Skip to main content Skip to Search Box

Definition: menstruation from The Penguin Dictionary of Psychology

The periodic discharge of blood and uterine material in mature women. This term and menses are often treated as synonyms, although occasionally the latter is restricted in meaning to the actual flow or discharge. See MENSTRUAL CYCLE for details.


Summary Article: menstruation from The Columbia Encyclopedia

periodic flow of blood and cells from the lining of the uterus in humans and most other primates, occurring about every 28 days in women. Menstruation commences at puberty (usually between age 10 and 17). The onset of menstruation, called menarche, signals the body's coming readiness for childbearing. It continues, unless interrupted by pregnancy until menopause (around age 50).

The Menstrual Cycle

In the first phase of each cycle, the lining, or endometrium, of the uterus undergoes rapid proliferation of cells and venous channels in preparation for pregnancy. Midway through the cycle an ovum (egg) is released from an ovary. If, while passing through the fallopian tube the ovum is fertilized by a sperm, implantation in the uterus occurs and the thickened lining helps support the pregnancy. When the ovum is not fertilized, this tissue and blood are shed. The proliferation of the uterine wall then begins once more in expectation of the next release of an ovum, and if conception does not take place, it sloughs off again. The process continues monthly until pregnancy occurs or until ovulation ceases at menopause.

The natural rhythm of the menstrual cycle may be broken or temporarily halted by hormonal imbalance, malnutrition, illness, or emotional disturbance (see amenorrhea). Menstruation is controlled by the hypothalamus and the pituitary gland and hormones, such as estrogen, which prepares the lining of the uterus, and progesterone, which helps maintain a pregnancy.

Dysmenorrhea and Premenstrual Syndrome

Many women experience painful menstruation, or dysmenorrhea. The uterine contractions that result in the cramps experienced by these women appear to be caused by hormones called prostaglandins that are produced in the second half of the cycle. Oral contraceptives and other drugs that reduce the production of prostaglandins are sometimes used in treatment. Other women experience symptoms such as behavioral changes, breast tenderness, and fatigue during the week immediately preceding menstruation, a condition referred to as premenstrual syndrome, or PMS.

Bibliography
  • See publications of the National Institute of Child Health and Human Development; Boston Women's Health Book Collective, Our Bodies, Ourselves for the New Century (1998).
The Columbia Encyclopedia, © Columbia University Press 2017

Related Credo Articles

Full text Article Menstruation
Encyclopedia of Women and Gender: Sex Similarities and Differences and the Impact of Society on Gender

I. The Cultural View of Menstruation II. The Biology of Menstruation III. Menstruation and Mood Glossary Endometrium...

Full text Article Menstruation
The Concise Corsini Encyclopedia of Psychology and Behavioral Science

Menstruation refers to normal vaginal bleeding that is usually monthly. The endometrium (uterus lining) sheds when a woman is not pregnant....

Full text Article menstruation
The Macmillan Encyclopedia

The monthly discharge of blood and fragments of womb lining from the vagina. This is part of the menstrual cycle— the sequence of...

See more from Credo