pelvic inflammatory disease (PID), infection of the female reproductive organs, usually resulting from infection with the bacteria that cause chlamydia or gonorrhea. The infection typically first affects the cervical area, then spreads to the uterus, fallopian tubes, ovaries, and abdomen. Symptoms may be absent but usually include pelvic pain and vaginal discharge. PID can cause abscesses and scarring in the fallopian tubes that can block fertilization or interrupt the egg's progress, resulting in ectopic (tubal) pregnancy and loss of the fetus. Over 1 million women are diagnosed with PID each year in the United States; 100,000 typically become infertile.

nonsteroidal anti-inflammatory drug, a drug that suppresses inflammation in a manner similar to steroids, but without the side effects of steroids; commonly referred to by the acronym NSAID. Also effective in alleviating pain and fever, NSAIDs are commonly used to treat the symptoms of arthritis, gout, bursitis, painful menstruation, and headache. They act by inhibiting the synthesis of prostaglandins, leukotrienes, and other compounds that are involved in the inflammatory process.

Aspirin is technically an NSAID, but the term is often used to refer to nonaspirin products. The first nonaspirin NSAIDs were introduced in 1964. Common NSAID products include diclofenac (Cataflam, Voltaren), piroxicam (Feldene), and indomethacin (Indocin). acetaminophen, ibuprofen, naproxen, and ketoprofen are available as over-the-counter drugs in the United States. The cox-2 inhibitors, such as celecoxib (Celebrex), selectively inhibit clooxygenase-2 (cox-2), an enzyme that causes pain and inflammation in arthritic joints, but do not interfere with cox-1, which protects the stomach and intestinal lining from ulceration. Very common drugs, NSAIDs are taken daily by an estimated 3 million Americans.

Although they are often considered easier to tolerate than aspirin, and most do not have as strong an anticlotting effect as aspirin, NSAIDS can have serious side effects, particularly gastrointestinal ulcers and upper gastrointestinal tract bleeding and perforation in those who take the drugs on a regular basis. NSAID-related gastropathy results in more than 2,000 deaths in the United States each year.

Acute inflammation of the pelvic cavity in women, caused by bacterial infection (usually gonorrhea or chlamydia) of the reproductive system. Usually a sexually transmitted disease, it occurs mainly in sexually active women under age 25, more often in those using intrauterine devices (IUDs). PID can resemble gonorrhea, with abdominal and lower pelvic pain, chills, nausea, fever, and thick, foul-smelling vaginal discharge. Fallopian tube scarring can cause infertility and ectopic pregnancy. Treatment requires antibiotics, bed rest, pain medication, and sexual abstinence until the infection disappears. Sexual partners must also be treated to prevent reinfection.

Learn more about pelvic inflammatory disease (PID) with a free trial on Britannica.com.