Prevalence

Given the lack of established definitions for CPP, prevalence estimates vary. The prevalence of CPP was estimated to range from 4 percent to 43 percent in a systematic review of worldwide prevalence including 18 studies of variable quality.⁷ Across 3 studies with representative samples, the prevalence range of CPP was 2 percent to 29 percent.⁷ One of these studies, conducted in Australia, estimated a point prevalence of 3.8 percent in women aged 15 to 73, a prevalence comparable with that of asthma (3.7 percent) and chronic back pain (4.1 percent).⁸

Health Impact

CPP in women is common and difficult to treat.^4,9 The diagnosis of CPP is often delayed, leading to frustration and dissatisfaction for both the woman and her clinician. Treatments for CPP may often yield unsatisfactory results.¹⁰

CPP, both cyclic and noncyclic, accounts for about 1 in 10 outpatient gynecology visits and is the indication for an estimated 15 percent to 40 percent of laparoscopies and 12 percent of hysterectomies in the United States.^9,11 In a Gallup poll of 5,325 women in the United States, 557 indicated they had CPP within the previous month. Over half of these respondents noted that CPP interfered with mood and energy to complete daily activities and 15 percent reported work absenteeism.¹⁰

An estimated $1.2 billion per year is spent on outpatient management of CPP in the United States (adjusted for inflation from $880 million in 1996). In addition, the total indirect cost due to time lost from work is estimated to be $760 million per year (adjusted for inflation from $555 million in 1996).¹⁰ CPP carries a significant quality of life burden in terms of sexual functioning, depression, fatigue, and physical limitations and disability associated with pain.¹⁰

An individual woman's experience of CPP is inevitably affected by a combination of physical, psychological and social factors, and the condition's impact on quality of life can be substantial. Women with CPP tend to report lower general physical health scores than women without pain.^12-15 Women with CPP describe loss, social isolation, and effects on relationships and have a high incidence of comorbidity, sleep disturbance, and fatigue. A community based study found that 41 percent of women with CPP had not seen a health care provider in the previous year,^12,13 suggesting that most women are coping outside the system.

Etiology

The causes of CPP are poorly understood, and diagnosis of an underlying cause is complicated because the pain is rarely associated with a single underlying disorder or contributing factor;⁴ Howard outlined more than 60 diseases and conditions associated with CPP.⁴ CPP is frequently reported in the presence of both gynecologic and nongynecologic diagnoses, including endometriosis, intra-abdominal adhesions, myofascial pain disorders, irritable bowel syndrome (IBS) and interstitial cystitis (IC)/painful bladder syndrome (PBS).^1,5,16-27

Empirically established relationships among putative causes of CPP and CPP are variable. For example, adhesions are often thought to be a frequent cause of pelvic pain; in fact there is little difference in the prevalence of adhesions found in women with and without CPP.^22,24 It is thus unknown whether associated factors and conditions are etiologic (causal) in nature or are comorbidities with distinct etiologies from the CPP. Regardless, from the patient perspective, the presence of one or more conditions may coalesce in a common presentation of pain. For the purposes of treatment and research in this area, identifying clinical comorbidities that are in fact associated with a CPP diagnosis may affect clinical practice by guiding decisions about diagnostic and treatment processes.

Comorbidities

A number of conditions are reported along with CPP in the literature; however, understanding the prevalence of comorbidities and their contributions to overall pain is complex. Some research suggests that multiple comorbidities may intensify pain and dysfunction.²⁸ Research investigating comorbidities may seek to delineate more clearly the population studied or to ensure that individuals with multiple pain sites are categorized appropriately (e.g., CPP compared with fibromyalgia). Comorbidity research in CPP may also strive to define conditions that may be secondary endpoints, such as IBS, or to recognize conditions that may be important contributors to pain, such as depression. Comorbidity research is also complicated by the lack of standardized definitions or consistent diagnostic criteria for many conditions.

Comorbidities frequently associated with CPP include IBS, with studies reporting IBS prevalence of 35 to 65 percent in women with CPP.^29-31 As many as 85 percent of women with CPP meet some criteria for IC or PBS.^11,32 Prevalence estimates for endometriosis in women with CPP range from 33 to 70 percent.^33,34 Depression and sleep disorders are also commonly reported among women with CPP.³⁵

CPP has also been suggested to be associated with numerous general, gynecologic, and obstetric factors including abuse (childhood physical or sexual abuse, lifetime sexual abuse); psychological morbidity (anxiety, depression, sleep disorders, hysteria, somatization, drug abuse, alcohol abuse); obstetric history (previous miscarriage, cesarean birth); gynecologic history (longer menstrual flow, presence of endometriosis, clinically suspected pelvic inflammatory disease, pelvic adhesions).⁷ Anxiety, depression, sexual problems, and sleep disorders may also be common in CPP in women.^7,35,36

The relationships between CPP and sexual or physical abuse are complex. Many studies reporting such associations are cross-sectional and performed in settings of secondary and tertiary care.^37,38 In these selected populations, some studies reported that women with chronic pain in general are more likely to report physical or sexual abuse as children than pain-free women. Those who experienced CPP were more likely to report past sexual abuse than women with another type of chronic pain;^39-43child sexual abuse may be a correlate of continuing abuse and concomitant development of depression, anxiety or somatization, which then predispose the individual to the development or presentation of CPP.^39,40,44

Evaluation of CPP

Evaluation of CPP and definitive diagnosis of the cause are complex. Indeed, one retrospective study from the United Kingdom found that more than 25 percent of women with CPP never received a definitive diagnosis after nearly 4 years of follow-up.^8,45 A thorough patient evaluation including pain history and pain mapping is a critical step in determining the potential etiology and an initial therapeutic course and in establishing a rapport between the clinician and patient.^46-48 The experience of pain will inevitably be affected by physical, psychological and social factors. Thus CPP may also be viewed from a biopsychosocial perspective, which considers the contributions of organic pathology, patient beliefs, coping skills, social interactions, and overlapping conditions to the experience of pain.⁴⁹

Surgical approaches to evaluation include laparoscopy. CPP is the reported indication for at least 40 percent of diagnostic and therapeutic laparoscopic procedures in the United States.^4,50Endometriosis, pelvic adhesions, chronic pelvic inflammatory disease, and ovarian cysts are the diagnoses most commonly made by laparoscopy in patients with a preoperative diagnosis of CPP;^4,7,22 however, at diagnostic laparoscopy, a substantial proportion of women with CPP (24 to 55 percent) have no obvious pathological cause for their pain.^22,51 Even when pathology is found, it may not be causing the CPP, and a definitive cause and diagnosis are often not determined.

Interventions

Empirical treatment, or treatment based on clinician experience and observation as the basis for decision-making, rather than systematic logic or solid evidence, for CPP as a symptom is increasingly recommended as standard initial management.^1,52,53 For example, current guidelines from the American College of Obstetricians and Gynecologists include an empirical trial of gonadotropin releasing hormone (GnRH) agonists for women who are suspected to have CPP and endometriosis and do not desire a definitive diagnosis or wish to defer surgical investigation.¹

A range of therapeutic interventions are used in clinical practice. Pharmacologic therapies include narcotic and nonnarcotic analgesics; antineuropathics; serotonin reuptake inhibitors; botulinum A toxin injections; and hormonal therapies such as cyclic combined hormonal contraceptives, continuous combined hormonal contraceptives, progestogens, GnRH, and aromatase inhibitors.¹ Surgical interventions, which may be performed laparoscopically or in open surgical procedures, include hysterectomy (with or without oophorectomy or salpingo-oophorectomy), utero-sacral nerve ablation, presacral neurectomy, lysis of adhesions, and uterosacral ligament resection. CPP (both cyclic and noncyclic) has been listed as the principal preoperative indication for 10 percent to 18 percent of hysterectomies in the United States.^9,54-61

Other therapeutic interventions used in clinical practice include behavioral therapies such as biofeedback, psychotherapy, cognitive behavioral therapy, and support groups. Among allied health approaches, physical therapy, dietary modification, and exercise therapy have been used to treat CPP. Complementary and alternative modalities include hypnosis, herbal medicine, massage, acupuncture, meditation, and stress-reduction approaches. A recent Cochrane review of 14 RCTs of interventions for CPP (excluding studies of patients with pain “known to be caused by” endometriosis, primary dysmenorrhea [period pain with onset at menarche], pain due to active chronic pelvic inflammatory disease, or irritable bowel syndrome)² noted that the range of effective therapies for CPP is limited and that recommendations for their use are based largely on single studies. A recent narrative review⁶² similarly concluded that few treatment modalities have demonstrated benefit for relieving CPP symptoms.

Summary

CPP is a common and broadly defined condition. Multiple interventions are used empirically in clinical practice to manage potential etiologies and to treat pain symptoms. The condition is frequently complicated by comorbidities, including depression, anxiety, IBS, and idiopathic pain disorders, and treatment must target symptoms across a spectrum of conditions. Existing literature cites a range of treatment options for women with CPP, many of which have not been tested in rigorous studies.

Scope of the Report

Evidence reviews of therapeutics seek to identify and systematically summarize objective information about the evidence related to factors including the:

• Effectiveness of specific, well-defined treatments
• Relative benefit of one treatment over another
• Common side effects and serious risks of a treatment.

We focused this review on therapies for women over the age of 18 with noncyclic or mixed cyclic/noncyclic chronic pelvic pain. Throughout this review, CPP refers to noncyclic or mixed cyclic/noncyclic pelvic pain unless otherwise noted.

Key Questions

We have synthesized evidence in the published literature to address these Key Questions (KQs):

KQ1.

Among women who have been diagnosed with noncyclic/mixed cyclic and noncyclic CPP, what is the prevalence of the following comorbidities: dysmenorrhea, major depressive disorder, anxiety disorder, temporomandibular joint pain disorder, fibromyalgia, IBS, IC/PBS, complex regional pain syndrome, vulvodynia, functional abdominal pain syndrome, low back pain, headache, and sexual dysfunction?

KQ2.

Among women with noncyclic/mixed cyclic and noncyclic CPP, what is the effect of surgical interventions on pain status, functional status, satisfaction with care, and quality of life?

KQ3.

What is the evidence that surgical outcomes differ if the etiology of noncyclic/mixed cyclic and noncyclic CPP is identified after surgery?

KQ4.

Among women with noncyclic/mixed cyclic and noncyclic CPP, what is the effect of nonsurgical interventions on pain status, functional status, satisfaction with care, quality of life, and harms?

KQ5.

What is the evidence for choosing one intervention over another to treat persistent or recurrent noncyclic/mixed cyclic and noncyclic CPP after an initial intervention fails to achieve target outcome(s)?