Table 10.
Periconceptional iron folic acid supplementation compared to placebo
| Iron folic acid compared to placebo for periconceptional women | ||||||
|---|---|---|---|---|---|---|
| Patient or population: Periconceptional women | ||||||
| Setting: LMICs | ||||||
| Intervention: Iron folic acid | ||||||
| Comparison: Placebo | ||||||
| Outcomes | Anticipated absolute effectsa (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with iron folic acid | |||||
| Anaemia—RCTs | Study population | RR 0.66 (0.53–0.81) | 3430 (6 RCTs) | ⊕⊝⊝⊝ VERY LOW b , c , d | ||
| 565 per 1000 | 350 per 1000 (288–429) | |||||
| Anaemia—Weekly supplementation | Study population | RR 0.70 (0.55–0.88) | 2661 (6 RCTs) | ⊕⊝⊝⊝ VERY LOW b , c , g | ||
| 488 per 1000 | 332 per 1000 (273–405) | |||||
| Anaemia—Daily supplementation | Study population | RR 0.49 (0.21–1.12) | 1532 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW b , c , h | ||
| 417 per 1000 | 213 per 1000 (133–338) | |||||
| Anaemia—8 weeks of weekly supplementation | Study population | RR 1.17 (0.55–1.67) | 159 (1 RCTs) | ⊕⊝⊝⊝ VERY LOW e , f , i | ||
| 249 per 1000 | 237 per 1000(142–394) | |||||
| Anaemia—10 weeks of weekly supplementation | Study population | RR 0.75 (0.64–0.88) | 552 (1 RCT) | ⊕⊕⊝⊝ VERY LOW e , j | ||
| 609 per 1000 | 456 per 1000 (389–536) | |||||
| Anaemia—12 weeks of weekly supplementation | Study population | RR 0.39 (0.27–0.57) | 145 (1 RCTs) | ⊕⊝⊝⊝VERY LOW b , c , e , h | ||
| 398 per 1000 | 187 per 1000 (108–327) | |||||
| Anaemia—14 weeks of weekly supplementation | Study population | RR 0.21 (0.11–0.39) | 139 (1 RCT) | ⊕⊕⊝⊝ LOW e , k | ||
| 653 per 1000 | 137 per 1000 (72–255) | |||||
| Anaemia—16 weeks of weekly supplementation | Study population | RR 0.89 (0.79–0.99) | 1386 (1 RCT) | ⊕⊕⊕⊝ MODERATEj | ||
| 504 per 1000 | 448 per 1000 (398–499) | |||||
| Anaemia—24 weeks of weekly supplementation | Study population | RR 0.85 (0.77–0.94) | 280 (1 RCT) | ⊕⊕⊝⊝ LOW e , l | ||
| 915 per 1000 | 778 per 1000 (704–860) | |||||
| Anaemia—School | Study population | RR 0.66 (0.51–0.86) | 3005 (4 RCTs) | ⊕⊝⊝⊝ VERY LOW b , c , m | ||
| 459 per 1000 | 257 per 1000 (206–326) | |||||
| Anaemia—Work | Study population | RR 0.59 (0.24–1.43) | 425 (2 RCTs) | ⊕⊝⊝⊝VERY LOW e , n , o | ||
| 863 per 1000 | 509 per 1000 (207–1000) | |||||
Note: 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.
Abbreviations: CI, confidence interval; OR, odds ratio; RR, risk ratio.
The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
Some studies use multiple micro nutrients in the intervention arm.
Multiple studies with large weight are at high risk for bias.
Heterogeneity is 84%.
Total number of events is <300.
One study uses vitamin C along with iron‐folic acid in the intervention arm.
Heterogeneity is 82%.
Heterogeneity is 76%.
One study is at high risk of bias.
Study is at risk of performance and reporting bias.
Study is at risk of other biases.
It is mostly unclear if study is at risk of bias.
Heterogeneity is 83%.
Heterogeneity is 95%.
One study is at risk of attrition bias.