Dysmenorrhea is pelvic pain during a menstrual period.

About three fourths of women with dysmenorrhea have primary dysmenorrhea, for which no cause can be identified. The rest have secondary dysmenorrhea, for which a cause is identified.

Primary dysmenorrhea may affect more than 50% of women, usually starting during adolescence. In about 5 to 15%, primary dysmenorrhea is sometimes severe, interfering with daily activities and resulting in absence from school or work. Primary dysmenorrhea may become less severe with age and after pregnancy.

In primary dysmenorrhea, the pain occurs only during menstrual cycles in which an egg is released. The pain is thought to result from prostaglandins released during menstruation. Prostaglandins are hormonelike substances that cause the uterus to contract, reduce the blood supply to the uterus, and increase the sensitivity of nerve endings in the uterus to pain. Women who have primary dysmenorrhea have higher levels of prostaglandins.

Common causes of secondary dysmenorrhea include endometriosis, fibroids, adenomyosis, pelvic congestion syndrome, and pelvic infection. In a few women, the pain results from passage of menstrual blood through a narrow cervix (cervical stenosis). A narrow cervix may be present at birth or result from removal of polyps or treatment of a precancerous condition (dysplasia) or cancer of the cervix. Abdominal pain due to other disorders, such as inflammation of the fallopian tubes or abnormal bands of fibrous tissue (adhesions) between structures in the abdomen, may be worse during a menstrual period.

Adenomyosis: Noncancerous Growth of the Uterus In adenomyosis, glandular tissue from the lining of the uterus (endometrium) grows into the muscular wall of the uterus. The uterus becomes enlarged, sometimes doubling or tripling in size. This common disorder causes symptoms in only a small percentage of women, usually between the ages of 35 and 50. It is more common among women who have had children. The cause is unknown. Symptoms include heavy and painful periods, bleeding between periods, vague pain in the pelvic area, and a feeling of pressure on the bladder and rectum. Sometimes sexual intercourse is painful. Doctors suspect adenomyosis when they perform a pelvic examination and discover that the uterus is enlarged, round, and softer than normal. Pelvic ultrasound or magnetic resonance imaging (MRI) helps confirm the diagnosis. Sometimes when adenomyosis causes abnormal bleeding, a biopsy is performed. Usually, no treatment is effective, although oral contraceptives and gonadotropin-releasing hormone agonists (such as leuprolide or goserelin) may be tried. Analgesics may be taken for pain. In some cases, a hysterectomy may be performed.

Symptoms and Diagnosis

Pain occurs in the lower abdomen and may extend to the lower back or legs. The pain is usually crampy and comes and goes, but it may be a dull, constant ache. Usually, the pain starts shortly before or during the menstrual period, peaks after 24 hours, and subsides after 2 days. Other common symptoms include headache, nausea, constipation, diarrhea, and an urge to urinate frequently. Occasionally, vomiting occurs. Premenstrual irritability, nervousness, depression, and abdominal bloating may persist during part or all of the menstrual period.

Diagnosis is based on symptoms and the results of a physical examination. To identify possible causes (such as fibroids), doctors may examine the abdominal cavity using a viewing tube (laparoscope) inserted through a small incision just below the navel. They may examine the interior of the uterus using a similar tube (hysteroscope) inserted through the vagina and cervix. Other procedures may include dilation and curettage (D and C) and hysterosalpingography (see Symptoms and Diagnosis of Gynecologic Disorders: Dilation and Curettage and Symptoms and Diagnosis of Gynecologic Disorders: Hysterosalpingography).

Treatment

Nonsteroidal anti-inflammatory drugs (NSAIDs) usually relieve pain effectively. NSAIDs may be more effective if started 1 or 2 days before a menstrual period begins and continued for 1 or 2 days after it begins. An antiemetic drug may relieve nausea and vomiting, but these symptoms usually disappear without treatment as the pain subsides. Getting enough rest and sleep and exercising regularly may also help relieve symptoms.

If the pain continues to interfere with daily activities, oral contraceptives that contain estrogen in a low dose plus a progestin may be prescribed to suppress the release of eggs from the ovaries (ovulation). If these treatments are ineffective, procedures to identify the cause of the pain may be performed.

When dysmenorrhea results from another disorder, that disorder is treated if possible. A narrow cervical canal can be widened surgically. However, this operation usually relieves the pain only temporarily. If needed, fibroids or misplaced endometrial tissue (due to endometriosis) is surgically removed.

When other treatments are ineffective and the pain is severe, the nerves to the uterus may be cut surgically. However, this operation occasionally injures other pelvic organs, such as the ureters. Alternatively, hypnosis or acupuncture may be tried.

What Is Pelvic Congestion Syndrome? Sometimes pain that occurs before or during menstrual periods results from a problem with veins in the pelvis. The veins may widen and become convoluted and blood accumulates in them. The result is varicose veins in the pelvis—a disorder called pelvic congestion syndrome. Pain, sometimes debilitating, can result. Estrogen may contribute because it causes some veins supplying the ovaries and uterus to widen. Up to 15% of women of reproductive age have varicose veins in their pelvis, but not all of them have symptoms. Typically, the pain is dull and aching, but it may be sharp or throbbing. It is worse at the end of the day (after a woman has been sitting or standing a long time) and is relieved when she lies down. The pain is also worse during or after sexual intercourse. It is often accompanied by low back pain, aches in the legs, abnormal menstrual bleeding, and a vaginal discharge. Occasionally, fatigue, mood swings, headache, and abdominal bloating occur. Doctors may suspect pelvic congestion syndrome when a woman has pelvic pain but a pelvic examination does not detect inflammation or another abnormality. Ultrasonography can help doctors confirm the diagnosis. Alternatively, the veins can be viewed with a viewing tube inserted through a small incision just below the navel in a procedure called laparoscopy. Nonsteroidal anti-inflammatory drugs (NSAIDs) usually relieve the pain.

Last full review/revision February 2003