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.
• Gonadotropin-releasing hormone stimulates the pituitary gland to produce two hormones called gonadotropins: luteinizing hormone and follicle-stimulating hormone.
• Luteinizing hormone and follicle-stimulating hormone stimulate the ovaries.
• The ovaries produce the female hormones estrogen and progesterone, which ultimately control menstruation (see Biology of the Female Reproductive System: Menstrual Cycle).

Hormones produced by other glands, such as the adrenal glands and the thyroid gland, can also affect the functioning of the ovaries and menstruation.

During the reproductive years, vaginal bleeding may be abnormal 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.

Menstrual disorders include premenstrual syndrome, dysmenorrhea, dysfunctional uterine bleeding, and amenorrhea.

Deciphering Medical Terms for Menstrual Disorders* Term Description Amenorrhea No periods Dysmenorrhea Painful periods Hypomenorrhea Unusually light periods Menometrorrhagia Prolonged bleeding that occurs at irregular intervals Menorrhagia, or hypermenorrhea 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 *Breaking the words into their components helps decipher them: a = no; dys = painful (or abnormal); hypo = deficient (or below normal); men = month; metro = uterus; oligo = few or scanty; poly = many or much; post = after; pre = before; rhagia = to burst forth; rhea = flow.

Last full review/revision December 2008 by JoAnn V. Pinkerton, MD