A woman's ovulation cycles can vary, so it's statistically possible you could become pregnant while on your period. While pregnancy is less likely in the earlier days of your period, the chances increase in the later days.

Can menstruation get you pregnant?

Technically, people can get pregnant at any time during their menstrual cycle, though it is much less likely during their period. A person is most likely to get pregnant in the middle of their menstrual cycle. This phase is called the fertile window.

Can sperm survive in menstrual blood?

Sperm can survive in a woman's reproductive system for up to 5 days whether the woman is menstruating or not. Thus, even if a woman has sex during her period, sperm from ejaculation may remain inside her reproductive system and may fertilize the egg if ovulation occurs.