Table 4.
Effect of daily antenatal iron supplementation on selected outcomes, meta‐analysis of randomised controlled trials (Peña‐Rosas et al, 2012).a
| Outcome | Participants, n (trials, n) | Summary measure | Effect (95% CI) | I 2 |
|---|---|---|---|---|
| Maternal haemoglobin concentration at or near term (at 34 weeks gestation or more) | 3704 (19) | Mean difference | 8·9 g/l (7·0–10·8 g/l) | 0·87 |
| Maternal haemoglobin concentration within 6 weeks postpartum, g/l | 956 (7) | Mean difference | 7·6 g/l (5·5–9·7 g/l) | 0·4 |
| Maternal anaemia at term (haemoglobin concentration <110 g/l at 37 weeks of gestation or later) | 2199 (14) | Risk ratio | 0·30 (0·19–0·46) | 0·8 |
| Maternal severe anaemia at postpartum (haemoglobin concentration <80 g/l) | 1339 (8) | Risk ratio | 0·04 (0·01–0·28) | 0 |
| Maternal iron deficiency at term (as defined by researchers, based on any indicator of iron status at 37 weeks gestation or more) | 1256 (7) | Risk ratio | 0·43 (0·27–0·66) | 0·85 |
| Maternal high haemoglobin concentrations at or near term (haemoglobin concentration >130 g/l at 34 weeks gestation or later) | 4850 (9) | Risk ratio | 3·08 (1·28–7·41) | 0·96 |
| Transfusion provided to the mother | 3453 (3) | Risk ratio | 0·61 (0·38–0·96) | 0 |
| Birth weight | 9385 (14) | Mean difference | 30·8 g (5·9–55·7 g) | 0·23 |
| Low birth weight (<2·5 kg) | 8480 (11) | Risk ratio | 0·81 (0·68–0·97) | 0·16 |
| Premature birth (<37 weeks of gestation) | 10 148 (13) | Risk ratio | 0·88 (0·77–1·01) | 0 |
| Infant haemoglobin concentration within the first 6 months; counting the last reported measure after birth within this period | 533 (2) | Mean difference | −1·3 g/l (−8·1 to 5·6 g/l) | 0·89 |
| Infant serum ferritin concentration in the first 6 months; counting the last reported measure after birth within this period | 197 (1) | Mean difference | 11·0 μg/l (4·37–17·63 μg/l) | NA |
NA, not applicable; 95% CI, 95% confidence interval.
a
Any supplements containing iron versus same supplements without iron or no treatment.