Table 4.
Periconceptional folic acid supplementation compared to placebo.
| Folic Acid Compared to Placebo for Periconceptional Women | ||||||
|---|---|---|---|---|---|---|
| Patient or population: periconceptional womenSetting: LMICs Intervention: Folic acid Comparison: Placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) |
No. of participants (studies) | Certainty of the evidence (GRADE) |
Comments | |
| Risk with placebo | Risk with folic acid | |||||
| Neural tube defects | Study population | RR = 0.53 (0.41 to 0.67) |
248,056 (2 RCTs) |
⊕⊝⊝⊝ VERY LOW 1 2 |
||
| 2 per 1000 | 1 per 1000 (1 to 1) |
|||||
| *The risk in the intervention group (and its 95% confidence interval) was 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; OR: odds 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. | ||||||