Summary of findings for the main comparison. Intrauterine administration of hCG for women undergoing assisted reproduction.
| Intrauterine administration of hCG for women undergoing assisted reproduction | |||||
| Patient or population: subfertile women undergoing assisted reproduction Setting: assisted reproduction units Intervention: intrauterine human chorionic gonadotropin (hCG) Comparison: no intrauterine hCG | |||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Certainty of the evidence (GRADE) | |
| Risk with no hCG | Risk with intrauterine human chorionic gonadotropin (hCG) | ||||
| Live birth Cleavage stage: hCG < 500 IU Follow‐up: mean 40 weeks Cleavage stage: hCG ≥ 500 IU Follow‐up: mean 40 weeks Blastocyst stage: hCG ≥ 500 IU Follow‐up: mean 40 weeks |
495 per 1000 | 376 per 1000 (287 to 500) | RR 0.76 (0.58 to 1.01) | 280 (1 RCT) | ⊕⊝⊝⊝ VERY LOWa,b |
| 273 per 1000 | 428 per 1000 (360 to 510) | RR 1.57 (1.32 to 1.87) | 914 (3 RCTs) | ⊕⊕⊕⊝ MODERATEc | |
| 369 per 1000 | 340 per 1000 (296 to 384) | RR 0.92 (0.80 to 1.04) | 1666 (2 RCTs) | ⊕⊕⊕⊝ MODERATEc | |
| Miscarriage Follow‐up: mean 40 weeks | 58 per 1000 | 60 per 1000 (47 to 78) | RR 1.04 (0.81 to 1.35) | 3927 (11 RCTs) | ⊕⊝⊝⊝ VERY LOWc,d |
| Clinical pregnancy Cleavage stage:
hCG < 500 IU
Follow‐up: mean 12 weeks Cleavage stage: hCG ≥ 500 IU Follow‐up: mean 12 weeks Blastocyst stage: hCG ≥ 500 IU Follow‐up: mean 12 weeks |
579 per 1000 | 509 per 1000 (405 to 637) | RR 0.88 (0.70 to 1.10) | 280 (1 RCT) | ⊕⊝⊝⊝ VERY LOWa,d |
| 307 per 1000 | 458 per 1000 (406 to 517) | RR 1.49 (1.32 to 1.68) | 2186 (12 RCTs) | ⊕⊕⊕⊝ MODERATEc | |
| 422 per 1000 | 418 per 1000 (359 to 485) | RR 0.99 (0.85 to 1.15) | 2091 (4 RCTs) | ⊕⊕⊕⊝ MODERATEc | |
| Complications Follow‐up: mean 40 weeks | Other complications reported in the included studies were ectopic pregnancy (4 RCTs; N = 1073; 4 events overall), heterotopic pregnancy (1 RCT; N = 495; 1 event), intrauterine death (3 RCTs; N = 1078; 22 events), and triplets (1 RCT; N = 48; 3 events). No evidence shows a difference between groups, but events were too few for any conclusions to be drawn. | ‐ | 1764 (7 RCTs) | ⊕⊝⊝⊝ VERY LOWc,d | |
| *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; hCG: human chorionic gonadotropin; 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. | |||||
aDowngraded two levels for very serious risk of bias: lack of blinding of participants and personnel, no clear description of allocation concealment, and premature termination of the study following interim analysis. bDowngraded one level for serious imprecision: total events were fewer than 300. cDowngraded one level for serious risk of bias: lack of blinding of participants and personnel, no allocation concealment. dDowngraded two levels for very serious imprecision: total number of events was less than 300, and 95% confidence interval around the pooled effect includes both no effect and appreciable benefit or appreciable harm.