If you are just getting started with bbt charting or if you would like to start charting, the first thing you will need is a basal body thermometer. There are several on the market. If you can’t find one at your pharmacy, you can purchase a basal body thermometer online. A fever thermometer is not as sensitive as a basal thermometer and is not advised for bbt charting. A lot of women use thermometers that read temperatures to the 1/100th degree, this is not necessary and may make your chart more confusing to read. A digital basal thermometer that reads to the 1/10th degree is great for charting. Look for one that keeps a memory so that you don’t have to write your temperature down right away.
Take your temperature right when you wake up.
It is important that you take your temperature as soon as you wake up. Do not get up out of bed until you take your temperature. The easiest way to do this is to keep your thermometer at your bedside. The reason behind taking a waking basal temperature is that your temperature shifts throughout the day depending on what activities you are doing. Activities like getting up and going to the bathroom could cause your temperature to go up and make your chart inaccurate.
Taking Temperatures Orally or Vaginally
You can take your temperature orally or vaginally. Some women find taking their temperatures vaginally is more accurate, but it’s really up to you. Once you decide which method you will temp with, stick with it throughout your fertility cycle. If you start with oral temps and then switch to vaginal, your chart will not be accurate.
Try to be consistent with taking your waking temperature.
You will have a more accurate chart if you take your temperature at the same time every day. If you over sleep, Take your temperature and make a note of it on your chart.
Make sure you have at least three hours of sleep.
If you have not had enough sleep when you take your waking temperature, your results may be inaccurate.
Occasionally you may have a temperature that is unusually high and seems out of place. For example, you may have a high temperature that doesn’t mesh with the rest of your chart. Fevers, stress, alcohol, and other factors may contribute to high temperatures. You may want to disregard this temperature when interpreting your chart.