PIP: Uterine perforation is known to be associated with IUD use. Usually the perforation occurs upon insertion, but the IUD can become embedded in the uterus and later be forced through the wall by uterine contractions. On occasion, IUDs have been noted in abdominal viscera, most often the sigmoid colon. Recently, a 20-year-old black woman was encountered whose Copper-7 IUD had perforated her appendix and had caused chronic appendicitis during pregnancy. The woman had had 3 live-born children and 1 spontaneous abortion. The Copper-7 had been inserted 6 months previously without apparent difficulty. At 21 weeks' gestation, the patient developed right lower abdominal pain radiating to the right buttock. She had no other gastrointestinal complaints, was afebrile, and exhibited no abnormal physical findings to explain her symptoms. Urine cultures were negative. 12 weeks later, the patient developed nausea, vomiting, anorexia, and constipation. She was again afebrile. After spontaneous labor at 40 weeks, the patient was delivered of a normal male infant. Following spontaneous expulsion of the placenta, the uterus was manually explored, and no IUD was found. The patient desired postpartum tubal ligation. An x-ray film of the abdomen revealed a Copper-7 IUD in the right lower quadrant at the level of the iliac crest. During the operation, it was noted that the IUD had apparently perforated the uterus 1 centimeter below the right uterotubal junction. The strings were in the myometrium, but the body of the IUD had passed transversely through the lumen of the appendix and remained embedded in it. The IUD may have induced inflammation in an otherwise normal appendix, and this seems most likely particularly because copper-containing IUDs are prone to cause irritation and adhesion formation.