Pelvic Inflammatory Disease (PID)

How PID develops

Bacteria living in the vagina and cervix travel upward through the cervix into the uterus, fallopian tubes and ovaries. Inflammation of the tubes (salpingitis) can scar and block them. Sometimes an abscess forms around the tube and ovary (tubo-ovarian abscess).

Causes and risk factors

• sexually transmitted infections: chlamydia and gonorrhea are the best-known causes; Mycoplasma genitalium is increasingly recognized
• vaginal bacteria associated with bacterial vaginosis

Risk factors include:

• age under 25 and being sexually active
• multiple partners or a partner with other partners
• previous PID or STI
• not using condoms
• in the first 3 weeks after IUD insertion (risk is low and mostly linked to existing infection)
• procedures that open the cervix, such as abortion or miscarriage management

Symptoms

Symptoms range from mild to severe, and many people have subtle or no symptoms.

• pain or tenderness in the lower belly or pelvis, usually on both sides
• abnormal vaginal discharge, often yellow or green with an unpleasant smell
• pain during sex (deep dyspareunia)
• bleeding between periods or after sex
• painful or more frequent urination
• fever and chills
• nausea and vomiting in more severe cases
• pain in the upper right belly (Fitz-Hugh-Curtis syndrome, from inflammation around the liver)

Diagnosis

There is no single test. The CDC advises a low threshold for diagnosis, because delayed treatment increases complications. Diagnosis is based on:

• pelvic exam: tenderness when the cervix is moved, or tenderness of the uterus or ovaries
• swab tests for chlamydia, gonorrhea and Mycoplasma genitalium
• pregnancy test to rule out ectopic pregnancy
• urine tests and blood tests, including inflammatory markers
• pelvic ultrasound to look for an abscess
• laparoscopy in uncertain or severe cases

A negative swab does not rule out PID.

Treatment

Antibiotics

Treatment starts as soon as PID is suspected. The CDC-recommended outpatient regimen for most people is a single injection of ceftriaxone plus 14 days of doxycycline and metronidazole tablets. Complete the full course even if you feel better.

Hospital treatment

Admission and IV antibiotics are recommended for:

• severe illness, high fever or vomiting
• tubo-ovarian abscess
• pregnancy
• no improvement on oral antibiotics
• when surgical emergencies such as appendicitis cannot be ruled out

Abscesses may need drainage.

Partners and follow-up

• sexual partners from the past 60 days should be tested and treated
• avoid sex until treatment is finished and partners are treated
• recheck within 72 hours to confirm improvement
• retest for chlamydia and gonorrhea about 3 months later
• test for HIV and syphilis

An IUD does not usually need to be removed if PID develops, unless there is no improvement.

Complications

• infertility: risk rises with each episode of PID
• ectopic pregnancy: scarred tubes make it more likely a pregnancy implants in the tube
• chronic pelvic pain
• tubo-ovarian abscess
• recurrent PID
• hydrosalpinx: a blocked, fluid-filled tube

Prevention

• use condoms consistently
• get tested for chlamydia and gonorrhea yearly if you are sexually active and under 25, or older with risk factors
• ensure partners are tested and treated
• seek prompt care for symptoms

Frequently asked questions

What are the symptoms of pelvic inflammatory disease?

Common symptoms are lower belly or pelvic pain, unusual vaginal discharge, pain during sex, bleeding between periods or after sex, painful urination and fever. Symptoms can be mild or absent, so testing is important if you have risk factors.

What causes PID?

PID is most often caused by sexually transmitted bacteria, such as chlamydia and gonorrhea, spreading up from the cervix. Other bacteria from the vagina, including those linked to bacterial vaginosis, can also cause it.

Can PID cause infertility?

Yes. PID can scar the fallopian tubes, making it harder for an egg to reach the uterus and increasing the risk of ectopic pregnancy. The risk rises with each episode and with delayed treatment, which is why prompt antibiotics are important.

How long does PID take to go away?

Most people feel better within a few days of starting antibiotics, and treatment lasts 14 days. Symptoms that do not improve within 72 hours need review. Complete the full course and avoid sex until you and your partners have finished treatment.