How Do You Know When You Are Ovulating?

Want to know when you are ovulating? It starts with understanding your menstrual cycle. This is the monthly series of changes that a woman’s body goes through to prepare for the possibility of getting pregnant. The release of an oocyte from the ovary is an essential part of this process.

The luteal phase is the second half of your cycle. It starts after ovulation and ends with the first day of your period. Learn more about the phases of your cycle here.

The 101: What Is Ovulation?

Ovulation occurs during your reproductive years—basically from when your period (menarche) begins to when it ends (menopause). It’s defined by an event, on approximately day 13 to 15 of a 28-day cycle, during which your ovary releases an oocyte from a follicle. The oocyte then travels to the fallopian tube and awaits fertilization with sperm.

The rupture of the ovary follicles can cause some light spotting and some can even feel it happen in their body. However, for the vast majority, the moment when women ovulate usually goes unnoticed.

The process of ovulation is controlled by the hypothalamus of the brain and through the release of hormones. This means that ovulation can be impacted by hormone levels and stressors. From jet lag to thyroid disorders, the sensitive process of ovulation can be disrupted when your body undergoes changes. Hormonal contraceptives inhibit ovulation to prevent pregnancy. 

After the oocyte is released from the ovary, it moves into the fallopian tube. At this point it is called an ovum or egg. The egg stays in the fallopian tube for about 24 hours, waiting for a single sperm to fertilize it.

If the egg is not fertilized by sperm during that time (and pregnancy does not occur), it disintegrates (breaks down) and menstruation (your menstrual period) begins 11–16 days later.

Ovulation and Pregnancy: The Fertile Window

For many, ovulating is an unnoticed process. However, for those hoping to get pregnant, knowing when you might be ovulating is important.

Your most fertile days (the “fertile window") are the 3 days leading up to and including ovulation. This is when you’re most likely to get pregnant. So, having sex then gives you the best chance of ensuring the egg is fertilized by sperm so you become pregnant.

But, as previously mentioned, ovulation is a delicate process. Not to mention, the woman's reproductive cycle is just one side of the equation. Sperm heath is also key in your chances of getting pregnant.

As many will attest, your cycle can be impacted by stress, exhaustion, or emotional events (like grief). Moreover, nutrition, smoking, and seasonal changes can also impact ovulation and therefore fertility.

This is one of the reasons birth control doesn’t just focus on ovulation. When the realities of life kick in, the fertile window can be a bit of a moving target. As we all know, our bodies don’t always follow the rules ;)

How Do You Know When Ovulation Occurs?

Ovulation and your fertile window is a single phase in the ovarian part of your menstrual cycle, so understanding the phases and length of your cycle is key.

The most commonly referenced cycle length is 28 days (even though it is not the average cycle length, as most women will have slightly longer or shorter cycles). There are 3 phases that your ovary goes through to prepare for the possibility of fertilization and pregnancy, ovulation being one of them. (Again, please keep in mind the time frames below are averages and most women will experience time frames longer or shorter than average).

1. Menstruation (a phase of the uterus that occurs during the follicular phase of the ovary): More popularly referred to as your period, menstruation (or menses) marks the first day of your cycle. If an egg has not been fertilized, your uterus sheds its lining from the previous month’s cycle. This is your period.
2. Follicular phase: The follicular phase of your cycle starts on the first day of your period (day 1 of your cycle) and ends with ovulation (approximately day 13–15 of a cycle of 28 days).
3. Ovulation: This phase occurs after the follicular phase ends around days 13–15 of your cycle, in a 28-day cycle. The day of ovulation is distinctly defined by the act of the oocyte bursting through the ovarian capsule, out of the ovarian follicle, traveling through the fallopian tube, and becoming available for fertilization by sperm. The 3 days leading up to and including ovulation is when the baby-making magic happens.
4. Luteal phase: This phase lasts approximately 2 weeks after ovulation (day 17–28 in a 28-day cycle). During this phase, the egg begins to break down and disintegrate. If an egg isn’t fertilized before it starts to break down, it will shed with the next menses, and the cycle begins again.

When Does Ovulation Happen in the Menstrual Cycle?

As mentioned, every woman’s cycle is different. Some of us have longer periods than others, for example. So the timing of ovulation is not always the same in every woman's cycle.

A cycle can range between 21 to 35 days in adults and from 21 to 45 days in young teenagers. That's why most people track their own cycle with a period calculator or diary.

The first day of a cycle is counted from the first day of your menstrual period. You ovulate about 14 days before your period starts.

So, if your average cycle is 28 days and the first day of your cycle is day 1 of your menstrual period, day 14 in your cycle is your day of ovulation, and your most fertile days are days 12, 13, and 14. These are the days pregnancy is most likely to occur.

Or, if your average cycle is 35 days, ovulation happens around day 21 and your most fertile days are days 19, 20, and 21.

Ovulation Symptoms

Ovulation signs usually go unnoticed, but there are some ovulation symptoms that most women can learn to track or pay attention to. Ovulation symptoms include your basal body temperature, cervical mucus, and more...

Your Basal Body Temperature Falls

One of the most objective ovulation symptoms is that your basal body temperature drops a little bit just before the oocyte is released from your ovary. Then, 24 hours after the oocyte is released, your basal body temperature rises and stays up for several days. If you're trying to get pregnant, it's advisable to take your basal body temperature to understand when you're ovulating.

According to Healthlink BC:

• 36.1°C (97°F) to 36.4°C (97.5°F) BEFORE ovulation and
• 36.4°C (97.6°F)  to 37°C (98.6°F) AFTER ovulation 

If you're trying to get pregnant, take your temperature daily and keep track of your body temperature in a journal or app.

Cervical Mucus Changes When You Ovulate 

The changes in your cervical mucus over the course of your menstrual cycle also hold clues about when you might be ovulating.

If your cervical mucus is...

• Dry or sticky: It’s unlikely you’re ovulating
• Creamy cervical mucus: Ovulation may be coming
• Wet or watery: Ovulation may start soon
• Wet and stretchy (egg white texture): You may be at your day of ovulation 

It’s worth noting that cervical mucus is just one component of vaginal discharge, which can also include vaginal lubrication, arousal fluid, and more.

Again, making such observations is not an exact science and no woman is an exact clock. But if you keep a period diary and ovulation calendar, it might be worthwhile to also note any observable changes in cervical mucus. Over time, you may see a pattern emerge.

Your Cervix Softens and Opens Up

Ovulation symptoms include a softening of the cervix as you approach your most fertile time. This is sometimes known as having a short, high, open, and wet cervix (SHOW). 

For a step-by-step guide to checking your cervix position, visit this guide on Flo’s website. 

You May Experience a Slight Twinge or Cramping

Mittelschmerz translates literally as “middle pain” and is the name for the slight twinge or cramp that some women experience when the follicle releases the oocyte on the day of ovulation during their menstrual cycle.

For many women, there is no sensation whatsoever. So, it isn't as obvious as some of the other ovulation symptoms.

The pain will occur on 1 side of your lower abdomen. Because you have ovaries on 2 sides, the ovulation pain will switch sides each month, distinguishing it from the uterine cramping associated with menstruation.

According to the Mayo Clinic, “Mittelschmerz pain occurs on the side of the ovary that's releasing an egg (ovulating). The pain may switch sides every other month, or you may feel pain on the same side for several months. Keep track of your menstrual cycle for several months and note when you feel lower abdominal pain. If it occurs mid-cycle and goes away without treatment, it's most likely mittelschmerz.”

If the pain is more severe, you should seek medical advice from a healthcare professional.

Some Light Spotting May Occur When You Ovulate

When the ovaries release the oocyte, a tiny follicle ruptures to allow it to be released. This can be a cause of spotting for a day or so.

For some women, spotting that occurs around the time of ovulation is light red or pink in color. This is because we also produce more cervical fluid around the time of ovulation and the blood gets mixed with that fluid, causing it to be a lighter shade.

Increased Libido or Sex Drive

The most well-known sign of ovulation is an increased sex drive. This is thought to be an evolutionary reaction to increase the likelihood of pregnancy. It’s important to know that this does not mean you’ll only want to have sex during ovulation. But it may definitely mean that you may experience an increased libido when ovulation occurs.

According to a report on Psychology Today, "ovulating women do clearly increase their sexual desire, and they do increase the frequency with which they have sex with their current partners.”

How Long Do You Ovulate For?

Ovulation, or the fertile window, lasts between 12 and 24 hours. That's how long the egg released by the ovary is viable for fertilization.

What Interrupts Ovulation?

Ovulation may not happen for a variety of reasons—some natural and some not. It might depend on what phase you’re at in your cycle or there could be an underlying medical issue like polycystic ovary syndrome (PCOS), other endocrinopathies like thyroid disease, or elevated prolactin levels, nutritional deficiencies, or perimenopause.

If you’ve been trying unsuccessfully to get pregnant for over a year (under the age of 35, or over 6 months over the age of 35) you could potentially be dealing with infertility issues. If this is the case, you are not alone and there are a variety of treatments available to help. According to the Mayo Clinic, an estimated 10–18% of couples have trouble getting pregnant or having a successful delivery. 

Other major factors that affect ovulation include:

• Age: After age 35, a woman's odds of becoming pregnant decreases rapidly. 
• Smoking: Smoking accelerates ovarian follicle (where the oocytes are) depletion, encouraging loss of reproductive function. Menopause occurs 1–4 years earlier in smokers compared to non-smokers.
• Weight: Obesity (as per guidelines in which abdominal fat and waist circumference are the main contributors to excess) is associated with dysfunctional ovulation.
• Sexually transmitted infections (STIs): Sexually transmitted infections can damage the fallopian tubes making future pregnancies more difficult because the sperm is unable to get to the released egg.

How to Know Your Fertile Window: Ovulation Test Kits

In addition to tracking the signs of ovulation and common ovulation symptoms listed above, there’s another step you can take to predict ovulation. Using a tool to calculate ovulation is especially helpful for those struggling with getting pregnant, who need to identify the fertile window.

An ovulation predictor kit (also sometimes called an OPK, which stands for ovulation predictor kit) is a test that detects the presence and concentration of luteinizing hormone (LH) in your urine. Between 12–48 hours on average before ovulation, there is a brief surge in luteinizing hormone levels.

Ovulation predictor kits may be especially helpful for women trying to get pregnant or increase their fertility awareness, but also who have irregular cycles and irregular ovulation. However, the body can find ways to fool such ovulation tracking methods...

According to the American Pregnancy Association, “When taken correctly, ovulation predictor kits are approximately 99% accurate in detecting the LH surge that precedes ovulation. However, these tests cannot confirm whether ovulation actually occurs a day or two later. Some women may have a surge in the LH hormone without releasing an egg. This condition is known as luteinized unruptured follicle syndrome (LUFS).”

Your Ovulation Calculator

Tracking ovulation, learning the ovulation signs, and understanding when you ovulate (and even being able to feel ovulation happening) means you can predict when you’re likely to be fertile. More generally, it helps you become more familiar with your own body. This can help you appreciate the wondrous complexity of your body, but also notice any changes that might need medical attention.

Note: Online calculators give approximate ovulation dates and fertile times for women who have regular periods. These tools assume regular menstrual cycles, so if—like many women—you have irregular periods, they may not be reliable in helping you to pinpoint the day on which you ovulate.

If you're hoping to get pregnant, it's also important to talk to your healthcare provider about your overall health. Ideally, bring your partner with you. You may both have questions about the process and family planning impacts you both.

Some of the things you should discuss:

• Stopping birth control: If you've been on birth control, you should discuss how to stop taking it
• Supplements and lifestyle changes: Your doctor may advise you to take some supplements, like folic acid, before you get pregnant
• Current medications: If you're on any other medications, you'll want to discuss them with your doctor in light of a possible pregnancy
• Fertility questions: If there are suspected fertility problems, a male partner will also need fertility testing

Don't be shy about asking questions. Good luck!

Written by Jane Flanagan — Updated on April 5, 2022.

We hope you found this post informative — but remember: we’re not doctors and this post is not medical advice! While all posts are fact-checked and well researched, we always recommend you chat with your doctor about any questions or concerns you might have regarding a medical condition. We’re here to support and educate, but never with the aim of disregarding professional medical advice you’ve been given. Phew, now that that’s out of the way, you can go on living unapologetically free.