Ovulation - How do I know when I'm ovulating?

Ovulation should happen in a healthy menstrual cycle and if you're trying to have a baby, it's a crucial part. In fast, ovulation issues is the most common problem for women struggling to conceive.

You can get pregnant if you have sex on about six days in each cycle - five days before ovulation (because sperm can "wait" for an egg in your fallopian tubes) and the day you ovulate. After ovulation the egg only survives around 24 hours.

Understanding your cycle and ovulation can therefore help you if you want to get pregnant, but also if you want to avoid it. For example, getting pregnant ten days before or four days after ovulation is completely impossible.

But how do you know when you ovulate then? If you have a regular menstrual cycle, you will most likely ovulate 11-15 days before your next period. Some women may feel a slight pain in the lower abdomen during ovulation, but most of us feel nothing and need other tools to identify it - we will go through some of the in this article.

Remember - all bodies are different and the best way to get to know your body's unique signals is to track them over several cycles.

Signs that ovulation HAS taken place:

Your period

Your period is usually sign that you've ovulated, especially if you have a regular cycle. With a functioning cycle ovulation issues are rare. Still, menstruating is not a 100% proof of ovulation because you could build up a uterine lining even through an egg was never released. If you have an irregular cycle, it could be a sign that something is not working as it should and it it is then particularly important to start tracking your ovulation to understand it better.

A temperature increase

Your body temperature is affected by various factors, including which phase of your menstrual cycle you're in. It's the hormonal changes that occur throughout the menstrual cycle that cause it to change.

After ovulation the ruptured egg follicle produces progesterone, and this hormone affects the heat generation in the body causing your body temperature to rise. If you become pregnant, the progesterone level and your temperature will remain elevated. If you don't get pregnant, the progesterone level will drop and so will your temperature. Your temperature is at its lowest when you're menstruating and the day before ovulation and then increases immediately after ovulation. To confirm that ovulation has taken place, the temperature rise must last for three days.

You measure what is called basal body temperature, which is the temperature you have when you are completely rested (after at least 5 hours of sleep) and you measure it in the morning before you've had time to get out of bed. You need to use a specific basal thermometer that shows two decimals as these changes are small (0.2-0.5C). And - this method requires that you measure temperature at least 5 days a week throughout the menstrual cycle to be able to follow the changes.

Rising progesterone levels

As we mentioned above, ovulation leaves a ruptured follicle that produces the hormone progesterone (and a bit of estrogen). Your ovaries are filled with these follicles that store your egg cells until ovulation releases them. If you hear about the "corpus luteum", this is another word for this ruptured follicle.

So basically - a high progesterone level is a proof that ovulation has taken place. It can give a clearer answer than measuring temperature (the effect of the rising progesterone levels), but it's more complicated to measure as a blood test has to be used. Some home tests which could make it easier have also started to appear on the market though,

It's important ot measure progesterone on the right day; 7 days after ovulation. Often, women are told to test on day 21 of the menstrual cycle, but this is based on that all women have a 28 days long cycle and ovulate on day 14 which isn't true for many of us. You need to track your cycle to understand when you ovulate.

Signs that ovulation IS ABOUT to happen

A rise in LH

LH stands for luteinizing hormone, which is secreted by the pituitary gland in the brain just before ovulation; about 24-48 hours before). The ovulation tests (urine tests) that are found in most pharmacies and grocery stores look for this change in LH.

When a test shows a peak in LH, you can assume ovulation will happen within 24-48 hours, but it's not a 100% proof it actually will happen.

Some ovulation tests will not only show the LH peak, the day of peak fertility, but also a few fertile days leading up to this. That's because these tests also measure estrogen which start to rise earlier than LH. And since your'e fertile a few days before ovulation too (read the intro above if you've forgotten why), these are considered fertile days as well.

Your mucus

Throughout your menstrual cycle, your cervical mucus changes appearance and texture. Again, due to the hormonal changes that happen in your body. So if you learn to interpret the changes, it can be a useful way to determine when ovulation is about to happen and when you're fertile.

It's really quite logical when you learn because different types of mucus are more or less "sperm friendly".

Just before your period and after your ovulation - when you're not supposed to become pregnant, your mucus is creamy (like body lotion) or thick and sticky. Makes sense it's difficult for sperm to get through this, right?

In contrast, as ovulation approaches, the rising estrogen levels makes mucus thinner and watery, which is called fertile mucus. And then, just before ovulation, you often get mucus that looks like a raw egg white and is elastic/stretchable; it creates strings between your fingers if you hold it up (you can google pictures on this if it sounds weird). This is the most sperm friendly and thus fertile mucus!

An ultrasound examination

Another way to understand if your ovulation is on its way is to monitor the development of your ovaries via ultrasound.

By doing a number of ultrasounds, one can identify that a follicle is growing Usualy sevreal to start with, and then one dominant) and , later, that it has collapsed. But this is of course complicated and time consuming, and is normally only done if you undergo a fertility investigation or treatment.


Evangelia Elenis, MD, PhD.

This text is fact checked by Evangelia Elenis, MD, PhD. Dr. Elenis is a chief physician in Obstetrics and Gynecology, and a subspecialist in Reproductive Medicine. She is a PhD and affiliated researcher at Uppsala University with postdoctoral studies at Harvard Medical School.

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