Ovulation

Ovulation is an important part of the menstrual cycle and it plays a major role in pregnancy. Most women ovulate once a month. During ovulation an egg is released from your ovary. If this egg gets fertilized by sperm it may implant in your uterus and grow into a baby. If the egg is not fertilized, you’ll go on to have your monthly period. This cycle repeats until menopause. Understanding how ovulation works—and when it happens—can help you achieve or prevent pregnancy.

What is ovulation?

Ovulation is when one or more eggs are released from one of your ovaries. This happens toward the end of the time you’re fertile between periods.

Getting to know when you’re ovulating is one of the best ways you have of gaining control over your fertility. We share the secrets of how ovulation works, and how you can learn to recognize your fertile periods by reading the clues your body gives you.

Each month, between 15 and 20 eggs mature inside your ovaries. The ripest egg is released and swept into one of your fallopian tubes, which connect your ovaries to your uterus (womb) (Cleveland Clinic 2022c).

Your ovaries do not take turns releasing an egg. It happens from either side, at random.

How does ovulation affect when I can get pregnant?

To become pregnant naturally one of your eggs and the sperm have to meet in your fallopian tube. Your egg survives for up to 24 hours after you’ve ovulated (SOGC nd). So, the meeting of egg and sperm has to occur within this time.

Sperm can survive for up to 7 days in your vagina, uterus, or fallopian tubes. This means that you don’t have to time sex, or assisted conception by a sperm donor, to happen at the exact moment you ovulate in order to get pregnant. You have a fertile window of about 6 days.

This window includes a few days before and the day of ovulation itself (SOGC nd). So, if you attempt to get pregnant at some time during your fertile window, your freshly ovulated egg could meet live, healthy sperm and be fertilized.

When is ovulation?

The simplest way to work out your most fertile time is to note down the length of your menstrual cycle. Then look out for changes in your body.

You’ll start to notice signs that you’re fertile about five days before you ovulate. Ovulation usually occurs between 12 and 14 days before your period starts (SOGC nd). This is an average, so it could be a couple of days earlier or later than that.

So, say you have a regular 28-day menstrual cycle. Count the first day of your period as day one. Your fertile window is likely to be around days 13 to 15 (SOGC nd).

A lot of people have an irregular cycle. In that case ovulation may occur a week earlier or later from one month to the next.

How can I tell when I’m most fertile?

Working out your fertile window using your cycle dates alone is not always exact. This is why learning to spot your body’s fertile signs can help. These include:

Changes in cervical mucus

Cervical mucus is the discharge that you see in your underwear or on toilet paper after going to the washroom.

Changes in your cervical mucus can signal when you are fertile (SOGC nd). After your period has finished, your cervical mucus starts to increase in amount, and it changes in texture.

This change reflects the rising levels of the hormone estrogen in your body. It also shows you are close to ovulating (Campbell and Rockett 2006).

You are most fertile when your mucus becomes clear and stretchy. It will look a bit like raw egg white. This fertile mucus speeds the sperm on its way up through your uterus (Cleveland Clinic 2020a). It feeds and protects the sperm, as it travels toward your fallopian tubes to meet your egg.

See our photo gallery to get to know what cervical mucus looks like.

An ache in your belly

About 1 in 5 people can feel it when they ovulate. This can range from mild aches, to twinges of pain (NHS 2019). Some people feel ovulation as one-sided backache or a tender area. The condition, called mittelschmerz, can last from a few minutes to a few days.

If you notice this at roughly the same time each month, check your cervical mucus. Ovulatory pain can be a useful sign that you’re fertile.

Feeling sexy

Feeling sexy, flirty and more social may all be signs that you’re at your most fertile. You may notice a peak in sexual desire at this time, too (Cantú SM et al 2014).

Think back over your last cycle. You might recall looking and feeling great at a certain point. You’re likely to feel more attractive as you near ovulation (Cantú SM et al 2014).

You also smell good to others at this time. Your body odour is more pleasant around the time you’re fertile (Tarumi W, Shinohara K 2020).

Try our ovulation calculator to help you work out when your fertile window is likely to be.

How can I increase my chances of getting pregnant, if I’m trying to conceive naturally?

Try to have sex every two to three days. This way, sperm should be in the right place when you ovulate. Sex often, throughout your cycle, gives you the best chance of conceiving (Mayo Clinic 2021).

Lots of women use ovulation test kits to pinpoint their most fertile time. Most of these kits test for the peak of the luteinising hormone, or LH surge, which is the trigger for egg release. You could use one to find out when you're most fertile during your menstrual cycle, although using them to time sex won’t always increase your chances of getting pregnant.

Making love when your cervical mucus is wet, slippery, and most receptive to sperm will also increase your chances of conception.

And you’ll be happy to know that the odds are with you.

In normally fertile couples, there is a higher than 25 per cent chance of getting pregnant each cycle (Cleveland Clinic 2022b).

Most couples who have sex often, and without using contraceptives, will get pregnant within a year from the point that they start trying (NHS 2020). Nearly all couples conceive within two years.

Find out about the best sexual positions for baby-making.