Charting your BBT

Reading your BBT Chart

1. After you see a temperature shift for at least three days, or at the end of your cycle, you can draw a coverline between your follicular phase and luteal phase temperatures. With luck, it is easy to see a clear shift and draw your line between the highest follicular phase BBT and the lowest luteal phase BBT as in the sample.
2. Review your chart and determine the day within your cycle that you ovulated.
3. Count the length of your luteal phase as the number of days past ovulation (DPO), and before your menstrual period began.
4. Chart for a few months and look for patterns.
5. If your temperature stays up for 18 days or more after ovulation, you should test for pregnancy.

If your cycle length is irregular, you should find that the length of your follicular phase varies, but that your luteal phase remains relatively constant (within 1-2 days). For example, if your cycle ranges from 28-34 days each month, your luteal phase may consistently be 14 days, meaning that your ovulation occurs somewhere between days 14-20 each month - day 14 when your cycle is 28 days long, and day 20 when your cycle is 34 days long.