The Chances of Getting Pregnant on Ovulation Day Without Protection

Updated October 10, 2022
Young woman holding home pregnancy test

If you have tried to get pregnant, you are probably familiar with every possible aspect of your menstrual cycle. Maybe you have marked your cycle days painstakingly on your calendar for months. Maybe you are keeping the ovulation kit companies in business. Maybe you know what your temperature has been every single morning since last fall.

If this is you, then you know you are most likely to conceive if you have sex during your six-day fertile window than on any other day during your menstrual cycle. But what are the chances of getting pregnant on ovulation day without protection? Careful monitoring of ovulation and timing of intercourse is essential whether you want to get pregnant or are trying to avoid it.

Chances of Pregnancy Around Ovulation Day

The lifespan and survival of the egg and sperm are the factors that determine your best days of fertility (or fertile window) in the first half of your cycle. You conceive when there is a viable egg and sperm available.

When you have sex on the day you ovulate, you have a new egg ready to be fertilized by fresh sperm. The chances of pregnancy during ovulation are high. Your chances are also high on the day before ovulation. Most women have a total of six fertile days in a normal menstrual cycle, including the day of ovulation. This means if you have intercourse on any of the five days leading up to the day of ovulation, you can still get pregnant even if you avoid sex on the day you ovulate.

Chances of Conception

You've timed intercourse perfectly and now you're thinking "I had sex on my ovulation day, so I'm sure that I got pregnant!" Right?! Well, maybe. The following are the chances of conception for each fertile window day:

Days Before Ovulation Day

Chance of Conceiving
Five 4%
Four 17%
Three 23%
Two 29%
One 34%
Ovulation Day 33%
One day past ovulation 11%

The Fertile Window Around Ovulation Day

A 2014 review by the Global Library of Women's Medicine (GLOWN) notes the egg survives for only about 24 hours after you ovulate. Therefore, intercourse within that 24-hour window gives you the best chance of fertilizing a viable egg. Based on the review, sperm, however, can survive in your reproductive tract for days.

Sperm maintains its best fertilizing function for 72 hours on average but can be still viable up to five days after intercourse. So, if you have sex on any one of your five other fertile days, you may still get pregnant on the day you ovulate, since the sperm can still be viable and "waiting" for the egg.

How to Track Ovulation for Conception

You can track signs of fertility to try to predict your day of ovulation to increase your chance of conception. Everyone's fertile window can vary, and the following methods can help you learn your body's timing.

Ovulation Calculator

Many websites offer ovulation calculators to help you understand your cycle and when you are most likely to ovulate and menstruate. These calculators can also help determine your due date when you conceive. If you have irregular cycles, you might have more difficulty pinpointing ovulation; therefore, your chance of conceiving each cycle might be lower than the average.

Basal Temperature

If you measure your temperature at the same time every morning, it should read relatively the same. That number is your basal body temperature. If you check this reading every day for a few months, you should notice an increase in temperature for a few days after ovulation. So, once you get to know your cycle and body, you can use this measurement to predict when you will ovulate.

You can use a regular thermometer, but a basal thermometer measures your temperature to a much higher degree of specificity, and so by using one you will be able to see more clearly when your temperature rises.

Ovulation Kits

Much like a pregnancy test, ovulation tests measure hormones in your urine. These tests measure the amount of luteinizing hormone (LH) which is released at much higher levels a day or two before ovulation. If your LH measures high, that could mean you're about to ovulate and you should plan to have intercourse over the next few days if you are trying to conceive.

Vaginal Discharge

Vaginal discharge changes throughout the cycle. According to the American Pregnancy Association, after your period stops, you may notice very little discharge. Then it usually becomes thick and sticky. Around ovulation, your vaginal discharge should increase in amount and become thinner and stretchy, much like the consistency of egg whites.

Ovulation Pain

Some people experience minor pain when an egg is about to exit the ovary, or during ovulation. This is called Mittelschmerz. About one in five women experience this pain, which can be quite subtle. Pay attention to your body around the time you think you might be ovulating and see if you notice it.

Cervical Changes

At the time of ovulation, your cervix will get softer, move higher and feel wetter. These changes are to allow for easier passage of sperm. It can be difficult to check your own cervix, but if you feel up to it, check it every day or every other day with a clean finger and you may notice the change.

How Often Should You Have Sex During Ovulation?

Your best chance of conceiving, in general, occurs if you are regularly having sex. The ASRM recommends having intercourse every one to two days during the six-day fertile window that ends on the day on which you think you ovulate.

Pregnancy rates are highest in couples who have sex daily or have sex every other day when actively trying to conceive. To be certain you're having sex when you're most fertile, you should begin attempting to conceive shortly after your period ends and have sex every other day or at least every third day. This would help increase your chances of conception during ovulation.

How Much Is Too Much?

It is recommended that you have sex once a day at the most; however, per the ASRM, sex every other day is optimal. If you have sex too often, it can reduce the sperm count and the quality of the sperm. It will take some time for sperm to replenish after ejaculation as well.

Avoiding Pregnancy Around Ovulation Days

Using the facts about ovulation and the most fertile days of the cycle and tracking your fertility signs can help you know when to avoid intercourse or to use protection during your cycle to avoid getting pregnant. However, ovulation tracking is not generally considered an effective method of birth control and most health providers recommend additional methods.

Understanding your fertility on the day of ovulation and the five days preceding can help you increase your chances of conception if you are trying to get pregnant, and can also prove useful if you are trying to avoid pregnancy. It can feel very frustrating to wait for a positive pregnancy test. Always feel free to reach out to your doctor to discuss your concerns.

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The Chances of Getting Pregnant on Ovulation Day Without Protection