Summary of findings 4. (Maternal outcomes) Any supplements containing iron and folic acid compared with same supplements without iron nor folic acid (no iron nor folic acid or placebo) for pregnant women.
| (Maternal outcomes) Any supplements containing iron and folic acid compared with same supplements without iron nor folic acid (no iron nor folic acid or placebo) | ||||
| Patient or population: Pregnant women of any gestational age and parity Settings: hospital or community‐based antenatal clinics Intervention: Any supplements containing iron and folic acid Comparison: Same supplements without iron nor folic acid (no iron nor folic acid or placebo) | ||||
| Outcomes | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments |
| Maternal anaemia at term (Hb less than 110 g/L at 37 weeks' gestation or more) (ALL) | RR 0.34 (0.21 to 0.54) | 346 (3 RCTs) | ⊕⊕⊕⊝ moderate 1 | |
| Maternal iron deficiency at term (as defined by trialists, based on any indicator of iron status at 37 weeks' gestation or more) (ALL) | RR 0.24 (0.06 to 0.99) | 131 (1 RCT) | ⊕⊕⊝⊝ low 2,3 | |
| Maternal death (death while pregnant or within 42 days of termination of pregnancy) (ALL) | not estimable | 131 (1 RCT) | ⊕⊕⊝⊝ low 2,4 | |
| Side effects (any reported throughout the intervention period) (ALL) | RR 44.32 (2.77 to 709.09) | 456 (1 RCT) | ⊕⊕⊕⊝ moderate 2 | |
| Maternal severe anaemia at any time during second and third trimester (Hb less than 70 g/L) (ALL) | RR 0.12 (0.02 to 0.63) | 506 (4 RCTs) | ⊕⊝⊝⊝ very low 1,5 | |
| Infection during pregnancy (including urinary tract infections) (ALL) | RR 1.00 (0.15 to 6.53) | 48 (1 RCT) | ⊕⊝⊝⊝ very low 2,6 | |
| CI: Confidence interval; RR: risk ratio | ||||
| 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. | ||||
1Studies contributing data had design limitations
2Study contributing data had design limitations
3Estimate based on small sample size
4Small sample size and no events
5Wide 95% CI crossing the line of no effect and low event rate
6Wide 95% CI crossing the line of no effect, small sample size and low event rate