| Maternal infection after delivery and before discharge | 18% v 20% | 15% (4 to 24) | 33 (19 to 143) |
| Chorioamnionitis | 16% v 26% | 38% (25 to 49) | 11 (8 to 17) |
| Birth within 24 hours | 32% v 40% | 23% (17 to 28) | 12 (9 to 16) |
| Birth within 7 days | 8% v 67% | 12% (8 to 16) | 13 (10 to 19) |
| Neonatal infection, including pneumonia | 11% v 17% | 33% (15 to 48) | 18 (12 to 46) |
| Positive neonatal blood culture | 6.4% v 8.4% | 25% (7 to 40) | 48 (27 to 200) |
| Neonatal oxygenation > 28 days | 8.5% v 11% | 19% (3 to 32) | 48 (27 to 334) |
| Abnormal cerebral ultrasonographic scan before discharge | 5.6% v 9.4% | 18% (1 to 32) | 67 (35 to 1000) |