Menstrual Disorders Understanding Menstruation

What is a Menstrual Cycle?

A woman’s body usually prepares for pregnancy about every 28 days. Each woman’s body is unique but, in general, the menstrual cycle is considered to begin on the first day of bleeding and continue to the first day of the next period. For some women, a menstrual cycle is as short as 21 days or as long as 35 days and for some women, each month may be different from the last. What one woman might consider an irregular menstrual cycle another woman might consider normal.

About mid-cycle, a woman’s body releases an egg from the ovaries down the fallopian tubes and towards the uterus. The lining of the uterus prepares for pregnancy by thickening. If the egg remains unfertilized (if no sperm reaches it), the extra blood and tissue that formed in the uterus is shed—this is what women call their “period.” Then a new menstrual cycle begins.

More About Periods

Average 28-day menstrual cycleSomewhere between the ages of eight and sixteen, most girls in the United States begin menstruation. The average age is about twelve, but this average has been getting younger in recent years. The beginning of a girl’s first menstrual cycle is called menarche.

Menstrual periods may last from three to seven days or, in some cases, even longer. Some women have an irregular menstrual cycle for several years; others are as regular as rain from menarche to menopause.

Keeping a Menstruation Calendar

Maintaining a menstrual cycle journal or menstruation calendar will help you determine the length of your cycle. Each month, mark the first day of your period. After several months, count the days between periods and calculate the length of your cycle. Knowing when to expect your period can help you prepare: eat right, exercise regularly and keep sanitary supplies handy when your period approaches.

Different birth control treatments are often used to help regulate your period. Talk with your doctor to see if one is right for you.

Irregular Menstrual Cycles

Some degree of irregularity in the menstrual cycle is familiar to the vast majority of menstruating women. The four types of menstrual irregularities are:

  • Amenorrhea: absence of periods
  • Oligomenorrhea: infrequent menstruation
  • Dysmenorrhea: severe menstrual cramping
  • Menorrhagia: excessive menstrual bleeding.

Premenstrual Disorders

Women regularly suffer from more than 150 premenstrual and menstrual discomforts, ranging from water retention and breast tenderness to severe cramping and migraine headache. Feeling just plain grumpy and experiencing mood swings is also part of the gamut of PMS symptoms.

When Do I Seek Medical Advice?

If your menses haven’t started by age sixteen, you’ve stopped having your period at a young age, or you’re concerned about any of the above aspects of irregularity, contact your family practitioner or gynecologist.

But these symptoms should not be confused with premenstrual dysphoric disorder, or PMDD, which is a psychiatric term for a major premenstrual mood disturbance that occurs in three to eight percent of women.


Davidson, T. (1999). Oligomenorrhea. Gale Encyclopedia of Medicine. Retrieved August 16, 2002, from html?term=Oligomenorrhea.

The Thomson Corporation. (2001). Oligomenorrhea. Retrieved August 17, 2002, from