How to Track Basal Body Temp

The average woman's body temperature is 96 to 98 degrees Fahrenheit when taken orally anytime between the first day of her period and ovulation. After women ovulate, their average body temperature runs from 97 to 99 degrees Fahrenheit due to changes in the production of the hormone progesterone. Ovulation means that the woman is able to conceive. Since this only happens once a month for a period of one to three days, couples hoping to get pregnant are advised to look for temperature patterns in menstrual cycles in order to isolate the window of fertility. The best way to look for this rise in temperature is to measure body temperature first thing in the morning before you've engaged in any of the day's activities. This type of measurement is known as basal body temperature. Other ways to track fertility include tracking the beginning and length of monthly periods and measuring cervical mucus.

Things You'll Need

• Basal Body Temperature Chart Basal Body Thermometer

Show More

Instructions

• 1

  Obtain a copy of a basal body temperature chart. Your family doctor or obstetrician/gynecologist may provide you with one of these. If not, you can print one out from various websites (see Resources). Place the chart in a place where you can refer to it on a daily basis.

• 2

  Purchase a basal body thermometer. You can find these at most pharmacies, or you can order one online (see Resources). The thermometers run from $5 to $10. A basal body thermometer is more sensitive than a standard oral thermometer. Most women only experience a 0.4 to 0.8 degree change in temperature right after ovulation, so it's necessary to have as much accuracy as possible when measuring such a slight change.

• 3

  Use the basal body thermometer to take your temperature first thing in the morning on the first day of your period, "day 1". Make sure you've had at least three to four hours sleep. Take the measurement while lying down, before you've done any activity, including eating, drinking or going to the bathroom. Record your temperature on the basal body temperature chart. Mark your temperature by placing a dot above day 1 in the spot that corresponds with the correct temperature.

• 4

  Take your basal body temperature on the second day of your period at the exact same time of morning as you did on day 1 (or as close to the exact same time as possible). Mark this reading on "day 2" of chart. Continue this every single day for the entire month. Ideally, continue this tracking process for at least two to three months.

• 5

  Interpret your data. At the end of the month, you should notice a day when your basal body temperature rose by 0.4 to 0.8 degrees and remained elevated for the rest of your cycle. This indicates when you just finished ovulating. Use data from multiple months in order to look for your personal patterns. If your temperature rises on or about the same day of your cycle each month, then you know that you are ovulating anywhere from one to three days before that day of elevated temperature. These one to three days are the days you are most likely to conceive.