Abstract
A total of 33 randomized controlled trials involving 4558 postpartum women were included in the review.
- Intravenous iron probably reduces fatigue slightly within 8 to 28 days compared to oral iron.
- The evidence is very uncertain regarding the effects of intravenous iron on mortality and anaphylaxis or hypersensitivity.
- Oral iron supplementation is likely to increase the risk of constipation compared to intravenous iron.
- Red blood cell transfusion may show little to no difference in haemoglobin levels within 8 to 28 days.
- The effects of red blood cell transfusion on mortality, fatigue, and breastfeeding remain very uncertain.
- The impact of oral iron supplementation on mortality, fatigue, breastfeeding, constipation, and haemoglobin is unreported.
AI simplified
RATIONALE: Postpartum iron deficiency anaemia is caused by antenatal iron deficiency or excessive blood loss at delivery and might affect up to 50% of labouring women in low- and middle-income countries. Effective and safe treatment during early motherhood is important for maternal well-being and newborn care. Treatment options include oral iron supplementation, intravenous iron, erythropoietin, and red blood cell transfusion.
OBJECTIVES: To assess the benefits and harms of the available treatment modalities for women with postpartum iron deficiency anaemia. These include intravenous iron, oral iron supplementation, red blood cell transfusion, and erythropoietin.
SEARCH METHODS: A Cochrane Information Specialist searched for all published, unpublished, and ongoing trials, without language or publication status restrictions. We searched databases including CENTRAL, MEDLINE, Embase, CINAHL, LILACS, WHO ICTRP, and ClinicalTrials.gov, together with reference checking, citation searching, and contact with study authors to identify eligible studies. We applied date limits to retrieve new records since the last search on 9 April 2015 until 11 April 2024.
ELIGIBILITY CRITERIA: We included published, unpublished, and ongoing randomised controlled trials (RCTs) that compared treatments for postpartum iron deficiency anaemia with placebo, no treatment, or alternative treatments. Cluster-randomised trials were eligible for inclusion. We included RCTs regardless of blinding. Participants were women with postpartum haemoglobin ≤ 12 g/dL, treated within six weeks after childbirth. We excluded non-randomised, quasi-randomised, and cross-over trials.
OUTCOMES: The critical outcomes of this review were maternal mortality and fatigue. The important outcomes included persistent anaemia symptoms, persistent postpartum anaemia, psychological well-being, infections, compliance with treatment, breastfeeding, length of hospital stay, serious adverse events, anaphylaxis or evidence of hypersensitivity, flushing/Fishbane reaction, injection discomfort/reaction, constipation, gastrointestinal pain, number of red blood cell transfusions, and haemoglobin levels.
RISK OF BIAS: We assessed risk of bias in the included studies using the Cochrane RoB 1 tool.
SYNTHESIS METHODS: Two review authors independently performed study screening, risk of bias assessment, and data extraction. We contacted trial authors for supplementary data when necessary. We screened all trials for trustworthiness and scientific integrity using the Cochrane Trustworthiness Screening Tool. We conducted meta-analyses using a fixed-effect model whenever feasible to synthesise outcomes. In cases where data were not suitable for meta-analysis, we provided a narrative summary of important findings. We evaluated the overall certainty of the evidence using GRADE.
INCLUDED STUDIES: We included 33 RCTs with a total of 4558 postpartum women. Most trials were at high risk of bias for several risk of bias domains.
SYNTHESIS OF RESULTS: Most of the evidence was of low or very low certainty. Imprecision due to few events and risk of bias due to lack of blinding were the most important factors. Intravenous iron versus oral iron supplementation The evidence is very uncertain about the effect of intravenous iron on mortality (risk ratio (RR) 2.95, 95% confidence interval (CI) 0.12 to 71.96; P = 0.51; I² = not applicable; 3 RCTs; 1 event; 572 women; very low-certainty evidence). One woman died of cardiomyopathy, and another developed arrhythmia, both in the groups treated with intravenous iron. Intravenous iron probably results in a slight reduction in fatigue within 8 to 28 days (standardised mean difference -0.25, 95% CI -0.42 to -0.07; P = 0.006; I² = 47%; 2 RCTs; 515 women; moderate-certainty evidence). Breastfeeding was not reported. Oral iron probably increases the risk of constipation compared to intravenous iron (RR 0.12, 95% CI 0.06 to 0.21; P < 0.001; I² = 0%; 10 RCTs; 1798 women; moderate-certainty evidence). The evidence is very uncertain about the effect of intravenous iron on anaphylaxis or hypersensitivity (RR 2.77, 95% CI 0.31 to 24.86; P = 0.36; I² = 0%; 12 RCTs; 2195 women; very low-certainty evidence). Three women treated with intravenous iron experienced anaphylaxis or hypersensitivity. The trials that reported on haemoglobin at 8 to 28 days were too heterogeneous to pool. However, 5 of 6 RCTs favoured intravenous iron, with mean changes in haemoglobin ranging from 0.73 to 2.10 g/dL (low-certainty evidence). Red blood cell transfusion versus intravenous iron No women died in the only trial that reported on mortality (1 RCT; 7 women; very low-certainty evidence). The evidence is very uncertain about the effect of red blood cell transfusion on fatigue at 8 to 28 days (mean difference (MD) 1.20, 95% CI -2.41 to 4.81; P = 0.51; I² = not applicable; 1 RCT; 13 women; very low-certainty evidence) and breastfeeding more than six weeks postpartum (RR 0.43, 95% CI 0.12 to 1.57; P = 0.20; I² = not applicable; 1 RCT; 13 women; very low-certainty evidence). Constipation and anaphylaxis were not reported. Red blood cell transfusion may result in little to no difference in haemoglobin within 8 to 28 days (MD -1.00, 95% CI -2.02 to 0.02; P = 0.05; I² = not applicable; 1 RCT; 12 women; low-certainty evidence). Intravenous iron and oral iron supplementation versus oral iron supplementation Mortality and breastfeeding were not reported. One trial reported a greater improvement in fatigue in the intravenous and oral iron group, but the effect size could not be calculated (1 RCT; 128 women; very low-certainty evidence). Intravenous iron and oral iron may result in a reduction in constipation compared to oral iron alone (RR 0.21, 95% CI 0.07 to 0.69; P = 0.01; I² = not applicable; 1 RCT; 128 women; low-certainty evidence). There were no anaphylaxis or hypersensitivity events in the trials (2 RCTs; 168 women; very low-certainty evidence). Intravenous iron and oral iron may result in little to no difference in haemoglobin (g/dL) at 8 to 28 days (MD 0.00, 95% CI -0.48 to 0.48; P = 1.00; I² = not applicable; 1 RCT; 60 women; low-certainty evidence). Red blood cell transfusion versus no transfusion Mortality, fatigue at day 8 to 28, constipation, anaphylaxis, and haemoglobin were not reported. Red blood cell transfusion may result in little to no difference in breastfeeding more than six weeks postpartum (RR 0.91, 95% CI 0.78 to 1.07; P = 0.24; I² = not applicable; 1 RCT; 297 women; low-certainty evidence). Oral iron supplementation versus placebo or no treatment Mortality, fatigue, breastfeeding, constipation, anaphylaxis, and haemoglobin were not reported. Two trials reported on gastrointestinal symptoms, but did not report results by study arm.
AUTHORS' CONCLUSIONS: Intravenous iron probably reduces fatigue slightly in the early postpartum weeks (8 to 28 days) compared to oral iron tablets, but probably results in little to no difference after four weeks. It is very uncertain if intravenous iron has an effect on mortality and anaphylaxis/hypersensitivity. Breastfeeding was not reported. Intravenous iron may increase haemoglobin slightly more than iron tablets, but the data were too heterogeneous to pool. However, changes in haemoglobin levels are a surrogate outcome, and treatment decisions should preferentially be based on patient-relevant outcomes. Iron tablets probably result in a large increase in constipation compared to intravenous iron. The effect of red blood cell transfusion compared to intravenous iron on mortality, fatigue, and breastfeeding is very uncertain. No studies reported on constipation or anaphylaxis/hypersensitivity. Red blood cell transfusion may result in little to no difference in haemoglobin at 8 to 28 days. The effect of intravenous iron and oral iron supplementation on mortality, fatigue, breastfeeding, and anaphylaxis/hypersensitivity is very uncertain or unreported. Intravenous iron and oral iron may result in a reduction in constipation compared to oral iron alone, and in little to no difference in haemoglobin. The effect of red blood cell transfusion compared to non-transfusion on mortality, fatigue, constipation, anaphylaxis/hypersensitivity, and haemoglobin is unreported. Red blood cell transfusion may result in little to no difference in breastfeeding. The effect of oral iron supplementation on mortality, fatigue, breastfeeding, constipation, anaphylaxis/hypersensitivity, and haemoglobin is unreported.
FUNDING: This Cochrane review had no dedicated funding.
REGISTRATION: Protocol and previous versions are available: Protocol (2013) [DOI: 10.1002/14651858.CD010861] Original review (2004) [DOI: 10.1002/14651858.CD004222.pub2] Review update (2015) [DOI: 10.1002/14651858.CD010861.pub2].