Figure 1
Continuous core body temperature (CCBT) collected during the menstrual cycle reveal an infradian rhythm and pattern. The fine purple line represents a cosinor fit of continuous core body temperature influenced by the combined effect of estrogen and progesterone. Arrows indicate the predominate influence of estrogen in the peri-ovulatory period of the follicular phase and the predominate influence of progesterone in the luteal phase. Analysis of the change in phase, amplitude and mesor of CCBT predict and identify the window of fertility and day of ovulation and mensus.