Summary of findings 3. Low‐dose mifepristone (< 25 mg) versus levonorgestrel 1.5 mg for emergency contraception.
| Low‐dose mifepristone (< 25 mg) versus levonorgestrel 1.5 mg for emergency contraception | ||||||
| Patient or population: women seeking emergency contraception Setting: China (12), UK (1), multinational (1); family planning clinics Intervention: mifepristone, low dose (< 25 mg) Comparison: levonorgestrel 1.5 mg | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with levonorgestrel 1.5 mg | Risk with low‐dose mifepristone (< 25 mg) | |||||
| Observed number of pregnancies (all women) | 20 per 1000 | 15 per 1000 (10 to 20) | RR 0.72 (0.52 to 0.99) | 8752 (14 RCTs) | ⊕⊕⊕⊕ High | |
| Any side effect | 342 per 1000 | 89 per 1000 (58 to 130) | RR 0.26 (0.17 to 0.38) | 609 (3 RCTs) | ⊕⊕⊝⊝ Low1,2 | |
| Specific side effect ‐ nausea | 133 per 1000 | 126 per 1000 (112 to 145) | RR 0.95 (0.84 to 1.09) | 6384 (5 RCTs) | ⊕⊕⊕⊝ Moderate3 | |
| Specific side effect ‐ vomiting | 15 per 1000 | 19 per 1000 (8 to 41) | RR 1.22 (0.55 to 2.68) | 6085 (3 RCTs) | ⊕⊕⊝⊝ Low3,4 | |
| Specific side effect ‐ spotting/bleeding after treatment | 284 per 1000 | 173 per 1000 (153 to 196) | RR 0.61 (0.54 to 0.69) | 4598 (5 RCTs) | ⊕⊕⊕⊕ High | |
| Menses ‐ early | 182 per 1000 | 82 per 1000 (64 to 108) | RR 0.45 (0.35 to 0.59) | 1800 (5 RCTs) | ⊕⊕⊝⊝ Low1,2 | |
| Menses ‐ delay | 66 per 1000 | 113 per 1000 (98 to 131) | RR 1.70 (1.48 to 1.97) | 7520 (9 RCTs) | ⊕⊕⊝⊝ Low1,4 | |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High quality: we are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect Very low quality: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect | ||||||
1We downgraded the quality of evidence by one level for serious risk of bias associated with poor reporting of randomization methods. 2We downgraded the quality of evidence by one level for imprecision because the total (cumulative) sample size was lower than the calculated optimal information size. 3We downgraded the quality of evidence by one level for imprecision because the 95% CI overlaps no effect and CI fails to exclude important benefit or important harm. 4We downgraded the quality of evidence by one level for inconsistency because of high heterogeneity in the meta‐analysis.