Basal Body Temperature Charting

What is my BBT ?

Your basal body temperature (BBT for short ) is your resting body temperature ie your temperature when you are at rest.

When is the best time to measure my BBT ?

For most women the best time to measure the BBT is first thing in the morning when you wake, before you get out of bed, and before you do anything at all.

How do I measure my BBT ?

You will need to use a high accuracy clinical thermometer- the easiest to use is a digital thermometer that measures to 2 decimal places

Where do I put the thermometer to measure my BBT ?

For most women the best & simplest place to measure your BBT is under your tongue

How long do I leave the digital thermometer under my tongue ?

Most digital thermometers will beep when they have reached a stable temperature, making it quick and easy to know when to remove the thermometer. It usually takes around 1-2 minutes for this to happen.

What do I do with the basal body temperature results ?

You will need to chart the BBT results on a temperature chart , so that you will be able to see the pattern develop.

Here is an example of a BBT chart

Is there anything I should not do when doing my BBT ?

Moving around, eating, drinking, smoking & even talking will raise your temperature, so make sure you do the temperature immediately upon waking each morning. If possible measure it while you are still “half asleep”.

What else can raise my basal temperature apart from ovulation ?

Illness if associated with fever will alter your resting temperature making interpretation of results problematic.

How does BBT charting help me predict my fertile time ?

Charting your basal temperature is helpful in determining whether and when ovulation occurs. Ovulation is the release of an egg (ovum) from the ovary and usually happens only once in each menstrual cycle. Conception can take place only if intercourse takes place immedictaely before , during or immediately after you ovulate.

By carefully recording your basal temperature when you first awaken, you will begin to notice a pattern of temperature fluctuation in your monthly cycle. The slight increase in basal temperature is an indication of ovulation or fertility.

Do I need a special thermoeter for BBT charting ?

You may use any clinical thermometer, as long as it is high accuracy. As the temperature change you are looking for is very small, it is best to use a thermometer that shows very small fluctuations in temperature.

Many women find it simpler to use a high accuracy digital thermometer rather than a glass thermometer, as they are quick and simple to interpret, and they beep when they reach a steady temperature. Glass thermometers can also be fragile.

Click here to find out more about high accuracy digital thermometers suitable for BBT or to buy one

Click here to visit babycentre who have free BBT charts that you can download and print