['This prospective study was undertaken to test the hypothesis that microscopic chronic salpingitis is an etiologic factor in ectopic (tubal) pregnancy with an intrauterine device (IUD).', 'Fifty consecutive patients at a university hospital operated for tubal pregnancy fulfilled strict histological diagnostic criteria for tubal pregnancy. There were no statistically significant differences in prevalence of microscopic findings of chronic inflammation in patients who never used an IUD, had a history of IUD use, or had an IUD in situ at the time of laparotomy. Salpingitis isthmica nodosa was found in four patients (30.8%) without past or present history of IUD use as compared to two patients (5.4%) with past or present history of IUD (P < .05).'] Is microscopic salpingitis an etiologic factor of tubal pregnancy with intrauterine devices?