Because temperature increases
slightly after ovulation (the luteal phase), then dips to pre-ovulation temperatures just before the start of a new cycle (the follicular phase), it's possible to track where each volunteer was in her menstrual cycle on any given day.
Not exact matches
This is one of the easiest ways to track your
ovulation cycle as just before
ovulation your basal body temperature will lower
slightly, then rocket back up to warmer than normal right
after ovulation has passed.
In addition, the female body is naturally
slightly less insulin sensitive when progesterone levels are higher in the luteal phase (
after ovulation, in the last two weeks of the cycle).
As you chart your BBT daily, you will notice your chart will become «biphasic», meaning that it will show relatively low temperatures before
ovulation and
slightly higher temperatures
after ovulation.