Circadian Temperature Rhythms in Relation to Menstrual Cycle Phase

Abstract

In order to describe circadian temperature rhythms in relation to female ovulatory cycles, a study was conducted in which continuous rectal temperature was monitored in healthy women at two phases of their menstrual cycles. Results indicate that, in addition to an increase in the mesor, there is a significant dampening of the temperature amplitude during the luteal (postovulatory) phase compared to the follicular (preovulatory) phase. In comparison with studies of male subjects, the average acrophase for females may occur about 2 hr earlier. Results from this study provide descriptive normative data, controlling for menstrual cycle phase, to which female clinical populations can be compared. The use of circadian tempera ture rhythm as a possible noninvasive diagnostic indicator of ovulation is also discussed.