Directions for Charting Basal Body Temperature (BBT)
- Use a digital basal body temperature thermometer (reads temps at 1/10 of a degree increments).
- Oral or vaginal reading are most accurate, but whichever method you choose you must continue using throughout a cycle
- Take and record your temperature every morning immediately upon awakening.
- Refrain from speaking or moving around prior to taking your temperature, as this will raise it significantly.
- Temperatures are most accurate after having at least 3 hours of uninterrupted sleep.
- On your chart, note any unusual circumstance that may have occurred such as illness, fever, lack of sleep, or alcohol consumption the night before. Each of these may account for otherwise unexplainable temperature changes.
- Note the days when you had fertile cervical mucus (Spinn) which should be wet and slippery around ovulation, like the consistency of egg white.
- Some people like to use the website for Fertility Friend for their charting, or you can download and copy the chart provided.
- A typical BBT chart for a cycle shows a rise of between 0.3 and 1.0 degree F after ovulation.
- Temperatures should remain elevated in this luteal phase for about 14 days. They will then stay high in a positive pregnancy, or drop just prior to the onset of menstruation.
Example of normal BBT chart for a 29 day cycle sample BBT chart