Highly increased risk (OR = 4–40) | Moderately increased risk (OR = 2–20) |
 Previous tubal surgery |  Infertility |
 Documented tubal pathology |  Previous genital infections |
 History of EP |  Multiple sexual partners |
 In-utero exposure to DES |  |
 | |
Minimally increased risk (OR = 1-4) | Other risk factors |
 Previous pelvic/abdominal surgery |  Age (> 35–40 years) |
 Cigarette smoking |  Assisted reproductive technologies |
 Vaginal douching |  Anatomical uterine abnormality |
 Early age at first intercourse |  Non-Caucasian |
 Prior spontaneous or medically induced abortion |