Table 2.
Risk factors associated with preterm PROM (at less than 35 weeks) stratified by parity.
| Nulliparous | Multiparous | |||
|---|---|---|---|---|
| Risk Factor | Odds Ratio | 95% Confidence Interval | Odds Ratio | 95% Confidence Interval |
| Cervical length ≤ 25 mm | 9.9 | 3.8–25.9 | 4.2 | 2.0–8.9 |
| Previous preterm birth with preterm PROM | -- | -- | 4.1 | 2.0–8.7 |
| Previous preterm labor with intact membranes | -- | -- | 2.6 | 1.2–5.3 |
| Working during pregnancy | 5.3 | 1.5–18.7 | n.s. | n.s. |
| Medical complications | 4.2 | 1.1–16.0 | n.s. | n.s. |
| FFN (+) | n.s. | n.s. | n.s. | n.s. |
| BV | n.s. | n.s. | n.s. | n.s. |
| FFN (+) and absent BV | n.s. | n.s. | 9.0 | 3.6–22.5 |
| FFN (−) and present BV | n.s. | n.s. | 2.8 | 1.2–6.3 |
FFN = fetal fibronectin; BV = bacterial vaginosis; n.s. = non-significant.
Modified from Mercer et al,82 with permission.
Mercer BM, Goldenberg RL, Meis PJ, Moawad AH, Shellhaas C, Das A et al. The Preterm Prediction Study: prediction of preterm premature rupture of membranes through clinical findings and ancillary testing. The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Am. J. Obstet. Gynecol. 2000;183:738–45.