Etiology of Chronic Pelvic Pain
Potential sources of chronic pelvic pain include the reproductive, genitourinary, and gastrointestinal tracts; the pelvic bones, ligaments, muscles, and fascia. Chronic pelvic pain may result from psychologic disorders or neurologic diseases, both central and peripheral.

Populations at Increased Risk of Chronic Pelvic Pain
Demographic profiles of large surveys suggest that women with chronic pelvic pain are no different from women without chronic pelvic pain in terms of age, race and ethnicity, education, socioeconomic status, or employment status. Women with chronic pelvic pain may be slightly more likely to be separated or divorced. Women with chronic pelvic pain tend to be of reproductive age; however, age does not appear to be a specific risk factor.

Physical and Sexual Abuse
Studies have found that 40-50% of women with chronic pelvic pain have a history of abuse. Whether abuse (physical or sexual) specifically causes chronic pelvic pain is not clear, nor is a mechanism established by which abuse might lead to the development of chronic pelvic pain.

Pelvic Inflammatory Disease
Approximately 18-35% of all women with acute pelvic inflammatory disease (PID) develop chronic pelvic pain. The actual mechanisms by which chronic pelvic pain results from PID are not known, and not all women with reproductive organ damage secondary to acute PID develop chronic pelvic pain. Whether acute PID is treated with outpatient or inpatient regimens does not appear to significantly alter the odds of developing subsequent chronic pelvic pain.

Endometriosis
Although endometriosis may be a direct cause of chronic pelvic pain, it also may indirectly place women at increased risk for chronic pelvic pain. For example, evidence suggests that women with endometriosis have increased episodes and pain severity of urinary calculoses than women without endometriosis. Similar results have been demonstrated for vaginal pain.

Interstitial Cystitis
Women with interstitial cystitis are at significant risk of having chronic pelvic pain. Interstitial cystitis is a chronic inflammatory condition of the bladder. It is clinically characterized by irritative voiding symptoms of urgency and frequency in the absence of objective evidence of another disease that could cause the symptoms.

Irritable Bowel Syndrome
Irritable bowel syndrome appears to be one of the most common disorders associated with chronic pelvic pain. It seems to occur much more commonly in women with chronic pelvic pain than in the general population.

Obstetric History
Pregnancy and childbirth can cause trauma to the musculoskeletal system, especially the pelvis and back, and may lead to chronic pelvic pain. Although few well-designed trials have assessed the relationship, historical risk factors associated with pregnancy and pain include lumbar lordosis, delivery of a large infant, muscle weakness and poor physical conditioning, a difficult delivery, vacuum or forceps delivery, and use of gynecologic stirrups for delivery. Conversely, women who have never been pregnant may have disorders that can cause both infertility and chronic pelvic pain, such as endometriosis, chronic PID, or pelvic adhesive disease.

Past Surgery
A history of abdominopelvic surgery is associated with chronic pelvic pain. Prior cervical surgery for dysplasia may cause cervical stenosis, which has been associated with endometriosis. Additionally, among women without preoperative pelvic pain, 3-9% develop pelvic pain or back pain in the 2 years after hysterectomy. A recent case-control study suggests that cesarean delivery also may be a risk factor for chronic pelvic pain.

Musculoskeletal Disorders
Musculoskeletal disorders as causes of or risk factors for chronic pelvic pain have not been widely discussed in gynecologic publications. They may be more important, however, than generally recognized.

Diagnostic Studies
Up to two thirds of women with chronic pelvic pain do not undergo diagnostic testing, never receive a diagnosis, and are never referred to a specialist for evaluation or treatment.

Diagnostic Imaging
Transvaginal ultrasonography is particularly useful for evaluation of the pelvis. In patients with a pelvic mass, ultrasonography may help identify the origin of the mass as uterine, adnexal, gastrointestinal, or from the bladder. Magnetic resonance imaging or computed tomography may be useful in rare cases when ultrasound findings are abnormal.

Laparoscopy
Chronic pelvic pain is the indication for at least 40% of all gynecologic laparoscopies. Endometriosis and adhesions account for more than 90% of the diagnoses in women with discernible laparoscopic abnormalities, and laparoscopy is indicated in women thought to have either of these conditions. When endometriosis is suspected on the basis of visual findings during laparoscopy, biopsies and histologic confirmation of suspicious areas are important because the visual diagnosis is incorrect in 10-90% of cases. Often, adolescents are excluded from laparoscopic evaluation on the basis of their age, but several series show that endometriosis is as common in adolescents with chronic pelvic pain as in the rest of the population.

Clinical Considerations and Recommendations

Is there evidence to support the following medical approaches to treatment of chronic pelvic pain?

Antidepressants
Tricyclic antidepressants, such as imipramine, amitriptyline, desipramine, and doxepin, have been shown in placebo-controlled studies to improve pain levels and pain tolerance in some, but not all, chronic pain syndromes. It is not clear how effective other antidepressants, such as SSRIs, are in the treatment of chronic pain syndromes.

At this time, evidence is insufficient to substantiate efficacy of antidepressants for the treatment of chronic pelvic pain. Nonetheless, the substantial association of depression with chronic pelvic pain supports the use of antidepressants for the specific treatment of depression.

Local Anesthetic Injection of Trigger Points
Chronic pain syndromes associated with myofascial trigger points have been clinically recognized for quite some time. Observational data on the use of local anesthetic injection of trigger points of the abdominal wall, vagina, and sacrum for relief of chronic pelvic pain have demonstrated a response rate of 68%.

Analgesics
Extensive evidence demonstrates that nonsteroidal antiinflammatory drugs relieve various types of pain. No clinical trials have addressed chronic pelvic pain specifically, but moderate analgesic efficacy, as shown for other types of pain, would be anticipated.

Is there evidence to support the use of hormonal therapy for treatment of chronic \ pelvic pain?

Combined Oral Contraceptives
Oral contraceptives provide significant relief from primary dysmenorrhea. They suppress ovulation, markedly reduce spontaneous uterine activity, stabilize estrogen and progesterone levels, abrogate menstrual increases in prostaglandin levels, and reduce the amount of pain and symptoms associated with menses. These effects also are thought to make oral contraceptives effective in the treatment of other gynecologic pain disorders. Oral contraceptives often are recommended for endometriosis-associated chronic pelvic pain, but there are limited data from clinical trials to support this recommendation.

Gonadotropin-Releasing Hormone Agonists
Gonadotropin-releasing hormone agonists available in the United States are nafarelin, goserelin, and leuprolide. Numerous clinical trials show GnRH agonists are more effective than placebo and as effective as danazol in relieving endometriosis-associated pelvic pain.

Progestins
Clinical trials suggest progestins are effective in the treatment of chronic pelvic pain associated with endometriosis and pelvic congestion syndrome.

What is the evidence for efficacy of proposed nonmedical treatments? Many modalities of treatment other than medications and surgery have been recommended for chronic pelvic pain, including exercise, physical therapy, and dietary modifications. Very few of these treatments have been studied in clinical trials.

Physical Therapy
Observational studies suggest various physical therapy modalities are effective for pain relief. Electrotherapy, fast- and slow-twitch exercises of the striated muscles of the pelvic floor, and manual therapy of myofascial trigger points in the pelvic floor have shown improvement of pain in 65-70% of patients.

Are surgical approaches effective for treatment of chronic pelvic pain? Various surgical treatments aimed primarily at treating endometriosis, including excision or destruction of endometriotic tissue and hysterectomy, have been proposed to relieve chronic pelvic pain. Other surgical approaches also have been considered.

Excision or Destruction of Endometriotic Tissue
It is suggested that conservative surgical treatment of endometriosis results in significant pain relief for 1 year in 45-85% of women.

Hysterectomy
Although based only on observational studies, it appears that at least 75% of women who have a hysterectomy for chronic pelvic pain thought to be caused by gynecologic disease experience pain relief at 1 year of follow-up.

Adhesiolysis
Adhesions are commonly thought to be a potential cause of chronic pelvic pain, and evidence from conscious laparoscopic pain mapping suggests some women have painful adhesions. Observational studies suggest that up to 85% of women improve after adhesiolysis.

Nerve Stimulation
Sacral nerve stimulation is beneficial in the treatment of chronic voiding dysfunction. Its use in women with voiding dysfunction and chronic pelvic pain has suggested potential efficacy for treatment of chronic pelvic pain. Uncontrolled studies of sacral nerve stimulation in women with chronic pelvic pain and no voiding disorder suggest that 60% of women show significant improvement in their pain levels.

Is counseling or psychotherapy effective for treatment of chronic pelvic pain?
Psychosomatic factors appear to have a prominent role in chronic pelvic pain, which suggests that psychiatric or psychologic evaluation and treatment should be routine in women with chronic pelvic pain. Various modes of psychotherapy, including cognitive therapy, operant conditioning, and behavioral modification, appear to be helpful in women with chronic pelvic painbut most of the data are observational or include psychotherapy as part of multidisciplinary treatment.

Are complementary or alternative medicine therapies effective for treating chronic pelvic pain?

Herbal and Nutritional Therapies
Treatment of dysmenorrhea has been studied in clinical trials of magnesium, vitamin B6, vitamin B1, omega-3 fatty acids, and a Japanese herbal combination (Japanese angelica root, peony root, hoelen, atractylodes lancea root, alisma root, cnidium root). Vitamin B1 and magnesium were significantly more effective than a placebo in numerous studies, but data were insufficient to recommend the other therapies for dysmenorrhea.

Magnetic Field Therapy
The application of magnets to abdominal trigger points appears to improve disability and reduce pain when compared with placebo magnets. However, only one clinical trial evaluated the use of magnet therapy, and it had significant methodologic flaws.

Acupuncture Clinical trials evaluating the efficacy of acupuncture, acupressure, and transcutaneous nerve stimulation therapies have been performed only for primary dysmenorrhea, not for nonmenstrual pelvic pain. All 3 modalities are better than placebo in the treatment of dysmenorrhea.

References available upon request.

This excerpt from ACOG's Practice Bulletin, Clinical Management Guidelines for Obstetrician-Gynecologists Number 51, is provided for your information. It is not medical advice and should not be relied upon as a substitute for visiting your doctor.