Table 1.
Selected risk factors and their relative risks for chorioamnionitis,
| Risk factor | Relative risk | Reference(s) |
|---|---|---|
| Prolonged membrane rupture (including PPROM) | ||
| ≥ 12 hours | 5.8 | 13 |
| > 18 hours | 6.9 | 15 |
| Prolonged labor | ||
| Second stage > 2 hours | 3.7 | 15 |
| Active labor > 12 hours | 4.0 | 14 |
| Multiple digital exams with membrane rupture | ||
| ≥ 3 exams | 2 to 5 | 13–14 |
| Nulliparity | 1.8 | 14 |
| Group B streptococcus colonization | 1.7 to 7.2 | 14, 16, 19 |
| Bacterial vaginosis | 1.7 | 17 |
| Alcohol and tobacco use | 7.9 | 15 |
| Meconium-stained amniotic fluid | 1.4–2.3 | 7, 14 |
| Internal monitoring | 2.0 | 13 |
| Epidural anesthesia | 4.1 | 15 |