ABSTRACT
MENSTRUAL CYCLE The endometrium is the mucous membrane lining the uterine cavity. In fertile women, it undergoes a series of changes, ending roughly every month in mucosal loss, accompanied by uterine bleeding per vaginam. This menstrual or monthly period refers to lunar calendars. The phasic lunar cycle lasts 29Y/2 days; the sidereal peri od of the lunar cycle is 27ІІз days. But the endometrial changes are under the direct control of the ovarian hor mones, controlled by the pituitary gland.
