What happens to basal body temperature during ovulation

Topic Overview

The basal body temperature (BBT) is a person's at-rest temperature. Women can track their BBT to find out when they are ovulating. With this time line, a woman can learn when she is most and least likely to become pregnant.

When are you most likely to become pregnant?

About 2 weeks before your period you will ovulate, which means that one of your ovaries has released an egg. You are most likely to get pregnant on the day of ovulation and the 5 days before it.

When are you least likely to become pregnant?

Your egg is fertile for about 12 to 24 hours after you ovulate. Avoiding sex until several days after ovulation may help you prevent pregnancy. Keep in mind that your cycle can change, making it hard to know when you are ovulating. Some women use this information as a form of birth control. But it isn't very reliable for preventing pregnancy.

How can you predict when you will ovulate?

Your body temperature dips a bit just before your ovary releases an egg. Then, 24 hours after the egg's release, your temperature rises and stays up for several days. Before ovulation, a woman's BBT averages between 97°F (36.1°C) and 97.5°F (36.4°C). After ovulation, it rises to 97.6°F (36.4°C) to 98.6°F (37°C).

You can track your cycle by taking your BBT every morning. Take your temperature at the same time every day before getting out of bed. Next, record the results on a chart. If you have a somewhat regular cycle, the chart will help you predict when you will ovulate next.

What tools do you need to take your basal body temperature?

The change in your body temperature is very slight, so you need to use a special thermometer. You can use a regular digital thermometer or buy a basal thermometer. A basal thermometer shows you the temperature in tenths of a degree. This allows you to note tiny changes in body heat. This thermometer is faster and more exact than a regular thermometer.

Use a simple Fahrenheit temperature chart or Celsius temperature chart to track your temperature for several months.

Where can you get a basal thermometer?

You can find a basal thermometer or digital thermometer in a pharmacy or in the pharmacy section in many grocery stores. You can also find kits that include materials for measuring and charting BBT. These items are low in cost.

Credits

Current as of: February 23, 2022

Author: Healthwise Staff
Medical Review:
Kathleen Romito MD - Family Medicine
Adam Husney MD - Family Medicine
Femi Olatunbosun MB, FRCSC - Obstetrics and Gynecology

The basal body temperature method is a method of natural family planning that requires only the purchase of a very accurate thermometer. The method, which calls for tracking the woman's body temperature on a daily basis, helps to determine which days of the month she is fertile.

  • Overview
  • Procedure Details
  • Risks / Benefits
  • When to Call the Doctor
Basal Body Temperature
  • Overview
  • Procedure Details
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Overview

What is the basal body temperature method?

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.

Why is the basal body temperature method used?

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.

Procedure Details

How does the basal body temperature method work?

To use the basal body temperature method:

  • Make sure you have a thermometer that measures temperatures to at least one-tenth of a degree. This could be a regular digital thermometer or a special basal body temperature thermometer.
  • Take your basal temperature at the same time every day. The best time to take this temperature is immediately after waking up. Your body usually reaches its basal temperature when you are asleep..
  • Measure the temperature from the same place every day. The basal body temperature can be taken in the mouth, vagina, or rectum.
  • Record the temperature each day. Use a graph, list, or fertility-tracking app that allows you to compare each day’s temperature.
  • Identify a temperature increase. Basal body temperature typically rises less than ½ of a degree Fahrenheit after ovulation. It may take a few cycles to determine when this rise occurs each month.
  • Consider the fertile period. You are most likely to get pregnant during the period spanning 2 days before and 3 days after ovulation. If you are hoping to become pregnant, have sex during this time. If you want to avoid pregnancy, do not have unprotected sex until the fourth day after ovulation.

Risks / Benefits

What are the benefits of the basal body temperature method?

The basal body temperature method has no side effects. The only cost is the price of the thermometer.

What are the drawbacks of the basal body temperature method?

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:

  • Breastfeeding
  • Drinking alcohol
  • Fever caused by illness or infection
  • Oversleeping
  • Stress
  • Taking some medications
  • Traveling to different time zones

When to Call the Doctor

When should I contact my doctor about the basal body temperature method?

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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What happens to basal body temperature during ovulation

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What happens to basal body temperature during ovulation

Is your BBT higher or lower during ovulation?

It's lower in the first part of your cycle, and then rises when you ovulate. For most people, 96°– 98° Fahrenheit is their typical temperature before ovulation. After you ovulate, it goes up to 97°–99°F — about four-tenths of one degree higher than your usual temperature.

How many days after ovulation does temperature rise?

It can take up to three days after ovulation for the temperature to rise. However, in our experience most women experience temperature rises on the same day or a day later than when an ovulation predictor kit turns positive.

How long does basal temperature stay high after ovulation?

How long after ovulation does BBT rise? The bottom line: Basal body temperature typically elevates 12-14 hours post ovulation, but can take up to 3 days. In normal circumstances (and without a pregnancy) BBT will stay elevated 10-14 days post ovulation, up until the start of your period.