How does the menstrual cycle differ from the estrous cycle?

The menstrual cycle and the estrous cycle are both reproductive processes regulated by hormonal interactions between the pituitary gland and the ovaries, but they differ significantly in their physiological outcomes and behavioral manifestations.12

Key Differences

• Uterine Lining: In the menstrual cycle of higher primates, if fertilization does not occur, the thickened uterine lining (endometrium) is sloughed off and discharged from the body as menstrual blood. In the estrous cycle, the endometrium typically undergoes quiescence or is reabsorbed by the body if pregnancy does not occur, rather than being shed through vaginal bleeding.1342
• Receptivity: The estrous cycle is defined by a period of "heat" (estrus), during which the female is sexually receptive to the male and often exhibits behavioral signals of readiness to mate. In contrast, human females do not exhibit a distinct period of heat and are not limited to a specific window of sexual receptivity.512
• Cycle Continuity: Many mammals with estrous cycles experience a nonreproductive resting phase (anestrus) and may be monestrous (breeding once a year) or polyestrous. Higher primates typically experience an unbroken series of cycles throughout the year.512