The temperature curve: ovulation and pregnancy

Ovulation: what is the temperature curve?

The temperature curve is a method of determining the day of ovulation , a posteriori . This involves taking your temperature every morning, when you wake up and before you have put the slightest toe on the ground, not even to pee, from the first day of your period.

If ovulation has occurred, the next day you should see a rise in temperature of a few tenths of a degree .

Why calculate your temperature curve to know if you are ovulating?

Concretely, the analysis of the temperature curve is most often used when trying to get pregnant . Ovulation indicated, a posteriori , by the increase in body temperature (also called Basal Body Temperature).

The body temperature of women and people with a vulva changes throughout the menstrual cycle. Usually the body temperature is below 37 degrees celsius .

Just before the period of ovulation, the temperature drops and then rises above 37°C during the luteal phase (after ovulation). In pregnancy, the basal body temperature remains above 37°C for at least 10 to 14 days, until the next period is due.

Why do we insist on the “ a posteriori ”?

Because the increase in temperature (by a few tenths of a degree) only occurs the day after ovulation : one cannot therefore anticipate perfectly precisely the moment of one's ovulation. However, once there has been ovulation and the egg has been released, it only has a very short lifespan (between 12 and 24 hours), unlike sperm.

In the follicular phase, estrogens are predominant, and have the effect of maintaining a rather low body temperature, generally below 37°C, while in the luteal phase it is progesterone which is predominant: it is this which causes the rise in temperature (between 0.3 and 0.5°C) which is maintained throughout the second part of the cycle, until the next period. Don't hesitate to read our article on the basics of the menstrual cycle , so you don't get lost;)

How to take your temperature and make your temperature curve?

Here are the steps to follow to create your temperature curve:

1) Take your basal temperature every morning before getting out of bed (the slightest movement can impact your temperature), preferably at the same time each day. Use a basal thermometer , which is more accurate for measuring small changes in body temperature. Prefer taking rectal or vaginal temperature (we know, it's not funny, but it's still more precise). Comment if you have taken any medications, drank alcohol or slept little, as this can also impact your temperature.

2) Record your temperature each day on a temperature curve chart . You can use a graph paper chart or an app like Clue that lets you record your daily temperatures and save you the school supply aisle of the Monop' to find graph paper.

3) After several days, you may notice a slight drop in temperature followed by a rapid rise . This temperature increase indicates that ovulation has occurred. In general, the temperature will increase by about 0.5 degrees Celsius.

4) Continue taking your temperature every day for several months to establish a more complete temperature chart. This will help you determine your average menstrual cycle and identify temperature patterns that may indicate fertility issues.

It is important to note that the temperature chart does not work for all people and can be influenced by many factors , such as sleep changes, infections, stress, travel, and medications. It is therefore important not to rely solely on this method to determine the time of ovulation, but rather to combine it with other methods of observing signs of fertility, such as observing cervical mucus.

Diagram of an example of a temperature curve

Make love before the expected date of ovulation rather than after the "temperature peak"?

Precisely because once you have noticed the rise in temperature, it is already almost too late to hope for fertilization, since the egg was released the day before and its "lifespan" is very short (between 12 and 24 hours).

On the other hand, by having a report a few days before the anticipated date of your ovulation, you can hope that there will be fertilization, for the simple and good reason that a spermatozoon has a much longer “lifespan” (a few hours to a few days for the most valiant).

So, if you want to maximize your chances of getting pregnant, prefer intercourse before and during ovulation and don't wait to see the temperature rise.

Also, we advise you to use a non-spermicidal lubricant which helps with conception as well as a conception cup which allows you to keep the sperm longer and to help the spermatozoa to pass the cervix.

Why don't you see a "spike" in temperature during your cycle?

If there is no detected temperature rise (despite all your rigor) and no ovulation; we speak of anovulation , that is to say the absence of ovulation.

Indeed during certain cycles, it can sometimes happen that an egg is not released. This phenomenon, called anovulation, often affects young girls who have just started menstruating, or women who are approaching menopause, but it also happens that healthy women do not ovulate.

If you are looking to have a child and you notice several anovulatory cycles, it may be important to consult your specialist.

Can the temperature curve be used as a means of contraception?

No, by practicing this method in a perfectly rigorous way, you will obtain at best a super fine knowledge of your cycles, but in no case a reliable means of contraception . To do this, use condoms or other effective contraception.

In conclusion, the temperature curve, even if it requires a lot of rigor (and almost the lifestyle of a Trappist monk, let's be honest), can allow you:

• better understand your menstrual cycle and detect potential ovulation problems
• to identify a posteriori the day of your ovulation (or the absence of ovulation)
• over time and if your cycles are regular: to anticipate the most fertile phases to conceive a child (or precisely to avoid conceiving one!)