Menstrual cramps are pains in the lowest part of the torso (pelvis), a few days before, during, or after a menstrual period. The pain tends to be most intense about 24 hours after periods begin and to subside after 2 to 3 days. The pain is usually crampy or sharp and comes and goes, but it may be a dull, constant ache. It sometimes extends to the lower back and legs.
Many women also have a headache, nausea (sometimes with vomiting), and constipation or diarrhea. They may need to urinate frequently.
Symptoms of premenstrual syndrome (such as irritability, nervousness, depression, fatigue, and abdominal bloating) may persist during part or all of the menstrual period.
Sometimes menstrual blood contains clots. The clots, which may appear bright red or dark, may contain tissue and fluid from the lining of the uterus, as well as blood.
Symptoms tend to be more severe if
Causes
Menstrual cramps may
Primary dysmenorrhea usually starts during adolescence and may become less severe with age and after pregnancy. It is more common than secondary dysmenorrhea.
Secondary dysmenorrhea usually starts during adulthood unless it is caused by a birth defect.
Common causes
More than 50% of women with dysmenorrhea have
In about 5 to 15% of these women, cramps are severe enough to interfere with daily activities and may result in absence from school or work.
Experts think that primary dysmenorrhea may be caused by release of substances called prostaglandins during menstruation. Prostaglandin levels are high in women with primary dysmenorrhea. Prostaglandins may cause the uterus to contract (as occurs during labor), reducing blood flow to the uterus. These contractions can cause pain and discomfort. Prostaglandins also make nerve endings in the uterus more sensitive to pain.
Lack of exercise and anxiety about menstrual periods may also contribute to the pain.
Secondary dysmenorrhea is commonly caused by
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Endometriosis: Tissue that normally occurs only in the lining of the uterus (endometrial tissue) appears outside the uterus. Endometriosis is the most common cause of secondary dysmenorrhea.
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Fibroids: These noncancerous tumors are composed of muscle and fibrous tissue and grow in the uterus.
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Adenomyosis: Endometrial tissue grows into the wall of the uterus, causing it to enlarge and swell during menstrual periods.
Less common causes
There are many less common causes of secondary dysmenorrhea. They include
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Birth defects
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Cysts and tumors in the ovaries
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Use of an intrauterine device (IUD) that releases copper or a progestin (a synthetic form of the female hormone progesterone)
IUDS that release a progestin cause less cramping than those that release copper.
In a few women, pain occurs because the passageway through the cervix (cervical canal) is narrow. A narrow cervical canal (cervical stenosis) may develop after a procedure, as when a polyp in the uterus is removed or a precancerous condition (dysplasia) or cancer of the cervix is treated. A growth (polyp or fibrosis) can also narrow the cervical canal.
Evaluation
Doctors usually diagnose dysmenorrhea when a woman reports that she regularly has bothersome pain during menstrual periods. They then determine whether dysmenorrhea is primary or secondary.
Doctors must check for two serious disorders that can also cause pelvic pain:
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An abnormally located pregnancy (ectopic pregnancy)—that is, one not in its usual location in the uterus
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Pelvic inflammatory disease―infection of the uterus and/or fallopian tubes and sometimes the ovaries
Doctors can usually identify these disorders because the pain and the other symptoms they cause typically differ from those of dysmenorrhea.
An ectopic pregnancy usually causes sudden pain that begins in a specific spot and is constant (not crampy). It may or may not be accompanied by vaginal bleeding. The pain may become severe. If the ectopic pregnancy ruptures, women may feel light-headed, faint, have a racing heart, or go into shock.
In pelvic inflammatory disease, the pain may become severe and may be felt on one or both sides. Women may also have a foul-smelling, puslike discharge from the vagina, vaginal bleeding, or both. Sometimes women have a fever, nausea or vomiting, or pain during sexual intercourse or urination.
Warning signs
When to see a doctor
Women with any warning sign should see a doctor that day.
If women without warning signs have more severe cramps than usual or have pain that lasts longer than usual, they should see a doctor within a few days.
Other women who have menstrual cramps should call their doctor. The doctor can decide how quickly they need to be seen based on their other symptoms, age, and medical history.
What the doctor does
Doctors or other health care practitioners ask about the pain and the medical history, including the menstrual history. Practitioners then do a physical examination. What they find during the history and physical examination may suggest a cause of menstrual cramps and the tests that may need to be done (see table Some Causes and Features of Menstrual Cramps).
For a complete menstrual history, practitioners ask the woman
Practitioners also ask the woman the following:
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How old she was when symptoms began
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What other symptoms she has
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What the pain is like, including how severe it is, what relieves or worsens symptoms, and how symptoms interfere with her daily activities
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Whether she has pelvic pain unrelated to periods
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Whether acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) help relieve the pain
The woman is asked whether she has or has had disorders and other conditions that can cause cramps, including use of certain drugs (such as birth control pills) or an IUD. She is also asked about physically or emotionally traumatic experiences, such as sexual abuse. Practitioners ask whether she has had any surgical procedures that increase the risk of pelvic pain, such as a procedure that destroys or removes the lining of the uterus (endometrial ablation).
A pelvic examination is done. Doctors check the vagina, vulva, cervix, uterus, and the area around the ovaries for abnormalities, including polyps and fibroids.
Doctors also gently feel (palpate) the abdomen to check for areas of particular tenderness, which may indicate severe inflammation in the abdomen (peritonitis).
Some Causes and Features of Menstrual Cramps
Cause |
Common Features* |
Tests |
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Adenomyosis (growth of tissue that normally lines the uterus—called endometrial tissue—into the wall of the uterus) |
Heavy, painful periods, vaginal bleeding between periods, pain in the lowest part of the torso (pelvis), and a feeling of pressure on the bladder and rectum Sometimes pain during sexual intercourse |
Ultrasonography or MRI of the pelvis In women with abnormal vaginal bleeding, sometimes a biopsy to rule out other causes of bleeding |
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Birth defects of the reproductive tract |
Sometimes abnormalities found during the pelvic examination, such as genitals that feel or look abnormal or a lump in the pelvis |
A doctor's examination Sometimes hysterosalpingography (x-rays taken after a contrast agent is injected into the uterus and fallopian tubes), sonohysterography (ultrasonography after fluid is infused into the uterus), or MRI |
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Cervical stenosis (narrowing of the passageway through the cervix) |
Irregular or no menstrual periods, vaginal bleeding between periods, infertility, and abdominal pain that occurs in cycles Possibly bulging of the vagina or uterus |
A doctor's examination Sometimes ultrasonography of the pelvis |
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Cysts and tumors in the ovaries (ovarian cancer or noncancerous ovarian growths) |
Often no other symptoms Sometimes abnormal vaginal bleeding If cancer is advanced, sometimes indigestion, bloating, and backache |
Transvaginal ultrasonography (using a handheld device inserted into the vagina) If cancer is suspected, blood tests to measure substances produced by certain tumors |
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Endometriosis (patches of endometrial tissue that are abnormally located outside the uterus) |
Sharp or crampy pain that occurs before and during the first days of menstrual periods Infertility Often pain during sexual intercourse, bowel movements, or urination |
A doctor's examination Sometimes laparoscopy (insertion of a viewing tube through a small incision just below the navel) Sometimes ultrasonography of the pelvis or MRI |
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Often no other symptoms With large fibroids, sometimes pain, pressure, abnormal vaginal bleeding, or a feeling of heaviness in the pelvic area |
Ultrasonography Sometimes sonohysterography or hysteroscopy (use of a thin viewing tube to see the interior of the uterus) If results are unclear, MRI |
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Intrauterine devices (IUDs) that release copper or, less often, a progestin (a synthetic form of the female hormone progesterone) |
Pain and vaginal bleeding that often subside several months after insertion of the IUD |
A doctor's examination Usually ultrasonography of the pelvis to determine whether the IUD is correctly placed in the uterus |
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Pelvic congestion syndrome (chronic pain due to accumulation of blood in veins of the pelvis) |
Pain that is Often low back pain, aches in the legs, and abnormal vaginal bleeding Occasionally a clear or watery discharge from the vagina Sometimes fatigue, mood swings, headaches, and bloating |
A doctor’s examination Ultrasonography or specialized imaging techniques Sometimes laparoscopy |
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Vaginal bleeding or discharge |
A doctor's examination Sometimes ultrasonography of the pelvis, sonohysterography, or hysteroscopy |
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* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. |
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MRI = magnetic resonance imaging. |
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Testing
Testing is done to rule out disorders that may be causing the pain. For most women, tests include
If pelvic inflammatory disease is suspected, a sample of secretions is taken from the cervix, examined under a microscope, and sent to a laboratory to be tested.
If these tests are inconclusive and symptoms persist, one or more of the following tests is done:
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Hysterosalpingography or sonohysterography to identify polyps, fibroids, and birth defects
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Magnetic resonance imaging (MRI) to identify other abnormalities or, if surgery is planned, to provide more information about previously identified abnormalities
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Hysteroscopy to identify problems with the cervix or uterus (but not with the ovaries)
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Laparoscopy if needed
For hysterosalpingography, x-rays are taken after a substance that can be seen on x-rays (radiopaque contrast agent) is injected through the cervix into the uterus and fallopian tubes.
For sonohysterography, ultrasonography is done after fluid is infused in the uterus through a thin tube inserted through the vagina and cervix. The fluid makes abnormalities easier to identity.
For hysteroscopy, doctors insert a thin viewing tube through the vagina and cervix to view the interior of the uterus. This procedure can be done in a doctor's office or in a hospital as an outpatient procedure.
For laparoscopy, a viewing tube is inserted through a small incision just below the navel and is used to view the uterus, fallopian tubes, ovaries, and organs in the abdomen. This procedure is done in a hospital or surgical center.
If results of hysterosalpingography or sonohysterography are inconclusive, hysteroscopy or laparoscopy can be done. Both hysteroscopy and laparoscopy enable doctors to directly view structures in the pelvis. Laparoscopy enables doctors to examine all of the pelvis and reproductive organs.
Treatment
When menstrual cramps result from another disorder, that disorder is treated if possible. For example, 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 doctors diagnose primary dysmenorrhea, they reassure women that no other disorder is causing the pain and recommend general measures to relieve symptoms.
General measures
The first step toward relieving symptoms is getting enough sleep and rest and exercising regularly.
Other measures that have been suggested to help relieve the pain include a low-fat diet and nutritional supplements such as omega-3 fatty acids, flaxseed, magnesium, vitamin B1, vitamin E, and zinc. Moist heat applied to the abdomen may also help.
Drugs
If pain persists, nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen, or mefenamic acid, may help. NSAIDs should be started 24 to 48 hours before a period begins and continued 1 or 2 days after the period begins.
If NSAIDs are ineffective, doctors may recommend also taking birth control pills that contain a progestin and a low dose of estrogen. These pills prevent the ovaries from releasing an egg (ovulation). Women who cannot take estrogen can take birth control pills that contain only a progestin.
Other hormone treatments may also help relieve symptoms. They include danazol (a synthetic male hormone), progestins (such as levonorgestrel, etonogestrel, medroxyprogesterone, or micronized progesterone, taken by mouth), gonadotropin-releasing hormone (GnRH) agonists (such as leuprolide and nafarelin), GnRH antagonists (such as elagolix), and an IUD that releases a progestin. GnRH agonists and antagonists help relieve menstrual cramps due to endometriosis.
Drugs such as gabapentin may also help relieve symptoms. Gabapentin is an antiseizure drug that is sometimes used to reduce pain due to nerve damage.
Other treatments
If women have severe pain that persists despite treatment, doctors may do a procedure that disrupts the nerves to the uterus and thus blocks pain signals. These procedures include the following:
The procedures to disrupt the nerves may be done using a laparoscope. When these nerves are cut, other organs in the pelvis, such as the ureters, are occasionally injured.
Some alternative treatments for menstrual cramps have been suggested but have not been studied well. They include behavioral counseling (such as systematic desensitization and relaxation and pain management training), acupuncture, acupressure, chiropractic therapy, and transcutaneous electrical nerve stimulation (application of a gentle electric current through electrodes placed on the skin). Hypnosis is being studied as treatment.
Key Points
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Usually, menstrual cramps have no identifiable cause (called primary dysmenorrhea).
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Pain is typically crampy or sharp, starts a few days before a menstrual period, and subsides after 2 or 3 days.
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For most women, evaluation includes a pregnancy test, a doctor's examination, and ultrasonography (to check for abnormal structures or growths in the pelvis).
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For primary dysmenorrhea, general measures, such as adequate sleep, regular exercise, heat, and a low-fat diet, may help relieve symptoms.
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NSAIDs or an NSAID plus low-dose birth control pills may help relieve the pain.
