[Risk factors for ectopic pregnancy. Results of a case control study in the Rhone-Alpes region]

A case-control study was conducted in 14 Rhône-Alpes area (France) maternity hospitals to evaluate the role of several risk factors, particularly infectious factors, in ectopic pregnancy. A total of 624 cases and 1,247 controls were compared for sociodemographic characteristics, cigarette smoking, sexual reproductive and surgical histories, and condition of conception. Different risk factors were found to be associated with an increased risk of ectopic pregnancy: pelvic inflammatory disease confirmed by celioscopy (OR = 3.8, 95%, CI = 2.1-6.9), Chlamydia trachomatis seropositivity (OR = 4.6, 95%, CI = 3.4-6.3), cigarette smoking at the time of conception with a dose-related effect (OR = 1.6 to 2.6), prior tubal surgery (OR = 1.8, 95%, CI = 1.0-3.1), prior uterus, surgery (OR = 3.2, 95%, CI = 1.4-7.1), prior ectopic pregnancy (OR = 6.4, 95%, CI = 3.6-11.3), induced conception cycle by clomiphene citrate (OR = 4.5, 95%, CI = 1.7-12.0), endometriosis (OR = 6.7, 95%, CI = 2.6-17.4) and maternal age, with a strong relation after the age of 35. These findings confirm the major role of pelvic inflammatory disease which could explain fifty percent of the cases and the one of cigarette smoking at the time of conception which could explain twenty percent of the cases.