Medical Health Encyclopedia

Amenorrhea is the absence of menstruation. There are two categories: primary amenorrhea and secondary amenorrhea. These terms refer to the time when menstruation stops:

• Primary amenorrhea occurs when a girl does not begin to menstruate. Girls who show no signs of sexual development (breast development and pubic hair) by age 14 should be evaluated. Girls who do not have their periods by two years after sexual development should also be checked. Any girl who does not have her period by age 16 should be evaluated for primary amenorrhea.
• Secondary amenorrhea occurs when periods that were previously regular become absent for at least three cycles.

Oligomenorrhea (Light or Infrequent Menstruation)

Oligomenorrhea is a condition in which menstrual cycles are infrequent. It is very common in early puberty and does not usually indicate a medical problem. When girls first menstruate they often do not have regular cycles for a couple of years. Even healthy cycles in adult women can vary by a few days from month to month. In some women, periods may occur every three weeks and in others, every five weeks. Flow also varies and can be heavy or light. Skipping a period and then having a heavy flow may occur; this is most likely due to missed ovulation rather than a miscarriage. Women should be concerned when periods come less than 21 days or more than three months apart, or if they last more than ten days. Such events may indicate ovulation problems.

Premenstrual Syndrome (PMS)

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Premenstrual syndrome (PMS) is a set of physical, emotional, and behavioral symptoms that occur during the last week of the luteal phase (a week before menstruation) in most cycles. The symptoms typically do not start until at least day 13 in the cycle, and resolve within four days after bleeding begins. Women may begin to experience premenstrual syndrome symptoms at any time during their reproductive years. Once established, the symptoms tend to remain fairly constant until menopause, although they can vary from cycle to cycle. About 100 symptoms have been identified with the premenstrual phase. [For more information, see In-Depth Report #79: Premenstrual Syndrome.]