Dysmenorrhea is pelvic pain during a menstrual period. For some women, the discomfort is merely annoying. For others, it can be severe enough to interfere with everyday activities for a few days every month.

Dysmenorrhea can be primary or secondary. Primary dysmenorrhea involves no physical abnormality. These so-called normal cramps affect 50 percent to 90 percent of all menstruating women. Primary dysmenorrhea usually begins within three years after a girl begins menstruating. Secondary dysmenorrhea involves an underlying physical cause, such as endometriosis or uterine fibroids.

If you have primary dysmenorrhea, there are some measures you can take to ease the discomfort. You also can take comfort in knowing that cramps tend to decrease in intensity as you get older, and often disappear after a pregnancy. For secondary dysmenorrhea, managing your cramps involves treating the underlying cause.

• Endometriosis

Signs and symptoms

Cramps become problematic when they're severe enough to keep you from going about your day-to-day routine.

If you have primary dysmenorrhea, cramps most likely began within three years after you started menstruating. They may persist through your 20s or until you deliver a child; then they're likely to decrease in intensity or go away entirely, for unknown reasons. With secondary dysmenorrhea, cramps may start or return later in life, but can begin anytime after you begin menstruating.

Signs and symptoms of dysmenorrhea, whether primary or secondary, may include:

• Dull or throbbing pain in your lower abdomen

• Pain that radiates to your lower back and thighs

Less common signs and symptoms include:

• Nausea and vomiting

• Loose stools

• Sweating

• Dizziness

• Endometriosis

• Nausea

• vomiting

Causes

To create a nourishing environment for a fertilized egg, the female sex hormone estrogen causes your uterine lining (endometrium) to thicken every month. Soon after, a follicle — a tiny sac in your ovary that contains a single egg (ova) — ruptures and releases its egg (ovulation). If the egg becomes fertilized by contact with a sperm on its way to your uterus, the egg implants in the lining of the uterus. However, most often the unfertilized egg passes through your uterus and out of your body. Shortly thereafter, your uterus releases the lining, and your menstrual flow begins.

To help expel its lining, your uterus contracts. Prostaglandins, hormone-like substances involved in pain and inflammation, trigger the uterine muscle contractions. No one knows for sure, but many experts believe that prostaglandins cause menstrual cramps (primary dysmenorrhea).

A number of conditions can cause secondary dysmenorrhea. They include:

• Endometriosis. In this painful condition, the type of tissue that lines your uterus becomes implanted outside your uterus, most commonly on your fallopian tubes, ovaries or the tissue lining your pelvis.

• Pelvic inflammatory disease. This infection of the female reproductive organs is usually caused by sexually transmitted bacteria.

• Use of an intrauterine device (IUD). These small, plastic, T-shaped birth control devices are inserted into your uterus.

• Uterine fibroids and uterine polyps. These noncancerous tumors and growths protrude from the lining of your uterus.

Risk factors

You're more likely to have severe menstrual cramps if you have one or both of the following:

• A family history of painful periods

• Early onset of puberty (age 11 or younger)

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