| CASES (n) | % | CONTROL (n) | % | p-value | |
| Term | 26 | −12.3 | 102 | −51.5 | <0.05 |
| Preterm | 3 | −1.4 | 6 | −3 | NS |
| Twin | 2 | −0.9 | 6 | −3 | NS |
| Abortion | 174 | −82.4 | 77 | −38.8 | <0.001 |
| Ectopic | 3 | −1.4 | 7 | −3.5 | NS |
| Molar | 3 | −1.4 | 0 | 0 | - |
| Total | 211 | 100% | 198 | 100% | 409 |