Summary of findings for the main comparison. Progesterone compared to placebo or no treatment for treating threatened miscarriage.
| Progesterone compared to placebo or no treatment for treating threatened miscarriage | ||||||
| Patient or population: women with threatened miscarriage Setting: two in high‐income countries (Germany and Italy), four in upper‐middle income countries (two in Iran, one in Malaysia and one in Turkey) and one in lower‐income country (Jordan). All in hospitals (university or women's) or medical centres Intervention: progesterone Comparison: placebo or no treatment | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (trials) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo or no treatment | Risk with progesterone | |||||
| Miscarriage | Study population | RR 0.64 (0.47 to 0.87) | 696 (7 RCTs) | ⊕⊕⊕⊝ Moderate1 | ||
| 242 per 1000 | 138 per 1000 (102 to 189) | |||||
| Preterm birth | Study population | RR 0.86 (0.52 to 1.44) | 588 (5 RCTs) | ⊕⊕⊝⊝ Low1, 2 | ||
| 91 per 1000 | 84 per 1000 (49 to 142) | |||||
| Congential abnormalities | Study population | RR 0.70 (0.10 to 4.82) | 337 (2 RCTs) | ⊕⊝⊝⊝ Very low1, 2, 3 | ||
| 13 per 1000 | 9 per 1000 (1 to 62) | |||||
| *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: randomised 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. | ||||||
1Random sequence generation and/or allocation concealment had a high or unclear risk of bias in the majority of the trials (methodological quality of trials) (‐1). 2Wide confidence interval crossing the no effect line (imprecision) (‐1). 3A small number of events (‐1).