- The periodic blood that flows as a discharge from the uterus. Also called menorrhea, the time during which menstruation occurs is referred to as menses. The menses occurs at approximately 4 week intervals to compose the menstrual cycle.
* * *Cyclic endometrial shedding and discharge of a bloody fluid from the uterus during the menstrual cycle. [see menstruate]- anovular m. menstrual bleeding without recent ovulation; also occurs in subhuman primates. SYN: anovulational m., nonovulational m..- anovulational m. SYN: anovular m..- nonovulational m. SYN: anovular m..- retained m. SYN: hematocolpos.- retrograde m. a flow of menstrual blood back through the fallopian tubes; it sometimes carries with it endometrial cells.- supplementary m. bleeding from the navel or urinary tract due to endometriosis occurring at the time of m..- vicarious m. bleeding from any surface other than the mucous membrane of the uterine cavity, occurring periodically at the time when the normal m. should take place.
* * *men·stru·a·tion .men(t)-strə-'wā-shən, men-'strā- n a discharging of blood, secretions, and tissue debris from the uterus that recurs in nonpregnant human and other primate females of breeding age at approximately monthly intervals and that is considered to represent a readjustment of the uterus to the nonpregnant state following proliferative changes accompanying the preceding ovulation also PERIOD (1b)
* * *(menses)n.the discharge of blood and of fragments of endometrium from the vagina at intervals of about one month in women of child-bearing age (see menarche, menopause). Menstruation is that stage of the menstrual cycle during which the endometrium, thickened in readiness to receive a fertilized egg cell (ovum), is shed because fertilization has not occurred. The normal duration of discharge varies from three to seven days. In anovular menstruation, discharge takes place without previous release of an egg cell from the ovary. Vicarious menstruation is bleeding from a mucous membrane other than the endometrium when normal menstruation is due. Retrograde menstruation is the backflow of blood and endometrial cells through the Fallopian tubes (see endometriosis). See also amenorrhoea, dysmenorrhoea, epimenorrhoea, hypomenorrhoea, menorrhagia, oligomenorrhoea.
* * *men·stru·a·tion (men″stroo-aґshən) the cyclic, physiologic discharge through the vagina of blood and mucosal tissues from the nonpregnant uterus; it is under hormonal control and normally recurs, usually at approximately four-week intervals, in the absence of pregnancy during the reproductive period (puberty through menopause) of the female of the human and a few species of primates. It is the culmination of the menstrual cycle; see illustration under cycle.
Medical dictionary. 2011.