Summary of findings 1. Preconception lifestyle advice on a combination of topics compared to routine care or attention control for people with infertility.
| Preconception lifestyle advice on a combination of topics compared to routine care or attention control for people with infertility | |||||||
| Patient or population: people with infertility Setting: university/hospital Intervention: preconception lifestyle advice on a combination of topics Comparison: routine care or attention control | |||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | №. of participants (studies) | Certainty of the evidence (GRADE) | Comments | ||
| Risk with routine care or attention control | Risk with preconception lifestyle advice on a combination of topics | ||||||
| Live birth | 481 per 1000 | 447 per 1000 (380 to 529) | RR 0.93 (0.79 to 1.10) | 626 (1 RCT) | ⊕⊕⊝⊝ LOWa,b | Preconception lifestyle advice on a combination of topics may result in little to no difference in live birth | |
| Adverse events | ‐ | ‐ | ‐ | ‐ | ‐ | No studies reported on this outcome | |
| Miscarriage | ‐ | ‐ | ‐ | ‐ | ‐ | No studies reported on this outcome | |
| Reported behavioural changes in weight: BMI (measured "at study end" ‐ 3 months) |
Mean reported behavioural changes in weight: BMI was 25.52 kg/m² | MD 1.06 kg/m² lower (2.33 lower to 0.21 higher) | ‐ | 180 (1 RCT) | ⊕⊝⊝⊝ VERY LOWa,b,c,d | Evidence is very uncertain about the effects on BMI of preconception lifestyle advice on a combination of topics | |
| Reported behavioural changes in diet: vegetable intake assessed with lifestyle questionnaire (measured at 3 months) | Mean reported behavioural changes in diet: vegetable intake was 135.2 grams/d | MD 12.5 grams/d higher (8.43 lower to 33.43 higher) | ‐ | 264 (1 RCT) | ⊕⊝⊝⊝ VERY LOWd,e | Evidence is very uncertain about the effects on vegetable intake of preconception lifestyle advice on a combination of topics | |
| Reported behavioural changes on vitamin or mineral supplement intake: number of women with adequate use of folic acid supplement assessed with lifestyle questionnaire (measured at 3 and 6 months) | 933 per 1000 | 915 per 1000 (887 to 943) | RR 0.98 (0.95 to 1.01) | 850 (2 RCTs) | ⊕⊕⊝⊝ LOWe | Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women with adequate use of folic acid supplement, but the quality of the evidence was low | |
| Reported behavioural changes in alcohol intake (measured at 6 months) | Number of women abstaining from alcohol assessed with lifestyle questionnaire | 750 per 1000 | 803 per 1000 (742 to 878) | RR 1.07 (0.99 to 1.17) | 607 (1 RCT) | ⊕⊕⊝⊝ LOWe | Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women abstaining from alcohol, but the quality of the evidence was low |
| Number of men abstaining from alcohol assessed with lifestyle questionnaire | 321 per 1000 | 347 per 1000 (238 to 507) | RR 1.08 (0.74 to 1.58) | 210 (1 RCT) | ⊕⊝⊝⊝ VERY LOWe,f | Evidence is very uncertain about the effect on the number of men abstaining from alcohol of preconception lifestyle advice on a combination of topics | |
| Reported behavioural changes in smoking (measured at 6 months): | Number of women not smoking assessed with lifestyle questionnaire | 951 per 1000 | 961 per 1000 (932 to 989) | RR 1.01 (0.98 to 1.04) | 606 (1 RCT) | ⊕⊕⊝⊝ LOWe | Preconception lifestyle advice on a combination of topics may result in little to no difference in the number of women not smoking, but the quality of the evidence was low |
| Number of men not smoking assessed with lifestyle questionnaire | 873 per 1000 | 881 per 1000 (794 to 977) | RR 1.01 (0.91 to 1.12) | 212 (1 RCT) | ⊕⊝⊝⊝ VERY LOWd,e | Evidence is very uncertain about the effect on the number of men not smoking of preconception lifestyle advice on a combination of topics | |
| *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). BMI: body mass index; CI: confidence interval; MD: mean difference; RCT: randomised controlled trial; RR: risk ratio. | |||||||
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GRADE Working Group grades of evidence. High quality: further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: we are very uncertain about the estimate. | |||||||
aDowngraded by one level for serious risk of bias: high risk for performance bias and at multiple domains, unclear risk of bias.
bDowngraded by one level for serious imprecision: optimal information size (OIS) not met.
cDowngraded by one level for serious indirectness: differences in intervention (one study has traditional medicine‐oriented diet regimen).
dDowngraded by one level for serious imprecision: one study, few patients (< 400).
eDowngraded by two levels for very serious risk of bias: high risk for performance, detection, and reporting bias and at multiple domains, unclear risk of bias.
fDowngraded by two levels for very serious imprecision: one study, few events (< 400) and 95% CI includes important benefit and harm.