Can You Get Pregnant While You’re on Your Period?
You already know that your period is when the uterus sheds the lining that it grows every month to support a possible pregnancy. So it would make sense that it would be impossible to get pregnant during this time, right? Wrong. While it's fairly rare, it is definitely possible to get pregnant while you're on your period. Here are a few common scenarios.
You're freshly out of puberty or you're showing signs of menopause or perimenopause.
When you are going through or finishing up the puberty process or preparing for the end of the child-bearing years, your hormones are doing all kinds of odd things. This means that your periods may get irregular. This makes it much harder to predict fertile and infertile times during your cycle. Plus, your cycle length and timing of ovulation can become erratic. If you happen to ovulate during your period, there is a chance that it could lead to a pregnancy.
Your periods are long.
The average period lasts three to five days, according to the Office on Women's Health. However, that's just an average, and many women have longer or shorter periods. If you tend toward the longer side, your body may start preparing for ovulation while you're still experiencing bleeding in those last couple of days. This means that sperm could have what they need to survive in the body a few days until ovulation occurs. So even though you had sex while on your period, the fertilization happened days later.
Your cycles are short.
If you have a shorter cycle, the number of infertile days is fewer than what a woman with a longer cycle would have. This makes it easier to get pregnant on your period. Consider this scenario: A woman has a cycle that is 22 days long. That means that her ovulation is likely around day 7 to 11. If her period is the usual 4 days long and she has sex on the 4th day, the sperm could live up to 5 days after. This would put the sperm possibly viable in the ovulation window.
Bottom line: If you're concerned about getting pregnant during your period, it's a good idea to use a backup method.