Basal temperature

Basal Body Temperature (BBT) is the lowest body temperature attained during rest, usually during sleep. It is generally measured immediately after awakening and before any physical activity has been undertaken. This temperature can be influenced by various factors such as menstrual cycle, illness, and lack of sleep.

Overview

Basal body temperature is a person's body temperature taken immediately after waking up in the morning, or after at least three hours of uninterrupted sleep. It is usually measured with a specially designed thermometer known as a basal thermometer.

Use in Fertility Awareness

Basal body temperature tracking is often used in fertility awareness methods for predicting ovulation. A slight rise in BBT, typically by 0.5 to 1.0 degrees Fahrenheit, can indicate the onset of ovulation. This method is often used by women trying to conceive or avoid pregnancy.

Factors Affecting Basal Body Temperature

Various factors can affect the accuracy of BBT readings. These include illness, lack of sleep, alcohol consumption, and certain medications. It is important to take these factors into account when interpreting BBT charts.

Measurement and Charting

BBT is typically measured first thing in the morning before any activity is undertaken. The temperature readings are then charted over time to identify patterns and predict ovulation.

Limitations

While BBT tracking can be a useful tool in fertility awareness, it is not foolproof. It can only predict ovulation after it has occurred, not before. Therefore, it should not be used as the sole method of contraception.