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Can You Get Pregnant on Your Period?

Is it possible to get pregnant during your period?

Yes, although the chance is low for most people. Pregnancy can only happen during the fertile window: the six days ending on the day of ovulation (Wilcox et al., NEJM 1995). Sex during a period can lead to pregnancy when ovulation comes early enough that sperm are still alive when the egg is released.

How long does sperm live inside the body?

Sperm can survive 3 to 5 days in the reproductive tract, while an egg lives 12 to 24 hours after ovulation (Office on Women's Health). That gap is what makes period sex a possible, if unlikely, route to pregnancy.

When is the chance higher?

Short cycles

In a 24-day cycle, ovulation may happen around day 10. Sperm from sex on day 5 or 6 — still the last days of some periods — can survive until then.

Timeline of a 24-day cycle where the fertile window begins at the end of the period

Long periods

If your period lasts 7 days or longer, the final days of bleeding can come close to an early fertile window.

Irregular cycles

When ovulation timing varies, it can come earlier than expected in any given month.

Bleeding that isn't a period

Spotting around ovulation or other bleeding can be mistaken for a period. Sex on those days can fall inside the fertile window.

Does this mean period days are "safe" days?

No. No day of the cycle can be called completely safe based on a calendar alone, because ovulation can shift. If you want to avoid pregnancy, use a contraceptive method and talk to a doctor or nurse about the options that suit you.

What if I think I might be pregnant?

If your next period is late, take a home pregnancy test. The FDA suggests testing one to two weeks after a missed period for the most reliable result and repeating the test if it is negative but your period still hasn't come. Read more: why is my period late?

How tracking helps you understand your fertile days

Knowing your average cycle length shows whether your cycles are short enough for the fertile window to start near the end of your period. In Oona — Period Tracker & Calendar, the estimated fertile window updates as you log each period. It is a tracking estimate, not a way to prevent pregnancy.

Oona is a tracking app. It is not a contraceptive method and not a diagnostic tool.

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