“…The human reproductive cycle or menstrual cycle with a period of approximately 28 days may influence daily circadian rhythms and may be an important consideration when studying female circadian rhythms. Some human studies evaluating the effect of the menstrual cycle on the circadian rhythm of body temperature (T b ) have shown mean T b increases during the luteal phase of the menstrual cycle [Cagnacci et al, 1996[Cagnacci et al, , 1997[Cagnacci et al, , 2002Driver et al, 1996;Lee, 1988;Severino et al, 1991], whereas others have reported that the amplitude of the T b rhythm decreases during the luteal phase in humans [Cagnacci et al, 1996[Cagnacci et al, , 1997[Cagnacci et al, , 2002Lee, 1988;Nakayama et al, 1997;Severino et al, 1991].…”