[Risk factors for ectopic pregnancy. Case-control study].

BACKGROUND: To analyze risk factors for ectopic pregnancy in an Italian population. METHODS: A retrospective case-control study has been carried out on 213 cases of ectopic pregnancy and 213 controls. The control subjects were women who delivered spontaneously at the same time and in the same hospital of the cases considered. RESULTS: Smoking more than 10 cigarettes/die doubles the risk of ectopic pregnancy. IUD causes an increased risk in women using this contraceptive method for less than two years. A history of abdominal surgery was associated with about a double risk of ectopic pregnancy. The risk was higher in cases of cesarean section and pelvic surgery. CONCLUSIONS: Abdominal surgery (particularly pelvic surgery and cesarean sections), use of IUD for less than two years and cigarette smoking are the risk factors found to be a cause for ectopic pregnancy in the population studied. It was not possible to evaluate the history of pelvic inflammatory disease because there were not enough data. For this reason it is suggested it will be possible in the future to compile a register data, collecting all the cases of ectopic pregnancy as a part of a prevention campaign.