Table 1.
Parameter estimates for the risks of bacterial infection in untreated preterm and term deliveries. Values are means (95% confidence intervals) unless stated otherwise
| Parameter | Preterm deliveries | Term deliveries | Overall mean |
|---|---|---|---|
| Risk of transmission of GBS | |||
| Maternal colonisation (%) | 23.8 (17.2 to 31.4) | 11.1 (8.3 to 14.8) | 12.2 (9.0 to 15.9) |
| Baby colonisation given maternal colonisation (%) | 36.6 (28.4 to 45.9) | 31.5 (24.1 to 40.0) | 32.4 (24.7 to 40.8) |
| Early onset GBS given baby colonisation (%) | 2.2 (1.5 to 3.2) | 1.1 (0.7 to 1.6) | 1.3 (0.9 to 1.8) |
| Risk of infection in baby per 1000 live births | |||
| Early onset GBS | 1.84 (1.53 to 2.19) | 0.38 (0.33 to 0.42) | 0.48 (0.44 to 0.53) |
| Early onset infection other than GBS | 6.97 (5.19 to 9.01) | 0.50 (0.36 to 0.65) | 0.97 (0.81 to 1.14) |
| Late onset GBS | 1.51 (1.20 to 1.84) | 0.15 (0.11 to 0.17) | 0.25 (0.21 to 0.28) |
| Proportion of all deliveries occurring preterm or at term | |||
| All deliveries | 7.3% | 92.7% | — |
| Early onset GBS | 27.9% | 72.1% | — |
| All early onset infections | 45.0% | 55.0% | — |
GBS=group B streptococcal infection.