Summary of findings for the main comparison.
Aspirin compared with placebo for perineal pain in the early postpartum period
| Aspirin compared with placebo for perineal pain in the early postpartum period | ||||||
|
Patient or population: women with perineal pain in the early postpartum period Settings: 17 RCTs published from 1967 to 1997 (11 RCTs conducted in USA, 3 in Venezuela, 1 each in Belgium, Canada and India) Intervention: aspirin (single dose) Comparison: placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo | Aspirin | |||||
|
Adequate pain relief as reported by the woman (4 to 8 hours) |
Study population | RR 2.03 (1.69, 2.42) | 1001 (13 RCTs) | ⊕⊕⊝⊝ low1 | ||
| 253 per 1000 | 513 per 1000 (427 to 612) | |||||
|
Need for additional pain relief (4 to 8 hours) |
Study population | RR 0.25 (0.17, 0.37) | 744 (10 RCTs) | ⊕⊝⊝⊝ very low1,2 | ||
| 267 per 1000 | 67 per 1000 (45 to 99) | |||||
|
Maternal adverse effects (4 to 8 hours) |
Study population | RR 1.08 (0.57, 2.06) | 1067 (14 RCTs) | ⊕⊝⊝⊝ very low1,3 | ||
| 27 per 1000 | 29 per 1000 (15 to 55) | |||||
| Neonatal adverse effects | (0 RCTs) | Not reported by any of the included RCTs | ||||
| Perineal pain at six weeks postpartum | (0 RCTs) | Not reported by any of the included RCTs | ||||
| *The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; RCT: randomised controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1Study limitations: downgraded two levels due to the serious risk of bias
2Publication bias: downgraded by one level based on visual inspection of funnel plot which indicates likely publication bias
3Imprecision: downgraded one level due to few events and wide 95% CI around the pooled estimate which includes no effect