Summary of findings for the main comparison. Progestogen compared to placebo/no treatment for preventing miscarriage in women with recurrent miscarriage of unclear etiology.
| Progestogen compared to placebo/no treatment for preventing miscarriage in women with recurrent miscarriage of unclear etiology | ||||||
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Patient or population: women with recurrent miscarriage of unclear etiology
Setting: mix of multicenter and single‐center trials based in Egypt, India, Jordan, UK and USA Intervention: progestogen Comparison: placebo/no treatment | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo/no treatment | Risk with progestogen | |||||
| Miscarriage (all trials) | Study population | average RR 0.73 (0.54 to 1.00) | 1684 (10 RCTs) | ⊕⊕⊕⊝ Moderate1 |
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| 275 per 1000 | 201 per 1000 (149 to 275) | |||||
| Live birth rate | Study population | RR 1.07 (1.00 to 1.13) | 1411 (6 RCTs) | ⊕⊕⊕⊝ Moderate1 |
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| 701 per 1000 | 750 per 1000 (701 to 793) | |||||
| Preterm birth | Study population | RR 1.13 (0.53 to 2.41) | 256 (4 RCTs) | ⊕⊝⊝⊝ Very low1,2 | ||
| 75 per 1000 | 84 per 1000 (40 to 180) | |||||
| *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; RCT: randomized controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: 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 certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
1 We downgraded (1) level for serious limitations in study design due to some of the studies being at high or unclear risk for selection bias.
2 We downgraded (2) levels for very serious limitations in imprecision due to small number of events, small sample size and wide CI crossing the line of no effect.