Basal Body Temperature Method (BBT)
Basal body temperature is the lowest temperature the body reaches during rest. Women will see a slight increase in basal body temperature during ovulation. It’s possible to predict fertile days by recording daily basal temperature on a chart for many months to see a pattern.
Each woman has a different basal body temperature and it can vary from 96 to 98 degrees Fahrenheit before the egg is released. After ovulation, it increases to 97 to 99 degrees Fahrenheit. The increase can happen from one day to the next or span several days.
How To Measure Basal Body Temperature
Temperature will only increase from four-tenths to eight-tenths of a degree during ovulation. Regular thermometers are not sensitive enough to detect this change, so a special basal body temperature thermometer is recommended. Digital thermometers are easier to read and will deliver more accurate results. Read the temperature to a 1/10 of a degree to get the most accurate assessment. Read the instructions included with the thermometer to learn how long to take your temperature each time.
Plot your temperature on a chart daily. After three or more months, you will see a pattern and can predict when ovulation will occur. If you are unable to read your chart, ask a doctor or nurse for help.
The spike in body temperature can’t predict ovulation, but it does show when the egg has been released. Body temperature will stay elevated until the next cycle when menstruation begins. Women are more likely to conceive two to three days before temperature reaches its highest point and for one day afterwards.
Spermatozoa can live in the vaginal cavity and fertilize the egg for days after ejaculation. Engaging in sexual activity in the days before ovulation can result in a pregnancy.
Getting An Accurate Temperature Reading
To get the most accurate temperature reading, measure your temperature at the same time each morning. Basal body temperature is affected by many things. Some of the variables that can affect temperature readings are:
- Drinking alcohol
- Smoking cigarettes
- Not getting enough sleep
- Cold or illness
If any of these events have occurred, take your temperature and make a note on the chart what happened.
Charting basal body temperature can take several months to see a pattern for some women. Temperature alone cannot predict when ovulation will occur, but it can tell you that it happened. If you are trying to avoid pregnancy, it’s best to use this method in conjunction with another method to predict ovulation.