Intermittent use of supplements with iron alone or with other micronutrients versus no supplementation or placebo in menstruating women

Patient or population: Menstruating women

Settings: All settings including malaria-endemic areas

Intervention: Intermittent supplementation of iron alone or with any other micronutrients

Comparison: Placebo or no intervention

OutcomesRelative effect
(95% CI)
Number of participants
(studies)
Quality of the evidence
(GRADE)*
Comments
Anaemia (as defined by the trialists)RR 0.73
(0.56–0.95)
2996
(10 studies)
⊕⊕⊖⊖
low1,2
Iron deficiency anaemia (anaemia and one indicator of iron deficiency)RR 0.07
(0–1.16)
97
(1 study)
⊕⊖⊖⊖
very low1,3,4
Only one study reported on this outcome
Iron deficiency (as defined by the trialists)RR 0.5
(0.24–1.04)
624
(3 studies)
⊕⊕⊖⊖
low1,3
All-cause morbidityRR 1.12
(0.82–1.52)
119
(1 study)
⊕⊖⊖⊖
very low1,4
Only one study reported on this outcome
Haemoglobin (g/l)MD 4.58
(2.56–6.59)
2599
(13 studies)
⊕⊕⊖⊖
low1,2
Ferritin (μg/l)MD 8.32
(4.97–11.66)
980
(6 studies)
⊕⊕⊖⊖
low1,3

CI, confidence interval; RR, risk ratio; MD, mean difference.

*

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 have moderate confidence 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 the effect.

1

In several trials, the method of allocation concealment was not clear and there was lack of blinding.

2

There was high heterogeneity and some inconsistency in the direction of the effect.

3

Wide confidence intervals.

4

Only one study reported on this outcome.

Note: For cluster-randomized trials the analyses only include the estimated effective sample size, after adjusting the data to account for the clustering effect.

For details of studies included in the review, see reference (15).

From: Annex 1, GRADE “Summary of findings” tables

Cover of Guideline: Intermittent Iron and Folic Acid Supplementation in Menstruating Women
Guideline: Intermittent Iron and Folic Acid Supplementation in Menstruating Women.
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