menstruation

Meaning of menstruation: Menstruation is the cyclical shedding of the uterine lining that occurs when pregnancy does not take place, recurring throughout the reproductive years.

Definition of menstruation

Menstruation is the periodic discharge of blood and tissue from the uterus that occurs when the uterine lining, built up during the earlier part of the menstrual cycle in preparation for a possible pregnancy, is shed because pregnancy has not occurred. It is regulated by a cycle of rising and falling hormones, including estrogen and progesterone.

Menstruation typically begins at puberty and continues on a recurring basis until menopause, with cycle length varying between individuals and even from one cycle to the next in the same person, generally recurring at intervals of roughly three to five weeks. The bleeding phase itself usually lasts several days.

Menstruation stops during pregnancy, since the uterine lining is instead maintained to support the developing pregnancy, and changes in menstrual pattern, such as unusually heavy bleeding, missed periods, or bleeding at other times in the cycle, can reflect a range of underlying hormonal or structural causes worth further evaluation.