The basal body temperature method is a technique used in family planning. Basal temperature is the temperature of your body when you are completely at rest.
After a woman ovulates (releases an egg from the ovary), her body temperature rises slightly. While tracking the basal body temperature during multiple menstrual cycles cannot actually predict when you are going to ovulate, it can help to establish a pattern. You will then be able to understand when you are likely to ovulate.
Detecting ovulation can help you identify the days you are most likely to become pregnant. With this information, you can tell the best days to have sex if you want to become pregnant. It also helps you know which days you should avoid sex or use another birth control method to avoid becoming pregnant.
People use this method to determine a woman’s most fertile days of the month. Some women who want to get pregnant measure basal body temperature to identify the best days of the month to have sex. Women trying to avoid pregnancy may use it to know which days they should avoid having sex.
Some women choose the basal body temperature method because they do not want to take medications or hormones for birth control. In some cases, people use the method for religious reasons.
In any case, it might take a while to get used to tracking and recording temperatures and to being aware of the changes in your body. Other signs that indicate where you are in your cycle include breast tenderness, pains near an ovary, and the state of your cervical mucus. Many women keep track of the day that their periods start and when they end.
To use the basal body temperature method:
The basal body temperature method has no side effects. The only cost is the price of the thermometer.
The basal body temperature method may not accurately predict ovulation in all women, including those with irregular menstrual cycles. It offers no protection from sexually transmitted diseases.
Sometimes this method is not effective in preventing pregnancy due to outside factors that can affect basal body temperature. Factors that can alter this temperature include:
Ask your doctor if the basal body temperature method may work for you. Many family planning experts recommend combining the basal body temperature method with other methods of natural family planning such as the cervical mucus method.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 04/23/2019