How Long Does Ovulation Last?

The best time to have sex to conceive varies

If you are trying to get pregnant, it's helpful to know when you ovulate. Ovulation is when an egg is released from an ovary. Your ovulation period lasts for 12 to 48 hours.

However, since sperm are hardy and can survive in the female reproductive tract for around 72 hours, you can get pregnant anywhere from five days before you ovulate to a day after you ovulate. This period is known as your fertile window. Timing sex during this six-day fertile window makes you significantly more likely to conceive, according to research.

how long does ovulation last
Illustration by Katie Kerpel. © Verywell, 2018.

Tracking Ovulation to Find Your Fertile Window

There are many methods of tracking and predicting ovulation so you can try to figure out when you are most fertile. An ovulation day calculator may provide an estimate, but isn't always the most accurate of methods, especially if you have irregular periods.

Some ways to try to pinpoint your ovulation period at home include over-the-counter ovulation predictor kits, body basal temperature charting, and checking for fertile cervical mucus.

Ovulation predictor kits increase your chance of getting pregnant by 40%, according to a review of research. Each kit comes with five or so test strips or sticks, and manufacturers typically recommend you test your urine for several days leading up to your suspected ovulation day. This makes this method can potentially costly, especially if you have somewhat irregular periods and you have to test for many days (or months) on end.

Among no-cost home ovulation-tracking methods, checking the texture of your cervical mucus may work best. According to research, people who had sex when they had slippery, egg-white-like cervical mucus (associated with your ovulation period) were two to three times more likely to conceive than those who had scant or absent mucus secretions (typical at the very start of your menstrual cycle).

Determining the Best Time to Have Sex to Conceive

Unfortunately, there's no completely accurate method to detect that you are about to ovulate. It's possible for an ovulation predictor kit, body temperature charts, and cervical mucus patterns to all indicate a slightly different ovulation day.

In a study of people with regular, 28-day cycles, ovulation occurred most commonly (in 27% of people) on day 15 after the start of the last menstrual period (LMP), followed by day 16 LMP (21%) and day 14 LMP (20%). Researchers found a 10-day spread of observed ovulation days even among a group of people with "clockwork" cycles, and a similar variation for people whose cycles were a little longer or shorter.

Another group of researchers set out to pinpoint the most commonly fertile day in the menstrual cycle across the general population—including those with irregular cycles—using menstrual period surveys and ultrasound measurements rather than ovulation signs. They found a sharp rise in the probability a person will conceive beginning at day 7 LMP, reaching a maximum probability of conception of 13% at day 15 LMP. By day 25 LMP, the statistical probability of conception is zero, according to the data.

How Can You Know If You're Not Ovulating?

Some people do not ovulate regularly, or at all. One in 10 people with ovaries experience anovulation, or periods in which an egg is never released during their menstrual cycle, at some point during their childbearing years. If you're not ovulating, no amount of sex will get you pregnant.

Irregular periods or completely absent periods are the number one sign that ovulation may not be occurring, or may be occurring infrequently. It is possible to have regular periods and not be ovulating, but this is uncommon.

A Word From Verywell

Understanding the science behind fertility as it relates to the timing of ovulation is helpful if you are trying to have a baby. But it's important to know that not everyone's fertile window falls at the same time of the month. When trying to figure out the best time to conceive, it may be more helpful to watch your body's signs of fertility—like changes in cervical mucus—than the calendar.

Research has also found that timing sex for pregnancy can cause excessive stress in some couples. If trying to conceive is causing a strain on the relationship, you may decide to ditch the monitoring methods and just try to have sex as often as is enjoyable for both you and your partner.

If frequent unprotected sex doesn't get you pregnant after a year (or six months, if you're over 35), then you may choose to see a fertility expert for an evaluation. Of course, if you have any possible signs of a fertility problem (including signs that you may not be ovulating), you don't need to try to conceive for a year before you see your doctor. You can be proactive and make that appointment now, with both a future baby and your own reproductive health in mind.

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8 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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