Table 5.
Analysis of risk of bias across studies comparing water immersion for labour and waterbirth to standard care
| Outcome | K | Begg’s test rank correlation S-statistic (P) |
Egger’s regression Intercept (P) |
Trim-and-fill direction of bias* OR (95% CI) |
| Amniotomy | 5 | 4 (0.164) | 5.04 (0.129) | Standard care 0.43 (0.34 to 0.53) |
| Induction | 3 | −3 (0.059) | −10 (0.238) | – |
| Augmentation | 3 | 3 (0.59) | 28.96 (0.057) | Standard care 0.12 (0.09 to 0.16) |
| Opioid | 8 | −2 (0.402) | 2.13 (0.197) | Standard care 0.17 (0.15 to 0.19) |
| Epidural | 7 | −9 (0.088) | −4.51 (0.039) | Immersion 0.67 (0.54 to 0.83) |
| Caesarean | 8 | −2 (0.402) | −0.74 (0.327) | – |
| Pain | 8 | 0 (0.500) | −1.67 (0.339) | Standard care 0.16 (0.07 to 0.37) |
| Satisfaction | 6 | −5 (0.174) | −1.26 (0.216) | Immersion 1.73 (1.13 to 2.64) |
| Intact perineum | 14 | −10 (0.340) | 2.13 (0.045) | Standard care 1.71 (1.40 to 2.10) |
| Episiotomy | 13 | −11 (0.274) | −1.27 (0.121) | Immersion 0.20 (0.13 to 0.32) |
| OASI | 14 | 3 (0.435) | 0.40 (0.234) | Standard care 0.64 (0.50 to 0.82) |
| Shoulder dystocia | 7 | 5 (0.226) | 1.85 (0.001) | Standard care 0.68 (0.38 to 1.21) |
| Maternal infection | 3 | – | 0.34 (0.290) | – |
| Postpartum haemorrhage | 13 | 9 (0.328) | −0.23 (0.412) | Standard care 0.52 (0.39 to 0.71) |
| Retained placenta | 5 | 6 (0.071) | 2.11 (0.068) | Standard care 0.76 (0.29 to 2.03) |
| APGAR | 16 | −34 (0.179) | 0.86 (0.209) | Standard care 0.59 (0.36 to 0.96) |
| Neonatal resuscitation | 5 | 2 (0.312) | 0.69 (0.282) | – |
| Transient tachypnoea | 2 | – | – | – |
| Respiratory distress | 3 | 1 (0.301) | −1.77 (0.426) | – |
| Neonatal death | 3 | 1 (0.301) | 1.34 (0.078) | Standard care 0.84 (0.53 to 1.33) |
| Cord avulsion | 5 | 6 (0.071) | 0.36 (0.182) | Standard care 1.86 (1.26 to 2.75) |
| Breastfeeding initiation | 2 | – | – | – |
*Trim-and-fill analysis conducted with random effects model and indicates ORs and 95% CI estimate if bias were corrected.
OASI, obstetric anal sphincter injury.