A recurring process that occurs primarily in the endometrium of the uterus and is influenced by hormonal changes associated with the ovarian cycle. It consists of four distinct phases: the menstrual phase, the regenerative phase, the proliferative phase and the secretory phase. The duration of this cycle is usually from the first day of one menstrual period to the first day of the next, with the most common cycle lasting around 28 days, although it can naturally vary between 21 and 40 days. It is also known as endometrial cycle.