The recurring cycle of physiological changes in the uterus, ovaries, and other sexual structures that occur from the beginning of one menstrual period through the beginning of the next.
The recurring monthly series of physiological changes in women and other female primates in which an egg is produced in the process known as ovulation, and the uterine lining thickens to allow for implantation if fertilization occurs. If the egg is not fertilized, the lining of the uterus breaks down and is discharged during menstruation. See also ovulationmenstruation.
The periodic series of changes in the female reproductive system associated with the preparation of the uterus for pregnancy; the cycle is repeated roughly every twenty-eight days. During the menstrual cycle, an ovum is released from one of the ovaries (the release is called ovulation), and the uterus develops an inner lining enriched with blood to prepare it for the possible implantation of a zygote. If fertilization and implantation do not take place, the lining of the uterus is discharged during menstruation.
