Basal Body Temperature

Understanding and Recording Basal Body Temperatures

New Berlin Infertility Treatment on how to record basal body temperatureBasal body temperature or “BBT” is the temperature of the body at rest. By recording your BBT on a daily basis, we can determine when and if ovulation occurs during your menstrual cycle.

Basal body temperature is obtained by taking your oral temperature first thing every morning PRIOR to rising, eating, drinking or using the bathroom. A basal body thermometer reads 0.1 degree units. A conventional thermometer reads in 0.2 degree units. You may also use an oral digital thermometer.

  1. Place the BASAL thermometer in your mouth, under your tongue for at least three minutes.
  2. Accurately read and record your temperature to the 0.1 degree in your chart

The Menstrual Cycle

Pre-ovulatory Phase

This time of your cycle begins on day one of your menstrual period. Your basal body temperature registers approximately 97 to 98 degrees at this time. Your ovaries are recruiting an egg follicle for ovulation.

Ovulatory Phase

In about one-third of normal cycles just prior to ovulation, you may notice a dip in your basal temperature of several tenths of a degree. At the time of ovulation, the mature egg is expelled from its follicle, drawn into the fallopian tube, contacts a sperm cell, and is fertilized. After the egg is expelled, its follicle becomes the corpus luteum. After ovulation, the cells in the corpus luteum produce a hormone called progesterone which causes a thermal shift in your basal temperature that promotes pregnancy. Therefore, following effective ovulation, your temperature rises. A rise of 0.4 to 0.6 degrees for three consecutive days strongly suggests that ovulation has occurred.

Other symptoms you may notice at the time of ovulation are an increase in vaginal mucus (due to high estrogen effect on cervical cells) and possible left or right-sided pelvic discomfort (due to a small amount of blood from the ovulating follicle). These symptoms should be noted on your temperature chart.

Luteal Phase

Progesterone continues to be secreted by the corpus luteum throughout this phase of your cycle. If pregnancy occurs, the basal body temperature remains high (about mid 98 degrees). If pregnancy does not occur, your temperature will drop and menses will begin approximately 14 days after ovulation.

How to Record an Accurate BBT Chart

  1. How to correctly record an accurate basal body temperature chartThe first full day of your menstrual cycle is considered DAY 1 of your cycle. It is helpful to fill in this information on your chart at the beginning of your period. Locate "day of the month" on the chart, and fill in the boxes going across with the month and day.
  2. Indicate each day of menstrual flow by blocking the square on the chart next to "menstruation". (Note: if bleeding for four days, block in days one through four on the chart). Days of spotting should be labeled "sp" in the appropriate box.
  3. Indicate days of intercourse by an arrow pointed down in the space provided. This will help the physician determine whether or not your timing was close to ovulation. The best time for intercourse is usually every other day while your temperature is rising until it remains elevated. The egg will survive approximately 12 hours, while the sperm can remain viable for 48 – 72 hours.
  4. If you are presently taking any medications such as Clomid, progesterone, hCG, etc., record it by placing an "X" on those days. Also, record the dosage of your medication in the left margin. Daily medications can also be indicated in the left margin.
  5. If you are not taking clomiphene and we are just monitoring your basal body temperature charts, you need to fax it to our office at 262-549-1657.
  6. If you are taking clomiphene and your menses starts, call our office to schedule an ultrasound between days 2 and 5 of your cycle. Bring your basal body temperature chart with you for the provider to evaluate along with your physical findings before renewing or increasing your clomiphene/letrozole prescription.
  7. Always record the following information on each chart: name and address, phone number (where you can be reached and your pharmacy), day/month/year of cycle, any medication taken and the amount, and mid-cycle intercourse events.
  8. Any obvious reasons for temperature variations such as colds, illness, insomnia, vacation, etc., should be noted on the graph above the reading for that day. Electric blankets and waterbed heaters may also alter temperature readings.
  9. We will be happy to provide you with additional charts when needed.
  10. If your period is late, please call us so that we can arrange for pregnancy testing as soon as possible.
  11. Please do not let your cycle go beyond 40 days. Call to let us know and we will rule out pregnancy. If a negative result occurs, we may induce a period so that your fertility workup is not prolonged.
  12. Do not be alarmed if your BBT chart does not look like the example shown. These charts provide us with individualized information about your cycle and will be of great value in our treatment for you as a couple.

Fertility care with basal body tempature charting

Contact Waukesha gynecologist at Women's Health Care 262-549-2229 for fertility care with the use of Basal Body Tempature charting