll get pregnant during your period than at mid-month, a shorter cycle combined with long-living sperm can do the trick. Sperm can live for up to five days inside of your reproductive tract, according to the American Pregnancy Association. Your body’s hormone levels typically won’t allow you to actually ovulate while you are menstruating. In the case of a short cycle, you may ovulate a few days after your period ends. This means that sperm released during sex toward the end of your period can live until ovulation, resulting in pregnancy.