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THE MERCK MANUAL MEDICAL LIBRARY: The Merck Manual of Medical Information--Home Edition
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Complex interactions among hormones control the start of menstruation during puberty, the rhythms and duration of menstrual cycles during the reproductive years, and the end of menstruation at menopause. Hormonal control of menstruation begins in the hypothalamus (the part of the brain that coordinates and controls hormonal activity). The hypothalamus releases gonadotropin-releasing hormone in pulses. This hormone stimulates the pituitary gland to produce two hormones called gonadotropins: luteinizing hormone and follicle-stimulating hormone. These hormones stimulate the ovaries. The ovaries produce the female hormones estrogen and progesterone (see Biology of the Female Reproductive System: Menstrual Cycle), which ultimately control menstruation. Hormones produced by other glands, such as the adrenal glands and the thyroid gland, can also affect the functioning of the ovaries and menstruation.

Menstrual disorders include premenstrual syndrome, dysmenorrhea, and amenorrhea. Vaginal bleeding may be abnormal during the reproductive years when menstrual periods are too heavy or too light, last too long, occur too often, or are irregular. Any vaginal bleeding that occurs before puberty or after menopause is abnormal until proven otherwise.

Deciphering Medical Terms for Menstrual Disorders

Term

Description

Amenorrhea Absence of periods
Dysmenorrhea Painful periods
Hypomenorrhea Unusually light periods
Menometrorrhagia Prolonged bleeding that occurs at irregular intervals
Menorrhagia Unusually long and heavy periods
Metrorrhagia Bleeding that occurs at frequent, irregular intervals
Oligomenorrhea Unusually infrequent periods
Polymenorrhea Unusually frequent periods
Postmenopausal bleeding Bleeding that occurs after menopause
Premenstrual syndrome (PMS) Physical and psychologic symptoms that occur before the start of a period
Primary amenorrhea No periods ever starting at puberty
Secondary amenorrhea Periods that have stopped

Last full review/revision February 2003

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