Yes, it's possible to get pregnant right after, on, or even just before your period. The likelihood of getting pregnant varies depending on timing and the length of your cycle.
If you're trying to get pregnant, the best time to have sex is just before or during ovulation. If you're not trying to get pregnant, use reliable contraception no matter which day of your cycle it is.
Here's a rundown of your chances of getting pregnant during your period, and on the days before and after it.
Can you get pregnant on your period?
Yes, but it's unlikely. It's possible to get pregnant during your period when:
- You have a very short menstrual cycle (the time from the first day of one period to the first day of your next period).
- You have long periods.
- You were bleeding around the time of ovulation (spotting between periods) and mistakenly thought it was a regular period. If you had unprotected sex at that time, you could conceive.
Here's why you could get pregnant during your period:
Ovulation happens during the middle of your menstrual cycle – anywhere between 7 and 19 days before your period starts. During ovulation, an egg reaches maturity in one of your two ovaries, the ovary releases the egg into your abdomen, and it gets sucked into the nearest fallopian tube, where it can survive for about 24 hours. Conception occurs when an egg and sperm meet in a fallopian tube.
A typical menstrual cycle is 28 days, which usually leaves a good few days between the end of your period and the start of ovulation. But some women have cycles as short as 22 days. If you have a short cycle or long periods, you could ovulate right after your period ends. And because sperm can survive in your reproductive tract for up to five days, if you have sex during your period, it's possible that live sperm will be there when you ovulate, ready to fertilize the egg.
Can you get pregnant right after your period?
Yes. Immediately after your period is still not the ideal time to get pregnant, but you are more likely to conceive at this time than during your period. That's because you're closer to the time when you will ovulate.
Again, two factors can increase your chances of getting pregnant right after your period:
- A short menstrual cycle
- A long period
The shorter your cycle and the longer your period, the more likely it is that you'll be fertile during the last few days of your period or in the days just afterward.
Can you get pregnant right before your period?
Yes, but it's unlikely, and chances are even lower that you could conceive during this time than while you are on your period or right after it. That's because the time you are fertile has probably passed.
However, if you have a menstrual cycle that is shorter than the typical 28 days, there are fewer days between ovulation and the start of your next period during which you are not fertile. That means your chances of getting pregnant right before your period are higher if you have a shorter cycle and lower if you have a longer cycle.
Learn more:
- The best time to get pregnant
- How to get pregnant: A primer
- Ovulation symptoms
- Ovulation predictor kits
- It is very unlikely that you would get pregnant if you have sex the day before your period.
- It's also very unlikely that you would get pregnant during your period or one to two days after it.
- However, it could happen if you have irregular periods or conditions that throw off your cycle.
Whether you're hoping to conceive or trying to avoid unwanted pregnancy, it's helpful to know when you're most fertile versus when you're least likely to get pregnant. For example, you may wonder if you have a high chance of getting pregnant the day before your period.
Although everyone's menstrual cycle is unique, the phases of the cycle are the same, and there are specific times when you're most likely to conceive.
Here's what you need to know about whether or not you can get pregnant the day before your period, and when your most fertile time of the month is.
"It isn't likely that a woman would get pregnant right before her period," says Dr. Jane Frederick, an OB-GYN and reproductive endocrinologist at HRC Fertility, an Affiliate of Keck Medicine of USC.
This is because there's a narrow window of time, about five or six days of the month, where you're most likely to get pregnant. This is due to ovulation, which is when your body releases an egg from your ovary.
Although ovulation only occurs for up to one day, sperm can live in the body for up to five days, which is why your chances of conceiving during the days surrounding ovulation are high.
"This is the fertility window, and it usually occurs about two weeks before your period, in the middle of the menstrual cycle," Frederick says. By the time your period comes up, that egg is long gone.
In fact, if you have a regular cycle and you have unprotected sex the day before your period, you likely don't need to take emergency contraception since the chances of pregnancy are so low, Frederick says.
Chances of getting pregnant based on your cycle
The chances of getting pregnant vary based on where you are in your cycle.
Based on a regular 28-day cycle, here are your chances of getting pregnant surrounding your period, according to Dr. Alice Sutton, an OB-GYN at UC San Diego Health.
Exceptions to this guidance
The big caveat is if you have irregular periods. In this case, you might not know when you ovulate, says Sutton.
Sutton says your period is considered irregular if your cycle is shorter than 21 days, longer than 35 days, or if bleeding lasts longer than seven days. Additionally, the cycle length may vary by cycle, leaving your periods quite unpredictable.
Some situations that can lead to irregular periods are:
- Polycystic ovarian syndrome (PCOS)
- Uterine polyps
- Uterine fibroids
- Stress
- Eating disorders
- Endometriosis
- Side effects of certain medications
Or, Sutton says you might have a condition or infection that results in spotting or bleeding –– but not a true period. In this case, it can be difficult to determine when you're ovulating or having a period bleed.
Sutton says if your periods are irregular and you aren't sure if your bleeding is a true period, the likelihood of getting pregnant is higher.
Another situation where pregnancy right before your period could occur is if you have a short cycle where you might ovulate more frequently, says Frederick. Keep in mind the average cycle is considered 28 days.
However, if your cycle is irregular or on the shorter side, Sutton says it's best to contact your OB-GYN for guidance on whether or not you should take emergency contraception, weighing any pros and cons and taking your medical history into account. Your doctor can help you determine the best course of action.
"If they wanted to be absolutely sure, if they had any doubts about when their period was, or if that bleeding was really a period, their risk-benefit analysis might be different, and they might decide to take [emergency contraception] anyway, just in case," Sutton says.
Insider's takeaway
Your chances of getting pregnant the day before your period are extremely slim if you have a regular, predictable cycle. However, your chances are higher if your cycles are irregular, you have irregular bleeding or spotting, or if you have a short cycle. Everybody is different, and your ovulation time and fertile window may vary.
If you have unprotected sex the day before your period and do not want to get pregnant, contact your doctor for advice on what to do about emergency contraception to determine the best course of action.
Ashley Laderer is a freelance writer from New York who specializes in health and wellness. Follow her on Twitter @ashladerer
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