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. 2015 Jul 22;2015(7):CD004736. doi: 10.1002/14651858.CD004736.pub5

Comparison 3. Supplementation with iron alone versus no treatment/placebo.

Outcome or subgroup title No. of studies No. of participants Statistical method Effect size
1 Low birthweight (less than 2500 g) (ALL) 6 1136 Risk Ratio (M‐H, Random, 95% CI) 0.63 [0.30, 1.32]
2 Low birthweight (less than 2500 g): SUBGROUP ANALYSIS by gestational age at the start of supplementation 6 1136 Risk Ratio (M‐H, Random, 95% CI) 0.63 [0.30, 1.32]
2.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 2 361 Risk Ratio (M‐H, Random, 95% CI) 0.32 [0.15, 0.70]
2.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 3 665 Risk Ratio (M‐H, Random, 95% CI) 1.05 [0.50, 2.19]
2.3 Unspecified or mixed gestational age at the start of supplementation 1 110 Risk Ratio (M‐H, Random, 95% CI) 1.79 [0.17, 19.20]
3 Low birthweight (less than 2500 g): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 6 1136 Risk Ratio (M‐H, Random, 95% CI) 0.63 [0.30, 1.32]
3.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
3.2 Non‐anaemic at start of supplementation 5 955 Risk Ratio (M‐H, Random, 95% CI) 0.65 [0.25, 1.66]
3.3 Unspecified or mixed anaemic status at start of supplementation 1 181 Risk Ratio (M‐H, Random, 95% CI) 0.57 [0.14, 2.31]
4 Low birthweight (less than 2500 g): SUBGROUP ANALYSIS by dose of iron 6 1136 Risk Ratio (M‐H, Random, 95% CI) 0.63 [0.30, 1.32]
4.1 Low daily dose (30 mg elemental iron or less) 3 697 Risk Ratio (M‐H, Random, 95% CI) 0.59 [0.12, 2.96]
4.2 Medium daily dose (31 to 59 mg elemental iron) 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
4.3 Higher daily dose (60 mg elemental iron and above) 3 439 Risk Ratio (M‐H, Random, 95% CI) 0.62 [0.25, 1.50]
5 Low birthweight (less than 2500 g): SUBGROUP ANALYSIS by malarial status of setting 6 1136 Risk Ratio (M‐H, Random, 95% CI) 0.63 [0.30, 1.32]
5.1 Malarial setting 2 329 Risk Ratio (M‐H, Random, 95% CI) 0.52 [0.20, 1.35]
5.2 Non‐malarial setting 4 807 Risk Ratio (M‐H, Random, 95% CI) 0.73 [0.20, 2.70]
6 Birthweight (g) (ALL) 9 1331 Mean Difference (IV, Random, 95% CI) ‐1.04 [‐78.77, 76.70]
7 Birthweight (g): SUBGROUP ANALYSIS by gestational age at the start of supplementation 9 1331 Mean Difference (IV, Random, 95% CI) ‐1.04 [‐78.77, 76.70]
7.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 5 477 Mean Difference (IV, Random, 95% CI) ‐31.62 [‐214.93, 151.70]
7.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 4 854 Mean Difference (IV, Random, 95% CI) ‐8.70 [‐74.71, 57.31]
7.3 Unspecified or mixed gestational age at the start of supplementation 0 0 Mean Difference (IV, Random, 95% CI) 0.0 [0.0, 0.0]
8 Birthweight (g): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 9 1331 Mean Difference (IV, Random, 95% CI) ‐1.04 [‐78.77, 76.70]
8.1 Anaemic at start of supplementation 0 0 Mean Difference (IV, Random, 95% CI) 0.0 [0.0, 0.0]
8.2 Non‐anaemic at start of supplementation 7 961 Mean Difference (IV, Random, 95% CI) ‐9.03 [‐125.10, 107.04]
8.3 Unspecified or mixed anaemic status at start of supplementation 2 370 Mean Difference (IV, Random, 95% CI) 0.90 [‐86.32, 88.12]
9 Birthweight (g): SUBGROUP ANALYSIS by dose of iron 9 1331 Mean Difference (IV, Random, 95% CI) ‐1.70 [‐72.00, 70.60]
9.1 Low daily dose (30 mg elemental iron or less) 4 785 Mean Difference (IV, Random, 95% CI) 46.83 [‐76.57, 170.22]
9.2 Medium daily dose (31 to 59 mg elemental iron) 0 0 Mean Difference (IV, Random, 95% CI) 0.0 [0.0, 0.0]
9.3 Higher daily dose (60 mg elemental iron and above) 6 546 Mean Difference (IV, Random, 95% CI) ‐36.28 [‐126.66, 54.10]
10 Birthweight (g): SUBGROUP ANALYSIS by malarial status of setting 9 1331 Mean Difference (IV, Random, 95% CI) ‐1.04 [‐78.77, 76.70]
10.1 Malarial setting 2 345 Mean Difference (IV, Random, 95% CI) 33.74 [‐61.16, 128.65]
10.2 Non‐malarial setting 7 986 Mean Difference (IV, Random, 95% CI) ‐21.75 [‐132.94, 89.44]
11 Preterm birth (less than 37 weeks of gestation) (ALL) 6 1713 Risk Ratio (M‐H, Random, 95% CI) 0.82 [0.58, 1.14]
12 Preterm birth (less 37 weeks of gestation): SUBGROUP ANALYSIS by gestational age at the start of supplementation 6 1713 Risk Ratio (M‐H, Random, 95% CI) 0.82 [0.58, 1.14]
12.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 4 1236 Risk Ratio (M‐H, Random, 95% CI) 0.92 [0.62, 1.35]
12.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 2 477 Risk Ratio (M‐H, Random, 95% CI) 0.58 [0.29, 1.13]
12.3 Unspecified or mixed gestational age at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
13 Preterm birth (less 37 weeks of gestation): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 6 1713 Risk Ratio (M‐H, Random, 95% CI) 0.82 [0.58, 1.14]
13.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
13.2 Non‐anaemic at start of supplementation 5 851 Risk Ratio (M‐H, Random, 95% CI) 0.72 [0.45, 1.13]
13.3 Unspecified or mixed anaemic status at start of supplementation 1 862 Risk Ratio (M‐H, Random, 95% CI) 0.95 [0.58, 1.57]
14 Preterm birth (less 37 weeks of gestation): SUBGROUP ANALYSIS by dose of iron 6 1713 Risk Ratio (M‐H, Random, 95% CI) 0.82 [0.58, 1.14]
14.1 Low daily dose (30 mg elemental iron or less) 3 690 Risk Ratio (M‐H, Random, 95% CI) 0.76 [0.47, 1.24]
14.2 Medium daily dose (31 to 59 mg elemental iron) 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
14.3 Higher daily dose (60 mg elemental iron and above) 3 1023 Risk Ratio (M‐H, Random, 95% CI) 0.87 [0.54, 1.39]
15 Preterm birth (less 37 weeks of gestation): SUBGROUP ANALYSIS by malarial status of setting 6 1713 Risk Ratio (M‐H, Random, 95% CI) 0.82 [0.58, 1.14]
15.1 Malarial setting 2 1010 Risk Ratio (M‐H, Random, 95% CI) 0.87 [0.54, 1.39]
15.2 Non‐malarial setting 4 703 Risk Ratio (M‐H, Random, 95% CI) 0.76 [0.47, 1.24]
16 Neonatal death (within 28 days after delivery) (ALL) 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
17 Congenital anomalies (ALL) 2 2402 Risk Ratio (M‐H, Random, 95% CI) 0.86 [0.55, 1.35]
18 Maternal anaemia at term (Hb less than 110 g/L at 37 weeks' gestation or more) (ALL) 14 2136 Risk Ratio (M‐H, Random, 95% CI) 0.29 [0.19, 0.47]
19 Maternal anaemia at term (Hb less than 110 g/L at 37 weeks' gestation or more): SUBGROUP ANALYSIS by gestational age at the start of supplementation 13 1999 Risk Ratio (M‐H, Random, 95% CI) 0.25 [0.16, 0.41]
19.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 6 549 Risk Ratio (M‐H, Random, 95% CI) 0.18 [0.06, 0.57]
19.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 6 1301 Risk Ratio (M‐H, Random, 95% CI) 0.32 [0.20, 0.53]
19.3 Unspecified or mixed gestational age at start of supplementation 1 149 Risk Ratio (M‐H, Random, 95% CI) 0.03 [0.00, 0.18]
20 Maternal anaemia at term (Hb less than 110 g/L at 37 weeks gestation or more): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 13 1936 Risk Ratio (M‐H, Random, 95% CI) 0.25 [0.15, 0.42]
20.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
20.2 Non‐anaemic at start of supplementation 8 1244 Risk Ratio (M‐H, Random, 95% CI) 0.20 [0.10, 0.44]
20.3 Unspecified or mixed anaemic status at start of supplementation 5 692 Risk Ratio (M‐H, Random, 95% CI) 0.34 [0.18, 0.64]
21 Maternal anaemia at term (Hb less than 110 g/L at 37 weeks' gestation or more): SUBGROUP ANALYSIS by dose of iron 13 1999 Risk Ratio (M‐H, Random, 95% CI) 0.25 [0.16, 0.41]
21.1 Low daily dose (30 mg elemental iron or less) 3 590 Risk Ratio (M‐H, Random, 95% CI) 0.49 [0.24, 1.03]
21.2 Medium daily dose (31 to 59 mg elemental iron) 1 69 Risk Ratio (M‐H, Random, 95% CI) 0.21 [0.06, 0.73]
21.3 Higher daily dose (60 mg elemental iron and above) 9 1340 Risk Ratio (M‐H, Random, 95% CI) 0.19 [0.10, 0.38]
22 Maternal anaemia at term (Hb less than 110 g/L at 37 weeks' gestation or more): SUBGROUP ANALYSIS by malarial status of setting 13 1936 Risk Ratio (M‐H, Random, 95% CI) 0.25 [0.15, 0.42]
22.1 Malarial setting 2 267 Risk Ratio (M‐H, Random, 95% CI) 0.58 [0.46, 0.72]
22.2 Non‐malarial setting 11 1669 Risk Ratio (M‐H, Random, 95% CI) 0.18 [0.10, 0.34]
23 Maternal iron deficiency at term (as defined by trialists, based on any indicator of iron status at 37 weeks' gestation or more) (ALL) 7 1256 Risk Ratio (M‐H, Random, 95% CI) 0.43 [0.27, 0.66]
24 Maternal iron deficiency at term (as defined by trialists, based on any indicator of iron status at 37 weeks' gestation or more): SUBGROUP ANALYSIS by gestational age at the start of supplementation 7 1256 Risk Ratio (M‐H, Random, 95% CI) 0.43 [0.27, 0.66]
24.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 4 653 Risk Ratio (M‐H, Random, 95% CI) 0.45 [0.22, 0.93]
24.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 3 603 Risk Ratio (M‐H, Random, 95% CI) 0.36 [0.18, 0.72]
24.3 Unspecified or mixed gestational age at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
25 Maternal iron deficiency at term (as defined by trialists, based on any indicator of iron status at 37 weeks' gestation or more): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 7 1256 Risk Ratio (M‐H, Random, 95% CI) 0.43 [0.27, 0.66]
25.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
25.2 Non‐anaemic at start of supplementation 5 1092 Risk Ratio (M‐H, Random, 95% CI) 0.56 [0.39, 0.82]
25.3 Unspecified or mixed anaemic status at start of supplementation 2 164 Risk Ratio (M‐H, Random, 95% CI) 0.14 [0.07, 0.29]
26 Maternal iron deficiency at term (as defined by trialists, based on any indicator of iron status at 37 weeks' gestation or more): SUBGROUP ANALYSIS by dose of iron 7 1256 Risk Ratio (M‐H, Random, 95% CI) 0.43 [0.27, 0.66]
26.1 Low daily dose (30 mg elemental iron or less) 3 703 Risk Ratio (M‐H, Random, 95% CI) 0.52 [0.34, 0.78]
26.2 Medium daily dose (31 to 59 mg elemental iron) 1 241 Risk Ratio (M‐H, Random, 95% CI) 0.92 [0.73, 1.17]
26.3 Higher daily dose (60 mg elemental iron and above) 3 312 Risk Ratio (M‐H, Random, 95% CI) 0.21 [0.10, 0.41]
27 Maternal iron deficiency at term (as defined by trialists, based on any indicator of iron status at 37 weeks' gestation or more): SUBGROUP ANALYSIS by malarial status of setting 7 1256 Risk Ratio (M‐H, Random, 95% CI) 0.43 [0.27, 0.66]
27.1 Malarial setting 2 192 Risk Ratio (M‐H, Random, 95% CI) 0.28 [0.15, 0.53]
27.2 Non‐malarial setting 5 1064 Risk Ratio (M‐H, Random, 95% CI) 0.49 [0.30, 0.78]
28 Maternal iron‐deficiency anaemia at term (Hb less than 110 g/L and at least one additional laboratory indicators at 37 weeks' gestation or more) (ALL) 6 1088 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
29 Maternal iron‐deficiency anaemia at term (Hb less than 110 g/L and at least one additional laboratory indicators at 37 weeks' gestation or more): SUBGROUP ANALYSIS by gestational age at the start of supplementation 6 1088 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
29.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 4 660 Risk Ratio (M‐H, Random, 95% CI) 0.39 [0.13, 1.11]
29.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 2 428 Risk Ratio (M‐H, Random, 95% CI) 0.25 [0.11, 0.58]
29.3 Unspecified or mixed gestational age at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
30 Maternal iron‐deficiency anaemia at term (Hb less than 110 g/L and at least one additional laboratory indicators at 37 weeks' gestation or more): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 6 1088 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
30.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
30.2 Non‐anaemic at start of supplementation 5 968 Risk Ratio (M‐H, Random, 95% CI) 0.39 [0.20, 0.74]
30.3 Unspecified or mixed anaemic status at start of supplementation 1 120 Risk Ratio (M‐H, Random, 95% CI) 0.04 [0.00, 0.72]
31 Maternal iron‐deficiency anaemia at term (Hb less than 110 g/L and at least one additional laboratory indicators at 37 weeks' gestation or more): SUBGROUP ANALYSIS by dose of iron 6 1088 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
31.1 Daily low dose (60 mg elemental iron or less) 3 579 Risk Ratio (M‐H, Random, 95% CI) 0.38 [0.13, 1.11]
31.2 Medium dose (31 to 59 mg elemental iron) 1 241 Risk Ratio (M‐H, Random, 95% CI) 0.34 [0.16, 0.70]
31.3 High dose (60 mg elemental iron and above) 2 268 Risk Ratio (M‐H, Random, 95% CI) 0.04 [0.00, 0.72]
32 Maternal iron‐deficiency anaemia at term (Hb less than 110 g/L and at least one additional laboratory indicators at 37 weeks' gestation or more): SUBGROUP ANALYSIS by malarial status of setting 6 1088 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
32.1 Malarial setting 1 148 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
32.2 Non‐malarial setting 5 940 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
33 Maternal death (death while pregnant or within 42 days of termination of pregnancy) (ALL) 1 47 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
34 Side effects (any reported throughout the intervention period) (ALL) 9 1677 Risk Ratio (M‐H, Random, 95% CI) 1.59 [1.00, 2.52]
35 Side effects (any reported throughout the intervention period): SUBGROUP ANALYSIS by gestational age at the start of supplementation 9 1677 Risk Ratio (M‐H, Random, 95% CI) 1.59 [1.00, 2.52]
35.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 3 438 Risk Ratio (M‐H, Random, 95% CI) 1.38 [0.87, 2.19]
35.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 5 1034 Risk Ratio (M‐H, Random, 95% CI) 1.42 [0.89, 2.28]
35.3 Unspecified or mixed gestational age at start of supplementation 1 205 Risk Ratio (M‐H, Random, 95% CI) 62.79 [3.89, 1013.31]
36 Side effects (any reported throughout the intervention period): SUBGROUP ANALYSIS by anaemia status at the start of supplementation 9 1677 Risk Ratio (M‐H, Random, 95% CI) 1.59 [1.00, 2.52]
36.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
36.2 Non‐anaemic at start of supplementation 5 900 Risk Ratio (M‐H, Random, 95% CI) 1.08 [0.91, 1.28]
36.3 Unspecified or mixed anaemic status at start of supplementation 4 777 Risk Ratio (M‐H, Random, 95% CI) 5.11 [0.78, 33.60]
37 Side effects (any reported throughout the intervention period): SUBGROUP ANALYSIS by dose of iron 9 1677 Risk Ratio (M‐H, Random, 95% CI) 1.58 [1.02, 2.43]
37.1 Low daily dose (30 mg elemental iron or less) 4 785 Risk Ratio (M‐H, Random, 95% CI) 1.07 [0.90, 1.26]
37.2 Medium daily dose (31 to 59 mg elemental iron) 2 225 Risk Ratio (M‐H, Random, 95% CI) 2.00 [0.66, 6.02]
37.3 Higher daily dose (60 mg elemental iron and above) 5 667 Risk Ratio (M‐H, Random, 95% CI) 5.53 [0.81, 37.89]
38 Side effects (any reported throughout the intervention period): SUBGROUP ANALYSIS by malarial status of setting 9 1677 Risk Ratio (M‐H, Random, 95% CI) 1.59 [1.00, 2.52]
38.1 Malarial setting 1 205 Risk Ratio (M‐H, Random, 95% CI) 62.79 [3.89, 1013.31]
38.2 Non‐malarial setting 8 1472 Risk Ratio (M‐H, Random, 95% CI) 1.40 [0.99, 1.97]
39 Maternal severe anaemia at any time during second and third trimester (Hb less than 70 g/L) (ALL) 7 1078 Risk Ratio (M‐H, Random, 95% CI) 0.75 [0.02, 29.10]
40 Maternal severe anaemia at any time during second and third trimester (Hb less than 70 g/L): SUBGROUP ANALYSIS by gestational age at the start of supplementation 7 1078 Risk Ratio (M‐H, Random, 95% CI) 0.75 [0.02, 29.10]
40.1 Early gestational age (less than 20 weeks of gestation or pre‐pregnancy) at start of supplementation 3 416 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
40.2 Late gestational age (20 weeks or more of gestation) at start of supplementation 3 513 Risk Ratio (M‐H, Random, 95% CI) 0.75 [0.02, 29.10]
40.3 Unspecified or mixed gestational age at start of supplementation 1 149 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
41 Maternal severe anaemia at any time during second and third trimester (Hb less than 70 g/L): SUBGROUP ANALYSIS by anaemia status age at the start of supplementation 7 1078 Risk Ratio (M‐H, Random, 95% CI) 0.75 [0.02, 29.10]
41.1 Anaemic at start of supplementation 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
41.2 Non‐anaemic at start of supplementation 5 816 Risk Ratio (M‐H, Random, 95% CI) 4.98 [0.24, 103.01]
41.3 Unspecified or mixed anaemic status at start of supplementation 2 262 Risk Ratio (M‐H, Random, 95% CI) 0.12 [0.01, 2.21]
42 Maternal severe anaemia at any time during second and third trimester (Hb less than 70 g/L): SUBGROUP ANALYSIS by dose of iron 7 1078 Risk Ratio (M‐H, Random, 95% CI) 0.75 [0.02, 29.10]
42.1 Low daily dose (30 mg elemental iron or less) 3 654 Risk Ratio (M‐H, Random, 95% CI) 4.98 [0.24, 103.01]
42.2 Medium daily dose (31 to 59 mg elemental iron) 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
42.3 Higher daily dose (60 mg elemental iron and above) 4 424 Risk Ratio (M‐H, Random, 95% CI) 0.12 [0.01, 2.21]
43 Maternal severe anaemia at any time during second and third trimester (Hb less than 70 g/L): SUBGROUP ANALYSIS by malarial status of setting 7 1078 Risk Ratio (M‐H, Random, 95% CI) 0.75 [0.02, 29.10]
43.1 Malarial setting 1 55 Risk Ratio (M‐H, Random, 95% CI) 0.12 [0.01, 2.21]
43.2 Non‐malarial setting 6 1023 Risk Ratio (M‐H, Random, 95% CI) 4.98 [0.24, 103.01]
44 Maternal clinical malaria 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
45 Infection during pregnancy (including urinary tract infections) (ALL) 0 0 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
46 Very low birthweight (less than 1500 g) (ALL) 3 697 Risk Ratio (M‐H, Random, 95% CI) 0.55 [0.03, 9.07]
47 Very premature birth (less than 34 weeks' gestation) (ALL) 3 690 Risk Ratio (M‐H, Random, 95% CI) 0.32 [0.10, 1.09]
48 Infant Hb concentration in the first 6 months (in g/L, counting the last reported measure after birth within this period) (ALL) 2 533 Mean Difference (IV, Random, 95% CI) ‐1.25 [‐8.10, 5.59]
49 Infant serum ferritin concentration in the first 6 months (in μg/L, counting the last reported measure after birth within this period) (ALL) 1 197 Mean Difference (IV, Random, 95% CI) 11.0 [4.37, 17.63]
50 Admission to special care unit (ALL) 1 111 Risk Ratio (M‐H, Random, 95% CI) 0.0 [0.0, 0.0]
51 Maternal anaemia at or near term (Hb less than 110 g/L at 34 weeks' gestation or more) (ALL) 13 1696 Risk Ratio (M‐H, Random, 95% CI) 0.29 [0.18, 0.46]
52 Maternal iron deficiency at or near term (as defined by trialists, based on any indicator of iron status at 34 weeks' gestation or more) (ALL) 7 1256 Risk Ratio (M‐H, Random, 95% CI) 0.43 [0.27, 0.66]
53 Maternal iron‐deficiency anaemia at or near term (Hb less than 110 g/L and at least one additional laboratory indicators at 34 weeks' gestation or more) (ALL) 6 1088 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.16, 0.69]
54 Maternal Hb concentration at or near term (in g/L, at 34 weeks' gestation or more) (ALL) 16 1851 Mean Difference (IV, Random, 95% CI) 8.95 [6.37, 11.53]
55 Maternal Hb concentration within 6 wk postpartum (in g/L) (ALL) 6 659 Mean Difference (IV, Random, 95% CI) 7.26 [4.78, 9.74]
56 Maternal high haemoglobin concentrations during second or third trimester (Hb more than 130 g/L) (ALL) 7 1146 Risk Ratio (M‐H, Random, 95% CI) 1.90 [1.07, 3.35]
57 Maternal high haemoglobin concentrations at or near term (Hb more than 130 g/L at 34 weeks' gestation or more) (ALL) 7 1189 Risk Ratio (M‐H, Random, 95% CI) 3.80 [1.74, 8.28]
58 Moderate anaemia at postpartum (Hb more than 80 g/L and less than 110 g/L) (ALL) 3 453 Risk Ratio (M‐H, Random, 95% CI) 0.46 [0.02, 13.91]
59 Maternal severe anaemia at or near term (Hb less than 70 g/L at 34 weeks' gestation or more) (ALL) 7 1046 Risk Ratio (M‐H, Random, 95% CI) 0.74 [0.02, 27.81]
60 Severe anaemia at postpartum (Hb less than 80 g/L) (ALL) 7 953 Risk Ratio (M‐H, Random, 95% CI) 0.02 [0.00, 0.33]
61 Puerperal infection (ALL) 2 2292 Risk Ratio (M‐H, Random, 95% CI) 0.65 [0.41, 1.03]
62 Antepartum haemorrhage (ALL) 1 430 Risk Ratio (M‐H, Random, 95% CI) 2.97 [0.12, 72.56]
63 Postpartum haemorrhage (ALL) 3 761 Risk Ratio (M‐H, Random, 95% CI) 0.82 [0.51, 1.34]
64 Transfusion provided (ALL) 1 32 Risk Ratio (M‐H, Random, 95% CI) 0.33 [0.01, 7.62]
65 Diarrhoea (ALL) 1 173 Risk Ratio (M‐H, Random, 95% CI) 0.98 [0.09, 10.61]
66 Constipation (ALL) 2 580 Risk Ratio (M‐H, Random, 95% CI) 0.88 [0.18, 4.40]
67 Nausea (ALL) 3 650 Risk Ratio (M‐H, Random, 95% CI) 2.38 [0.49, 11.52]
68 Heartburn (ALL) 1 408 Risk Ratio (M‐H, Random, 95% CI) 1.0 [0.82, 1.22]
69 Vomiting (ALL) 2 477 Risk Ratio (M‐H, Random, 95% CI) 0.88 [0.38, 2.07]
70 Maternal wellbeing/satisfaction (ALL) 1 49 Risk Ratio (M‐H, Random, 95% CI) 0.91 [0.77, 1.08]
71 Placental abruption (ALL) 1 1442 Risk Ratio (M‐H, Random, 95% CI) 2.88 [0.12, 70.53]
72 Premature rupture of membranes (ALL) 1 72 Risk Ratio (M‐H, Random, 95% CI) 0.2 [0.01, 4.03]
73 Pre‐eclampsia (ALL) 1 47 Risk Ratio (M‐H, Random, 95% CI) 0.96 [0.06, 14.43]