Key messages

• Intravenous (given through a vein) iron probably reduces tiredness slightly at 8 to 28 days compared to oral (by mouth) iron supplements, but we are uncertain if intravenous iron and oral iron supplements compared to oral iron supplements alone affects tiredness at 8 to 28 days.

• We are very uncertain about the effect of red blood cell transfusion compared to intravenous iron on tiredness at 8 to 28 days, and there was no information on red blood cell transfusion compared to no transfusion on tiredness at 8 to 28 days.

• Death of the mother was either not reported, or the evidence was very uncertain for all comparisons. For oral iron compared to placebo (dummy treatment) or no treatment, there was no information on tiredness at 8 to 28 days.

What is iron deficiency anaemia?

Anaemia is a condition where the blood contains less than normal haemoglobin (low blood count), as shown in blood tests. Haemoglobin is the molecule within red blood cells that carries oxygen from the lungs to the tissues. Haemoglobin is a protein that consists of peptides and iron. Insufficient iron intake, problems with absorption of iron in the gut, or iron loss (bleeding) can cause iron deficiency anaemia. Symptoms of anaemia include tiredness, shortness of breath, dizziness, and difficulty getting breastfeeding started. Women may bleed severely at childbirth, and many pregnant women already have low iron stores or anaemia, or both, which can worsen as a result of bleeding. Severe anaemia has been linked to death of the mother after childbirth. Iron deficiency anaemia after childbirth is more likely to occur in low-income countries.

How is postpartum iron deficiency anaemia treated?

Treatment for iron deficiency anaemia includes oral iron supplements or intravenous iron. Studies have found a risk of serious allergic reactions with intravenous iron. Another option is to restore red blood cells through transfusion with blood from a blood donor.

What did we want to find out?

We wanted to know if one treatment was better than another in relieving anaemia symptoms, and whether the treatment options were safe.

What did we do?

We searched medical databases for studies looking at available treatments for women with anaemia after childbirth. We screened studies for trustworthiness and included studies we considered trustworthy. The most important outcomes were fatigue (tiredness) and death.

What did we find?

We included 33 studies with a total of 4558 women and performed seven treatment comparisons.

Eighteen trials (3026 women) compared intravenous iron with oral iron supplements. It is unclear if intravenous iron affects the number of deaths. Only one woman died, and she had received intravenous iron. Based on two studies (515 women), we found that intravenous iron probably reduces fatigue slightly within 8 to 28 days compared to oral iron supplements. No studies examined whether intravenous iron affects breastfeeding. Constipation was probably more frequent in women treated with oral iron supplements than in those receiving intravenous iron (10.7% versus < 1%). It is unclear if intravenous iron has an effect on allergic reactions (anaphylaxis (severe allergic reaction) or hypersensitivity occurred in three women who received intravenous iron). Intravenous iron may increase haemoglobin levels, but important differences among the studies prevented an estimate of the exact effect.

Two studies compared red blood cell transfusions with intravenous iron. It is unclear if red blood cell transfusion affects the number of deaths, fatigue at 8 to 28 days, and breastfeeding. No studies looked at if intravenous iron affects constipation or allergic reactions. Red blood cell transfusion may result in little to no difference in haemoglobin.

Three studies compared intravenous iron and oral iron supplements to oral iron supplementation alone. No studies looked at if intravenous iron and oral iron supplements affects the number of deaths or breastfeeding. It is unclear if intravenous iron and oral iron supplements affects allergic reactions or fatigue. Intravenous iron and oral iron supplementation may reduce constipation compared to oral iron alone (1 study; 128 women) and may result in little to no difference in haemoglobin levels at 8 to 28 days.

One study compared red blood cell transfusions to no transfusions. No studies looked at if red blood cell transfusions affect the number of deaths, fatigue, constipation, allergic reactions, or haemoglobin levels. Red blood cell transfusion may result in little to no difference in breastfeeding beyond six weeks postpartum (1 study; 297 women).

Three studies compared oral iron supplements to placebo. No studies looked at if oral iron supplements affect the number of deaths, fatigue, breastfeeding, allergic reactions, or haemoglobin levels within 8 to 28 days. Two studies reported on constipation not for both groups.

What are the limitations of the evidence?

We have low to very low confidence in the evidence because the women in the studies knew which treatment they received, which could have influenced the results. Also, few studies reported on outcomes that are important to patients. Only 8 of 33 included studies reported on fatigue.

How up-to-date is this evidence?

The evidence is current to April 2024.