What are the chances of getting pregnant after your period

I got off my period on Saturday and I had unprotected sex on Sunday. I’m not sure. Could I be pregnant?

Índice Show

Can you get pregnant on your period?
Can you get pregnant right after your period?
Can you get pregnant right before your period?
When are you more likely to conceive?
Ovulation Calculator
What is an ovulation calculator and how does it help you get pregnant?
Facts about timing
How to know when you’re ovulating
Myth busting
Getting the timing right
What are the chances?
When does preconception health begin?
How to know you are ovulating

Anytime you have unprotected sex, there’s a chance of pregnancy — even during your period or right after your period ends. In fact, right after your period you may be even more likely to get pregnant from unprotected sex because you’ve just started a new menstrual cycle and you could start ovulating at any point.

If you want to avoid getting pregnant, use a birth control method like a condom, the pill, the IUD, or the implant.

If it’s been fewer than 5 days since you had sex without a condom or another birth control method, you can still use emergency contraception to prevent pregnancy.

-Emily at Planned Parenthood

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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

When are you more likely to conceive?

We’re talking about the 'fertile window’ – the days in a woman’s menstrual cycle when pregnancy is possible. The ‘fertile window’ depends on the length of the menstrual cycle, which varies among women.

The ‘fertile window’ is the day an egg is released from the ovary (ovulation) and the five days beforehand. Having sex (intercourse) during this time gives you the best chance of getting pregnant.

Ovulation Calculator

What is an ovulation calculator and how does it help you get pregnant?
This ovulation calculator or ovulation calendar can help you work out your most fertile time. These are the days you are most likely to get pregnant.
It can also estimate your due date if you do become pregnant during your next fertile days.
Others ways to help you work out when you're ovulating:

Notice changes in vaginal mucus
A few days before ovulation, you may notice your vaginal mucus becomes clear, slick and slippery, and feels a bit like egg white.
This is a sign that ovulation is about to happen. It’s the best time to have sex, as sperm travel more easily in this kind of mucus.
Use an ovulation predictor kit
You can use a predictor kit from a supermarket or pharmacy, to test your urine for signs of ovulation. If you start testing your urine a few days before the day you next expect to ovulate, a positive result means you are going to ovulate within the next 24 to 36 hours (one to two days).

Facts about timing
Ovulation is when a mature egg is released from the ovary. The egg then moves down the fallopian tube where it can be fertilised. If sperm are in the fallopian tube when the egg is released, there is a good chance that the egg will be fertilised, creating an embryo, which can grow into a baby.
Pregnancy is technically only possible if you have sex during the five days before ovulation or on the day of ovulation. But the most fertile days are the three days leading up to and including ovulation. Having sex during this time gives you the best chance of getting pregnant.
By 12-24 hours after ovulation, a woman is no longer able to get pregnant during that menstrual cycle because the egg is no longer in the fallopian tube.

There’s almost no chance of getting pregnant if you have sex before or after the fertile window (but if you’re not trying to get pregnant, don’t rely on this – contraception is your best option!).

How to know when you’re ovulating
Knowing when you ovulate can help you plan for sex at the right time and improve your chance of getting pregnant. You can keep track of your menstrual cycles on a chart, in a diary, or on a free period-tracker app on your smartphone.
To work out the length of your menstrual cycle, record the first day you start bleeding (first day of your period). This is day 1. The last day of your cycle is the day before your next period begins.

What is a ‘menstrual cycle’ and a ‘period’?
Some people think the ‘menstrual cycle’ and a ‘period’ are the same thing.
A period is when you bleed (or menstruate).
A menstrual cycle starts on the day when a period starts (day 1) and ends the day before the next period. A cycle’s length is considered normal if it’s between 21 and 35 days. They can vary between women and from one cycle to the next.
Working out your ‘average’ menstrual cycle length
If your menstrual cycles are different lengths (most women’s cycles are) you can work out your average cycle length.
The number of days in a woman’s menstrual cycle can vary month to month. Periods are not always regular. It can be useful to work out an ‘average’ cycle length, based on the length of three menstrual cycles, to estimate when you’re most likely to be ovulating.
If you add the number of days in three cycles and divide the total number by three, it gives you your average cycle length.
Example
Sarah tracked her last three menstrual cycles by counting the time from the first day of one period, to the day before the next period.
Cycle 1 was 28 days; Cycle 2 was 32 days; Cycle 3 was 27 days
28 + 32 + 27 = 87
87 divided by 3 = 29
So the average length of Sarah’s menstrual cycles is 29 days.
Working out your most fertile days
When you know your average menstrual cycle length, you can work out when you ovulate.
Ovulation happens about 14 days before your period starts.
- If your average menstrual cycle is 28 days, you ovulate around day 14, and your most fertile days are days 12, 13 and 14.
- If your average menstrual cycle is 35 days ovulation happens around day 21 and your most fertile days are days 19,20 and 21.
- If you have shorter cycles, say 21 days, ovulation happens around day 7 and your most fertile days are days 5, 6 and 7.
Your most fertile days are the three days leading up to and including the day of ovulation.
Some women have very irregular cycles or find it difficult to work out an average cycle length. This can make it hard to work out when ovulation happens. If it’s all too hard, having sex every 2-3 days covers all bases and improves your chance of getting pregnant.

Myth busting

MYTH

A woman can get pregnant any time of the month.

FACT

A woman can only get pregnant on a few days during her menstrual cycle.

Why?

Because eggs and sperm only live for a short time:

Sperm live for around five days.
Eggs can only be fertilised for around 24 hours (one day) after being released from the ovary.

Eggs and sperm need to come together at the right time for fertilisation to happen to create an embryo.

Getting the timing right

If you're trying to get pregnant, timing is everything. Dr Karin Hammarberg explains how to work out when you are ovulating and the right time to have sex to improve your chance of pregnancy.

What are the chances?
Having sex as close as possible to the time of ovulation increases the chance of pregnancy.
If a woman has sex six or more days before she ovulates, the chance she will get pregnant is virtually zero.
If she has sex five days before she ovulates, her probability of pregnancy is about 10 percent.
If she has sex on the day of ovulation, or the two days before, the chance of getting pregnant is around 30 percent.
These are average figures and depend on a woman’s age.

When does preconception health begin?

Professor Sarah Robertson, Director of Robinson Research Institute, University of Adelaide, highlights the key time before pregnancy that your health is most important to ensure your child has the best start to life.

How to know you are ovulating

Kerry Hampton, a registered nurse and fertility specialist, discusses the importance of fertility awareness, and how to determine your fertile window to improve your chances of conceiving.

References
- American Society for Reproductive Medicine, Optimizing natural fertility, https://www.reproductivefacts.org/news-and-publications/patient-fact-sheets-and-booklets/documents/fact-sheets-and-info-booklets/optimizing-natural-fertility/
- Berglund Scherwitzl, et al. (2015). Identification and prediction of the fertile window using Natural Cycles. The European Journal of Contraception and Reproductive Health Care, 20(5), 403-408. doi:10.3109/13625187.2014.988210
- Ecochard, R., et al. (2015). Self-identification of the clinical fertile window and the ovulation period. Fertility and Sterility, 103(5), 1319-1325.e1313. doi: http://dx.doi.org/10.1016/j.fertnstert.2015.01.031
- Pfeifer, S., et al. (2017). Optimizing natural fertility: a committee opinion. Fertility and Sterility, 107(1), 52-58. doi: 10.1016/j.fertnstert.2016.09.029
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- Stanford, et al. (2002). Timing intercourse to achieve pregnancy: current evidence. Obstetrics and Gynecology, 100(6), 1333-1341.
- Stephenson, J., et al. (2018). Before the beginning: nutrition and lifestyle in the preconception period and its importance for future health. The Lancet, 10.1016/S0140-6736(18)30311-8 doi: 10.1016/S0140-6736(18)30311-8
- Vélez, M. Pet al. (2015). Female exposure to phenols and phthalates and time to pregnancy: the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. Fertility and Sterility. doi: 10.1016/j.fertnstert.2015.01.005
- Verón, G. L., et al. (2018). Impact of age, clinical conditions, and lifestyle on routine semen parameters and sperm kinematics. Fertility and Sterility, 110(1), 68-75.e64. https://doi.org/10.1016/j.fertnstert.2018.03.016
- Waylen, A. Let al. (2009). Effects of cigarette smoking upon clinical outcomes of assisted reproduction: a meta-analysis. Hum Reprod Update, 15(1), 31-44.
- Zenzes, M. T. (2000). Smoking and reproduction: gene damage to human gametes and embryos. Hum Reprod Update, 6(2), 122-131.