Everything You Should Know About Basal Body Temperature Charting

From Detecting Ovulation & Early Pregnancy to Watching for Other Fertility Signs

Basal body temperature charting is a popular method of ovulation detection, and many women trying to get pregnant try it out. There are so many advantages of charting your basal body temperature (or BBT, for short.)

Charting can help you:

What is your basal body temperature? How can you get started with charting? Can you tell if you're pregnant from looking at your chart? What else should you be charting, besides your temp?

All the answers are below! 

The Best Way to Take Your Basal Body Temperature

Woman in bed stretching before she takes your body basal temperature for her chart
To get an accurate reading, it's important you don't move around a lot before you take your basal body temperature.. Quiet Noise Creative / Getty Images

First of all, what is your basal body temperature? It is your body's temperature at complete rest. This temperature changes based on a number of factors, including your hormones. When you ovulate, the hormone progesterone causes your temp to rise. 

To know what your basal temp is, you must take your temperature in the morning before you get out of bed or move around. It's essential that you take your temperature properly. Otherwise, you may not be able to detect ovulation. 

Get many more details on your basal body temperature and -- most importantly -- how to take your BBT the right way for charting. More »

How to Chart Your BBT and Detect Ovulation

Photograph of a basal body temperature chart, with a woman pointing to ovulation day
You're not looking for one day's temperature but a pattern over many days.. Photo © iStockPhoto

An individual body basal temperature taken on a single day won’t tell you much. You can’t tell if you’ve ovulated or not unless you look at the pattern of temperatures over a period of days and weeks.

How can you detect ovulation on a BBT chart? Learn what you need to know about charting your BBT in this step-by-step tutorial. More »

Before You Buy a BBT Thermometer

Close up a woman holding a thermometer
They make special basal body thermometers, but you may not need one.. Sigrid Gombert/Collection Mix: Subjects/Getty Images

Obviously, you need a thermometer if you plan on charting! 

But does it matter which one you buy?

There are thermometers made especially for tracking your body basal temperature, but you might not need one. A thermometer you already have at home may be good enough.

Learn what you should look for in a BBT thermometer. More »

Can You Tell if You're Pregnant from a BBT Chart?

Woman looking intently at her basal body chart on her laptop
You can spend hours obsessing over your chart... try not to.. Robert Warren / Getty Images

If you are a dedicated BBT charter, and you're not scouring the data looking for ovulation and pregnancy clues, you are a rare woman.

At the start of the month, you spend days looking for ovulation... and then -- once you've unlocked that achievement! -- you start looking for early pregnancy clues. Are they in there to be found?

Maybe yes.  

Learn how your BBT chart can, and can’t, help detect early pregnancy. More »

Are Implantation Dips a Myth?

Basal body temperature chart with ovulation and implantation dip showing
On this basal body chart, ovulation occurred on Day 15 and the implantation dip was on Day 23 (which is eight days after ovulation.). Rachel Gurevich

One BBT chart pattern that some say indicates pregnancy is an implantation dip.

It’s called an implantation dip because, according to the theory, your temperature will dip slightly when the embryo is implanting into the uterine wall.

Are implantation dips real? How do you know if you had one? Is it a reliable sign of early pregnancy?  More »

What Is a Triphasic Chart? Does It Mean Anything?

BBT (Basal body temperature) chart with triphasic shift illustrated
In this chart, the first temperature shift indicated ovulation on Day 15. Then, there is another temperature shift 10 days past ovulation. This is a triphasic pattern.. Rachel Gurevich

Another envied BBT chart pattern is the triphasic chart pattern.

All BBT charts that detect ovulation are biphasic, meaning that there are two distinct levels of temperatures. The temperatures before ovulation are generally lower than the temperatures after ovulation.

With a triphasic chart, there is a third sustained rise in temperature, about a week after ovulation has been detected.

Could a triphasic chart be a positive sign towards pregnancy? Maybe. More »

Why You Should Also Be Charting Your Cervical Mucus

Woman coming out of the shower, where it's easy to check for fertile cervical mucus
If you get into the habit of checking your cervical mucus when you shower, it can be easy to add this info to your BBT chart.. Ghislain & Marie David de Lossy / Getty Images

While your basal body temperature chart can show if you’ve already ovulated, it can’t tell you when ovulation is approaching. If you want to get pregnant, you need to have sex before ovulation -- not after.

One way to make BBT charting more helpful is to also track the changes in your cervical mucus.

Some studies actually show that tracking cervical mucus is a far more reliable way to time sex for pregnancy than BBT charting alone.

Find out how to check your cervical mucus here, and how to chart what you find here. More »

When You Have Fertile Cervical Mucus But Don't See a Temp Rise...

Woman looking at her BBT chart on her phone, confused
There are a number of possible reasons you can see fertile cervical mucus but not see a temp rise.. PhotoAlto/Eric Audras / Getty Images

So, if all goes well, you should see fertile quality cervical mucus just before your basal body temperature rises. Egg white cervical mucus should indicate ovulation is just around the corner.

But what if you get cervical mucus, but don't see a temperature rise after? There are a few possible reasons why... More »

Charting Your Cervical Position to Detect Ovulation

Illustrations of cervical opening in woman who has given birth and who has never given birth
Your cervix changes based on where you are in your cycle.. Morphart Creation / Shutterstock

Your cervix is pretty amazing. Another way to detect ovulation is by tracking how your cervix changes before ovulation.

And, yes, you can add this information to your chart.

It’s not as common for women to track their cervical position, but it’s additional information that you can use to time sex for pregnancy.

If you're taking anti-histamines (which dries up fertile cervical mucus), then tracking your cervical position can be especially helpful.

Learn how to check your cervical position and detect approaching ovulation. More »

The Top 4 Free Fertility Charting Websites

Graph paper, pens, and glasses, ready to be turned into a BBT chart
Sure, you could track your BBT on graph paper by hand... but why?!. PhotoAlto/Odilon Dimier / Getty Images

Where are you going to write all these charting details down? 

There are dozens of free fertility charting websites and apps available. You don't need to get out your colored pencils and graph paper and do this on your own. (Though, I mean you could, if you wanted to...)

Here are the very best of the free fertility charting websitesMore »

7 Signs of Ovulation

Couple in bed about to have sex to get pregnant
Nature is smart. When you're most fertile, you and your partner feel more interested in having sex.. Jamie Grill / The Image Bank / Getty Images

Depending on how detailed of a BBT chart you want to keep, you can write down all kinds of symptoms and signs that indicate ovulation. 

Other possible ovulation signs include:

Learn more about these ovulation signs here! More »

How Can You Know if You're Ovulating?

Woman sharing her basal body temperature chart to her doctor
If you're not ovulating, see your doctor. Bring your BBT charts with you!. Hero Images / Getty Images

One of the advantages of charting is you can see whether you are ovulating.

If you're not ovulating, you can't get pregnant. If you are ovulating irregularly, it may indicate a possible infertility risk.  

What are some other ways to know if you're ovulating? And what should you do if you're not? More »

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