Summary of findings for the main comparison. Levonorgestrel compared to Yuzpe for emergency contraception.
| Levonorgestrel compared to Yuzpe for emergency contraception | ||||||
| Patient or population: Women seeking emergency contraception Setting: China (3), Italy (2), multinational (1); family planning clinics Intervention: Levonorgestrel Comparison: Yuzpe | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with Yuzpe | Risk with Levonorgestrel | |||||
| Observed number of pregnancies (all women) | 29 per 1,000 | 17 per 1,000 (11 to 24) | RR 0.57 (0.39 to 0.84) | 4750 (6 RCTs) | ⊕⊕⊕⊕ HIGH | |
| Any side effect | 681 per 1,000 | 545 per 1,000 (511 to 586) | RR 0.80 (0.75 to 0.86) | 1955 (1 RCT) | ⊕⊕⊕⊕ HIGH | |
| Specific side effects ‐ Nausea | 447 per 1,000 | 179 per 1,000 (161 to 197) | RR 0.40 (0.36 to 0.44) | 4750 (6 RCTs) | ⊕⊕⊕⊝ MODERATE 1 | |
| Specific side effects ‐ Vomiting | 254 per 1,000 | 74 per 1,000 (61 to 89) | RR 0.29 (0.24 to 0.35) | 3640 (5 RCTs) | ⊕⊕⊕⊝ MODERATE 1 | |
| Specific side effects ‐ Spotting/bleeding after treatment | 87 per 1,000 | 158 per 1,000 (119 to 210) | RR 1.82 (1.37 to 2.41) | 1614 (2 RCTs) | ⊕⊕⊕⊝ MODERATE 2 | |
| Menses ‐ Early | 119 per 1,000 | 137 per 1,000 (103 to 182) | RR 1.15 (0.86 to 1.52) | 1310 (2 RCTs) | ⊕⊕⊝⊝ LOW 3 4 | |
| Menses ‐ Delay | 103 per 1,000 | 127 per 1,000 (99 to 162) | RR 1.23 (0.96 to 1.57) | 1988 (3 RCTs) | ⊕⊕⊝⊝ LOW 3 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; OR: Odds 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 | ||||||
1 The quality of evidence was downgraded by one level for “inconsistency” because of high heterogeneity in the meta‐analysis
2 The quality of evidence was downgraded by one level for “imprecision” because the 95% CI overlaps no effect and CI fails to exclude important benefit or important harm.
3 The quality of evidence was downgraded by one level for “ serious risk of bias” associated with poor reporting of randomization methods
4 The quality of evidence was downgraded by one level for “imprecision” because the total (cumulative) sample size is lower than the calculated optimal information size (OIS)