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Body Basal Temperature (BBT) Charting

Everything You've Ever Wanted to Know About BBT Charting

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Updated July 11, 2014

BBT (basal body temperature) charting is a popular way to detect and track ovulation. You may use a BBT chart to help determine when you are ovulating, so you can time sex for pregnancy. Or, you may share your BBT charts with your doctor to help diagnosis potential causes of infertility, like irregular ovulation.

Before You Buy a BBT Thermometer

Close up of man holding thermometer
Sigrid Gombert/Collection Mix: Subjects/Getty Images
If you’re planning on charting your BBT, you'll need a thermometer. There are thermometers made especially for tracking your body basal temperature, but you might not need one. A thermometer you have at home may be good enough. Learn what you should look for in a BBT thermometer.

How to Take Your BBT

Maybe you’ve got a BBT thermometer already, and now you’re ready to take your temperature. If you’re trying to detect ovulation, you can’t take your temperature just any old way. For example, you must take it first thing in the morning, before you’ve gotten out of bed. (You can’t even get up to go get your thermometer!) Learn what you need to know about taking your BBT properly in this how-to piece.

How to Chart Your BBT

Basal Body Temperature Chart with Ovulation / iStockPhoto
Photo © iStockPhoto
Your individual body basal temperature 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? Where can you get charts online for free? Learn what you need to know about charting your BBT in this step-by-step tutorial.

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

Positive pregnancy test
Photo: Don Farrall / Getty Images
Many women will pour over their BBT chart, looking for hints or clues to pregnancy. The two-week wait is pure torture, and it would be wonderful if we could find a way to predict pregnancy earlier, before our period is late. Can your BBT chart provide hints to an early pregnancy? Maybe yes, but mostly no. Learn how your BBT chart can, and can’t, help detect pregnancy.

Implantation Dips

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?

Triphasic Charts

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.

How to Check Cervical Mucus

While your basal body temperature can tell if you’ve already ovulated, it can’t tell you when ovulation is approaching. And 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.

How to Check Cervical Position

Picture of Uterus and Cervix
Photo © A.D.A.M.
Yet another way to detect ovulation is by tracking your cervical position. 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. It’s also helpful to track your cervical position if your cervical mucus is absent, because of anti-histamines. Learn how to check your cervical position, and how to detect approaching ovulation.

7 Signs of Ovulation

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. For example, sensitive breasts probably indicate that ovulation has already occurred. Learn about more signs of ovulation, which you can track on your BBT chart.
  1. About.com
  2. Health
  3. Fertility
  4. Ovulation, Sex for Pregnancy, and Reproduction Basics
  5. All About Ovulation Signs and Detecting Ovulation
  6. Body Basal Temperature (BBT) Charting (Ovulation)

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