Pelvic Inflammatory Disease

Overview and Definition
Causes and Risk Factors
Symptoms
Diagnosis
Medical Treatment
Surgical Treatment
Natural and Supportive Care
Complications
Fertility Impact
Fitz-Hugh-Curtis Syndrome
Prognosis
Key Research Papers
Connections
Featured Videos

Overview and Definition

Pelvic inflammatory disease (PID) is an infection of the female upper reproductive tract — the uterus (endometritis), fallopian tubes (salpingitis), ovaries (oophoritis), and the surrounding pelvic peritoneum. It occurs when bacteria, most often sexually transmitted, ascend from the vagina or cervix into structures that are normally sterile. PID is one of the most serious complications of sexually transmitted infections (STIs) and is a leading preventable cause of tubal-factor infertility, ectopic pregnancy, and chronic pelvic pain in reproductive-age women.

The Centers for Disease Control and Prevention (CDC) estimates that more than 1 million women in the United States experience an episode of PID each year. The true incidence is higher because many cases are subclinical — producing no or minimal symptoms — yet still cause progressive tubal scarring. Prompt diagnosis and treatment are critical; each PID episode approximately doubles the risk of subsequent tubal factor infertility.

Causes and Risk Factors

PID is polymicrobial in most cases. The initial pathogens that disrupt the cervical mucus barrier are nearly always sexually transmitted:

Neisseria gonorrhoeae — gram-negative diplococcus; causes a more acute, purulent PID with higher fever and greater tubal destruction than chlamydial PID.
Chlamydia trachomatis — obligate intracellular bacterium; frequently produces subclinical or "silent" PID; responsible for the majority of chlamydial-attributable tubal infertility.
Anaerobes and facultative bacteria — once the mucus barrier is breached, vaginal flora including Bacteroides, Prevotella, Gardnerella vaginalis, Streptococcus agalactiae, and gram-negative enteric organisms co-ascend and amplify tissue damage.
Mycoplasma genitalium — an emerging cause increasingly linked to treatment-refractory PID; resistant to standard azithromycin regimens.

Risk Factors

Age under 25 (highest risk group; cervical ectopy and less protective immune priming)
Multiple or new sexual partners
Prior PID episode
Bacterial vaginosis (disrupts protective lactobacillus-dominant flora)
Intrauterine device (IUD) insertion — risk window is the 21 days immediately after placement, not ongoing use
Unprotected sexual intercourse
Douching (disrupts vaginal pH and flora)
Recent uterine instrumentation (endometrial biopsy, hysteroscopy, dilation and curettage)

Symptoms

Clinical presentation ranges from asymptomatic to life-threatening tubo-ovarian abscess (TOA). Classic findings include:

Lower abdominal or pelvic pain — the most common symptom; typically bilateral, dull to crampy, often worsening during or after menses
Abnormal vaginal discharge — mucopurulent or purulent; may be odorous
Abnormal uterine bleeding — intermenstrual or post-coital spotting
Dyspareunia — deep pelvic pain with intercourse
Fever — temperature above 38.3°C (101°F) in more severe cases; often absent in mild or subclinical PID
Nausea and vomiting — associated with more severe infection or peritoneal involvement
Dysuria — urethral involvement or periurethral inflammation
Right upper quadrant pain — raises suspicion for Fitz-Hugh-Curtis syndrome (perihepatitis; see below)

Diagnosis

The CDC recommends a low threshold for empiric PID treatment because the consequences of untreated or delayed treatment (infertility, chronic pain, ectopic pregnancy) outweigh the risks of unnecessary antibiotics. Diagnosis is clinical.

CDC Minimum Diagnostic Criteria (at least one must be present in a sexually active woman with no other explanation):

Cervical motion tenderness (CMT) — pain when the cervix is moved laterally on bimanual exam; sometimes called "chandelier sign" in severe cases
Uterine tenderness
Adnexal tenderness

Additional Criteria Increasing Diagnostic Specificity:

Oral temperature above 38.3°C (101°F)
Mucopurulent cervical or vaginal discharge on speculum exam
White blood cells on saline microscopy of vaginal secretions
Elevated ESR or C-reactive protein
Laboratory confirmation of N. gonorrhoeae or C. trachomatis cervical infection

Imaging

Transvaginal ultrasound (TVUS) — first-line imaging; identifies tubo-ovarian abscess (thickened, fluid-filled tubes; complex adnexal mass), free pelvic fluid
MRI — superior for soft-tissue characterization when TOA is suspected but ultrasound is equivocal
Laparoscopy — definitive diagnostic standard (direct visualization of inflamed, erythematous fallopian tubes with purulent exudate); reserved for diagnostic uncertainty or treatment failure

Medical Treatment

Treatment should be initiated promptly upon clinical suspicion. The goal is to cover the full spectrum of likely pathogens including gonorrhea, chlamydia, and anaerobes.

Outpatient Regimen (CDC 2021 Guidelines — Preferred)

Ceftriaxone 500 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 14 days WITH metronidazole 500 mg orally twice daily for 14 days
Ceftriaxone provides gonorrhea coverage; doxycycline covers chlamydia; metronidazole extends anaerobic coverage and treats concurrent BV

Alternative Outpatient Regimen

Cefoxitin 2 g IM single dose plus probenecid 1 g orally, PLUS doxycycline 100 mg twice daily for 14 days WITH metronidazole 500 mg twice daily for 14 days

Inpatient (IV) Regimen — Indications for Hospitalization

Hospitalization is recommended when: surgical emergency cannot be excluded; TOA is present; severe illness, nausea, vomiting, or high fever; outpatient treatment failed or cannot be tolerated; pregnancy.

Cefoxitin 2 g IV every 6 hours PLUS doxycycline 100 mg orally or IV every 12 hours — transition to oral doxycycline 100 mg twice daily after 24–48 hours of clinical improvement; complete 14-day total course
Clindamycin 900 mg IV every 8 hours PLUS gentamicin loading dose IV or IM (2 mg/kg), then 1.5 mg/kg every 8 hours (or single daily dosing) — alternative for penicillin-allergic patients

Partner Treatment

All sexual partners within the preceding 60 days must be evaluated and treated empirically for gonorrhea and chlamydia regardless of test results. Expedited partner therapy (EPT) is legal and recommended in most US states when the partner cannot attend in person.

Mycoplasma genitalium

If M. genitalium is identified and the standard regimen fails, moxifloxacin 400 mg daily for 14 days is the preferred salvage therapy. Resistance-guided treatment is increasingly recommended where testing is available.

Surgical Treatment

Tubo-ovarian abscess (TOA) drainage — most TOAs respond to IV antibiotics alone; those ≥3 cm or failing 48–72 hours of medical therapy require drainage, typically via ultrasound-guided transvaginal or transabdominal aspiration
Laparoscopic drainage or salpingectomy — indicated when drainage is not possible percutaneously, when the abscess has ruptured (surgical emergency), or when a unilateral TOA is removed in a woman who has completed childbearing
Laparotomy — rarely needed; reserved for ruptured TOA with hemodynamic instability or when laparoscopic access is not feasible

Natural and Supportive Care

Supportive measures complement but do not replace antibiotic therapy. PID is a bacterial infection requiring systemic antibiotics — delay seeking care can result in permanent tubal damage.

Rest — pelvic rest (no intercourse) during and for 2 weeks after completing treatment; sexual activity before completing the full course risks re-exposure and treatment failure
Pain management — NSAIDs (ibuprofen 400–600 mg every 6 hours with food) reduce inflammation and dysmenorrhea-type cramping; acetaminophen for patients with GI intolerance
Hydration and nutrition — fever and reduced intake increase dehydration risk; anti-inflammatory dietary patterns (Mediterranean-style, rich in omega-3 fatty acids) support immune recovery
Probiotics — Lactobacillus rhamnosus and L. reuteri supplementation during and after antibiotic therapy may help restore vaginal and gut microbiome balance disrupted by broad-spectrum antibiotics; evidence is emerging rather than definitive
Heat therapy — low-level heat pads reduce pelvic cramping and muscle spasm during recovery
Avoid douching — permanently; douching disrupts the protective vaginal flora that guards against ascending infection
Smoking cessation — smoking impairs cervical immune defenses and increases STI susceptibility
Barrier contraception — consistent condom use is the only proven behavioral intervention that reduces PID incidence by reducing STI transmission

Complications

Tubo-ovarian abscess (TOA) — occurs in 15–30% of hospitalized PID cases; can rupture causing life-threatening peritonitis and sepsis
Ectopic pregnancy — tubal scarring from PID increases the risk of ectopic implantation 6–10-fold after a single episode; risk increases with each subsequent PID episode
Tubal factor infertility — approximately 11% of women are infertile after one PID episode, 23% after two, and more than 54% after three or more episodes
Chronic pelvic pain — affects 20–30% of women after PID; caused by adhesions, hydrosalpinx, and central sensitization; can be debilitating
Perihepatitis (Fitz-Hugh-Curtis syndrome) — perihepatic inflammation causing pleuritic right upper quadrant pain, sometimes mimicking cholecystitis or pleuritis
Recurrent PID — 20–25% of women have a second episode, substantially increasing long-term complication risk
Increased ovarian cancer risk — epidemiological data suggest a modest increased risk, possibly related to chronic inflammation

Fertility Impact

PID is the most common preventable cause of tubal-factor infertility in the developed world. The mechanism is inflammation-driven tubal damage: salpingitis triggers an exuberant repair response that deposits fibrin and collagen, causing peritubal adhesions, intraluminal synechiae, and loss of the ciliated epithelium that propels the oocyte toward the uterus.

Hydrosalpinx — fluid-filled, distally obstructed fallopian tube; reduces IVF live-birth rates by approximately 50% when present; salpingectomy before IVF restores rates to baseline
Subclinical PID — women who never received a PID diagnosis (because infection was mild) account for a substantial proportion of unexplained tubal infertility; chlamydia serology (IgG antibody to chlamydia heat-shock protein 60) is a surrogate marker
IVF outcomes — tubal factor infertility is among the best IVF indications with live-birth rates approaching those of unexplained infertility when hydrosalpinx is surgically addressed
Prevention — annual C. trachomatis and N. gonorrhoeae screening in sexually active women under 25 is the most evidence-based intervention to prevent PID-attributable infertility; the US Preventive Services Task Force (USPSTF) gives this a Grade B recommendation

Fitz-Hugh-Curtis Syndrome

Fitz-Hugh-Curtis syndrome is a rare complication of PID — specifically a perihepatitis — in which infection spreads from the pelvis along the right paracolic gutter to inflame the liver capsule (Glisson's capsule) and the adjacent anterior parietal peritoneum. It occurs in 4–14% of PID cases.

Mechanism — most often associated with C. trachomatis; organisms or inflammatory mediators travel along the right paracolic gutter to the perihepatic space
Symptoms — sharp, pleuritic right upper quadrant pain, often severe enough to dominate the clinical picture and overshadow pelvic symptoms; can mimic acute cholecystitis, right-sided pleuritis, or pulmonary embolism
Diagnosis — clinical in the context of PID diagnosis; laparoscopy reveals the pathognomonic "violin string" adhesions between the anterior liver capsule and the parietal peritoneum
Treatment — treated with the same antibiotic regimen as PID; adhesions rarely require surgical lysis unless causing chronic pain
Prognosis — generally resolves with appropriate antibiotic therapy; chronic violin-string adhesions can cause persistent right upper quadrant pain in a minority of patients

Prognosis

Prognosis is strongly related to promptness of diagnosis and treatment. Women who receive antibiotics within the first 3 days of symptom onset have significantly lower rates of infertility and chronic pelvic pain compared to those treated later. Key prognostic points:

Single episode of mild-to-moderate PID treated promptly — most women recover fully without long-term sequelae
TOA — responds to IV antibiotics in 75–90% of cases when <9 cm; surgical drainage is needed in 15–30%
Recurrent PID — each episode multiplicatively increases infertility risk; preventing recurrence through STI screening, partner treatment, and safe sex is paramount
Subclinical PID — because it goes untreated, it may cause the same or greater tubal damage as symptomatic PID before being discovered during infertility workup

Key Research Papers

Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1–187. PMID 34292926.
Wiesenfeld HC, Hillier SL, Meyn LA, Amortegui AJ, Sweet RL. Subclinical Pelvic Inflammatory Disease and Infertility. Obstetrics & Gynecology. 2012;120(1):37–43. PMID 22678035.
Westrom L, Joesoef R, Reynolds G, Hagdu A, Thompson SE. Pelvic Inflammatory Disease and Fertility: A Cohort Study of 1,844 Women with Laparoscopically Verified Disease and 657 Control Women with Normal Laparoscopic Results. Sexually Transmitted Diseases. 1992;19(4):185–192. PMID 1590229.
Haggerty CL, Hillier SL, Bass DC, Ness RB; PID Evaluation and Clinical Health (PEACH) Study Investigators. Bacterial Vaginosis and Anaerobic Bacteria Are Associated with Endometritis. Clinical Infectious Diseases. 2004;39(7):990–995. PMID 15472855.
Ness RB, Soper DE, Holley RL, et al. Effectiveness of Inpatient and Outpatient Treatment Strategies for Women with Pelvic Inflammatory Disease: Results from the Pelvic Inflammatory Disease Evaluation and Clinical Health (PEACH) Randomized Trial. American Journal of Obstetrics & Gynecology. 2002;186(5):929–937. PMID 12015517.
Ross JDC, Gupta S, Bhatt N, et al. Mycoplasma genitalium in Women: Current Knowledge and Research Gaps. BMJ. 2021;372:n3217. PMID 33468518.
Hoenderboom BM, van Benthem BHB, van Bergen JEAM, et al. Relation Between Chlamydia trachomatis Infection and Pelvic Inflammatory Disease, Ectopic Pregnancy and Tubal Factor Infertility in a Dutch Cohort of Women Previously Tested for Chlamydia in a Chlamydia Screening Trial. Sexually Transmitted Infections. 2019;95(4):300–305. PMID 30655338.
Stacey CM, Munday PE, Taylor-Robinson D, et al. A Longitudinal Study of Pelvic Inflammatory Disease. British Journal of Obstetrics and Gynaecology. 1992;99(12):994–999. PMID 1477058.
Paavonen J, Westrom L, Eschenbach D. Pelvic Inflammatory Disease. In: Holmes KK, Sparling PF, Mardh PA, et al, eds. Sexually Transmitted Diseases. 4th ed. McGraw-Hill; 2008:1017–1050. PMID 20443913.
Brunham RC, Gottlieb SL, Paavonen J. Pelvic Inflammatory Disease. New England Journal of Medicine. 2015;372(21):2039–2048. PMID 25992748.
Curry A, Williams T, Penny ML. Pelvic Inflammatory Disease: Diagnosis, Management, and Prevention. American Family Physician. 2019;100(6):357–364. PMID 31524362.
Scholes D, Stergachis A, Heidrich FE, Andrilla H, Holmes KK, Stamm WE. Prevention of Pelvic Inflammatory Disease by Screening for Cervical Chlamydial Infection. New England Journal of Medicine. 1996;334(21):1362–1366. PMID 8614421.

PubMed Topic Searches

Back to Table of Contents

Connections