Summary of findings for the main comparison. Myo‐inositol for preventing gestational diabetes maternal outcomes (maternal outcomes).
| Antenatal supplementation with myo‐inositol for preventing gestational diabetes | ||||||
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Patient or population: pregnant women (women with pre‐existing type 1 or type 2 diabetes are NOT included)
Intervention: Myo‐inositol Setting: Italy Comparison: Control | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with control | Risk with Myo‐inositol | |||||
| Gestational diabetes mellitus | Study population | RR 0.43 (0.29 to 0.64) | 502 (3 RCTs) | ⊕⊕⊝⊝ LOW 1 2 | GDM diagnosed using IADPSG 2010 criteria | |
| 28 per 100 | 12 per 100 (8 to 18) | |||||
| Weight gain during pregnancy | The mean weight gain during pregnancy was 0 | The mean weight gain during pregnancy in the intervention group was 0.64 more (0.41 fewer to 1.7 more) | ‐ | 411 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW 2 3 4 | D'Anna 2015 included obese pregnant women and D'Anna 2013 included non‐obese women with a family history of type 2 diabetes Random‐effects model |
| Hypertensive disorders of pregnancy | Study population | RR 0.43 (0.02 to 8.41) | 398 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW 2 5 6 | Random‐effects model | |
| 4 per 100 | 2 per 100 (0 to 33) | |||||
| Caesarean section | Study population | RR 0.95 (0.76 to 1.19) | 398 (2 RCTs) | ⊕⊕⊝⊝ LOW 2 6 | ||
| 45 per 100 | 43 per 100 (34 to 54) | |||||
| Perineal trauma | Not estimable | (0 studies) | No data reported for perineal trauma in any of the included studies | |||
| Postnatal depression | Not estimable | (0 studies) | No data reported for postnatal depression in any of the included studies | |||
| Type 2 diabetes | Not estimable | (0 studies) | No data reported for type 2 diabetes in any of the included studies | |||
| *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 | ||||||
1 Downgraded (‐1) due to unclear risk of bias for allocation concealment in two of the included trials (one trial did not provide sufficient detail to determine allocation concealment and one trial (reported as a conference abstract) had no details of random sequence generation, allocation concealment or blinding) and for high risk of performance bias for lack of blinding (two trials were open‐label trials with no blinding of participants or researchers, however one trial explicitly described blinding of outcome assessors and was assessed as low risk of detection bias).
2 Studies were conducted in Italy with Caucasian women and generalisability of findings is limited, downgraded (‐1).
3 Evidence of imprecision with wide confidence intervals crossing the line of no effect, downgraded (‐1).
4 Heterogeneity high with I2 = 54% (indirectness) probably due to different study populations, downgraded (‐1).
5 Wide confidence intervals with very low event rates and a small sample size suggest evidence of imprecision, downgraded (‐1).
6 Downgraded (‐1) due to insufficient evidence to judge allocation concealment in one trial and subsequent judgement of unclear risk of bias. The other trial had a low risk of bias for allocation concealment. Both trials were open‐label with no blinding of participants or researchers, although one trial explicitly stated that outcome assessors were blinded to treatment allocation.