| Degree of risk | Risk factors | Odds ratio |
| High | Previous ectopic pregnancy | 2.7 to 8.3 |
| Previous tubal surgery | 2.1 to 21 | |
| Tubal pathology | 3.5 to 25 | |
| Sterilization | 5.2 to 19 | |
| IUD | ||
| - Past use | 1.7 | |
| - Current use | 4.2 to 16.4 | |
| - Levonorgestrel IUD | 4.9 | |
| In vitro fertilization in current pregnancy | 4.0 to 9.3 | |
| Moderate | Current use of estrogen/progestin oral contraceptives | 1.7 to 4.5 |
| Previous sexually transmitted infections (gonorrhea, chlamydia) | 2.8 to 3.7 | |
| Previous of pelvic inflammatory disease | 2.5 to 3.4 | |
| In utero DES exposure | 3.7 | |
| Smoking | ||
| - Past smoker | 1.5 to 2.5 | |
| - Current smoker | 1.7 to 3.9 | |
| Previous pelvic/abdominal surgery | 4.0 | |
| Previous spontaneous abortion | 3.0 | |
| Low | Previous medical induced abortion | 2.8 |
| Infertility | 2.1 to 2.7 | |
| Age ≥40 years | 2.9 | |
| Vaginal douching | 1.1 to 3.1 | |
| Age at first intercourse <18 years | 1.6 | |
| Previous appendectomy | 1.6 |