A study by researchers from the Maternal and Perinatal Research collaboration, India (MaatHRI) published in the American Journal of Hematology has found that 57% of antenatal and 61% of postnatal women included in the study had anaemia, despite receiving supplementation. Therefore, the strategy for universal routine iron supplementation in pregnancy needs rethinking to achieve the World Health Organization (WHO)’s target of a 50% reduction of anaemia in women of reproductive age by 2025.
An estimated 36% of all pregnant women globally have anaemia, a condition where the body does not produce enough red blood cells or the haemoglobin concentration falls below a specific level. This can cause a greater risk of complications before and after birth. There are many causes of anaemia including vitamin deficiencies, infections, or chronic inflammation, but the major cause of anaemia in pregnancy in low- and middle-income countries is thought to be iron deficiency.
India is one of ten countries where more than 50% of pregnant and postpartum women are estimated to have anaemia and this has not changed since 2000, despite free routine iron and folic acid supplementation being recommended for all pregnant women for 180 days starting from the second trimester of pregnancy and for 180 days after giving birth.
There is currently limited evidence about the prevalence of iron deficiency anaemia in pregnant and postpartum women in low- and middle-income countries due to a lack of low-cost and reliable tests that can measure iron levels. This means that healthcare practitioners rely on haemoglobin levels as an indicator for iron deficiency anaemia (IDA), even though low haemoglobin concentration may not be caused by IDA.
In this study, the researchers examined the relationship between anaemia of different levels of severity and four biomarkers, or indicators, for iron levels in pregnant and postpartum women in India. They focused on two groups of women who were either pregnant (antenatal) or postnatal with uncomplicated pregnancies.
They analysed levels of ferritin (a protein that stores iron in the blood) in both pregnant and postpartum women, and soluble transferrin receptor, transferrin saturation (measures of iron status used to investigate IDA), and hepcidin (a protein that regulates the entry of iron into the circulation) in postpartum women. These analyses enabled the researchers to examine whether or not low haemoglobin is an effective way of measuring iron levels in the body.
- despite a high proportion of women receiving iron and folic acid supplementation, 57% of antenatal and 61% of postnatal women included in the study had anaemia;
- the prevalence of moderate anaemia (32% in the antenatal group; 31% in the postnatal group) and severe anaemia (3% in the antenatal group; 4% in the postnatal group) were similar in the two groups, although there was a higher prevalence of mild anaemia in the postnatal group (26%, compared with 21% in the antenatal group);
- around one-third of the women (34% in the antenatal group; 40% in the postnatal group) had iron deficiency based on low ferritin levels but 4% in the antenatal group and 6% in the postnatal group had high ferritin levels.
- among women without anaemia, 17% - 57% had iron deficiency depending on the iron biomarker that was used for the analysis (27% had low ferritin levels, 17% had high soluble transferrin receptor levels, and 57% had low transferrin saturation);
- overall, haemoglobin was poorly associated with all four of the biomarkers for iron levels in the body analysed in this study, indicating that low haemoglobin alone is not a useful measure of iron deficiency in pregnant and postpartum women.
Associate Professor Manisha Nair, lead author, said ‘Ours is the first study of its kind to examine in detail the relationship between anaemia and iron biomarkers in a low- and middle-income country. We have demonstrated that there are multiple causes of anaemia, therefore prevention, control, and treatment of anaemia in pregnancy should be guided by detection of the cause of anaemia in the population. It is also important for clinical trials of oral and intravenous iron to include iron biomarkers and not just haemoglobin to determine effectiveness.’
Professor Elizabeta Nemeth, President, International BioIron Society, and Professor of Medicine, University of California, Los Angeles, and co-author of the paper said, ‘We have shown that measuring haemoglobin levels alone is not a useful indicator of iron deficiency and there is a need to develop low-cost reliable tests that are able to measure different iron biomarkers in order to ascertain the need for supplementation and treatment.’
The levels of severity of anaemia referenced in the study were defined using the World Health Organization’s definitions: mild anaemia, haemoglobin 10-10.9 g/dL; moderate 7-9.9 g/dL; and severe <7 g/dL.