What is a basal thermometer and why do I need one? Won my normal fever thermometer work?
The term “basal” means “at rest” and “basal body temperature” refers to your body temperature at rest. Natural Family Planning users typically take their temperature at the same time upon rising in the morning — before they have eaten, exerted themselves etc. NFP techniques evaluate changes in basal temperature to determine when ovulation has taken place. Fever thermometers are not accurate enough to be used with NFP, as a change of as little as 1/10th of a degree Fahrenheit (1/20th of a degree Celsius) can have an impact upon fertility prediction. Different types of basal thermometers are available, including both the mercury type and the new digital variety. We recommend the digital basal thermometer, due to its ability to read your temperature in less than a minute.
