Please could you tell us a little bit about anemia?
Anaemia is a condition in which the number of red blood cells in the body is lower than normal or these have lower amounts of haemoglobin, a protein that is involved in the oxygen exchange of the body.
It is calculated that 41.8% of pregnant women worldwide are anaemic. At least half of this anaemia burden is assumed to be due to iron deficiency, with the rest due to other conditions such as folate, vitamin B12 or vitamin A deficiencies, chronic inflammation, parasitic infections and inherited blood disorders.
Clinical symptoms of anaemia are frequently non-specific but it can be diagnosed by a quick laboratory test. A pregnant woman is considered to be anaemic if her haemoglobin concentration during the first and third trimester of gestation is lower than 110 g/l, at sea level; in the second trimester of pregnancy, the haemoglobin concentration usually decreases by approximately 5 g/. When anaemia is caused by iron deficiency (e.g. low ferritin levels), it is referred to as iron deficiency anaemia.
Why are some pregnant women affected by anemia?
During pregnancy, women need iron and folic acid to meet their own needs and those of their developing fetus. Most women may require additional iron intake to ensure sufficient iron stores during pregnancy to prevent iron deficiency. Since many women begin pregnancy with low iron stores, they are more likely to develop anaemia.
Why is it important to prevent anemia in pregnancy?
It is important to prevent both low and high haemoglobin concentrations.
Low haemoglobin concentrations indicative of moderate or severe anaemia during pregnancy have been associated with an increased risk of low birth weight, premature delivery, maternal and child mortality, and infectious diseases. There are also indications that growth and development may also be affected, both in utero and in the long term.
Conversely, haemoglobin concentrations greater than 130 g/l at sea level may also be associated with negative pregnancy outcomes such as premature delivery and low birth weight.
What had previously been used to prevent anemia in pregnancy?
The use of daily iron and folic acid supplements throughout pregnancy has been the standard approach to cover this gap and in turn prevent and treat iron deficiency anaemia.
Despite its proven efficacy, the use of daily iron supplementation has been limited in programme settings, possibly due to a lack of compliance because of common side-effects (e.g. nausea, constipation, dark stools or metallic taste), concerns about the safety of this intervention among women with an adequate iron intake, and variable availability of the supplements at community level.
Your recent research suggests taking iron supplements one to three times a week was just as effective as taking them every day. What do you think the reason for this is?
Intermittent use of oral iron supplements (i.e. once, twice or three times a week on non-consecutive days) has been proposed as an effective alternative to daily iron supplementation for prevention of anaemia in women of reproductive age, including those who are pregnant.
This intervention was first proposed in the early 90’s. The rationale behind this intervention has traditionally been that intestinal cells turn over every 5–6 days and have limited iron absorptive capacity. Thus intermittent provision of iron would expose only the new intestinal epithelial cells to this nutrient, which, in theory, should improve its absorption.
Although the data is still limited, the findings of our review suggest that intermittent iron+folic acid regimens produce similar maternal and infant outcomes at birth (for example anaemia at term, preterm birth or low birth at weight) as daily supplementation but are associated with fewer side effects.
Did you find that the required iron supplements were dependent on the severity of the anemia?
This is a plausible statement as women would have a larger iron gap to cover. However, we did not assess it in our review. We attempted to assess the effects of iron supplementation on severe anaemia but found that such women are excluded from participation before the trials start or withdrawn during the course of intervention to further receive higher doses of daily iron supplements. In general there was a poor documentation of all these cases.
How did your research originate?
In some countries, authorities are in need of guidance on the effectiveness and safety of different schemes of iron and folic acid supplementation in pregnant women as a public health measure to improve pregnancy outcomes in support of their efforts to achieve the Millennium Development Goals.
Different regimens, such as the intermittent iron supplementation, the use of slow release iron supplements or lower doses of iron in daily regimens have been evaluated. Since anaemia is a global problem, countries are looking for options to improve adherence to the intervention and prevent iron deficiency anaemia in pregnancy and in general during the life cycle.
Do you have any further plans for more research into this area?
There are many things to do and understand in this area. For example, there is a need to determine what is the most effective and safe weekly dose of iron and folic acid to improve folate status in order to improve pregnancy outcomes and to determine whether the addition of other vitamins and minerals to the iron tablet provided weekly will provide additional benefits. All the team of authors aim to maintain this review current and update it as new research is available.
How do you see the future of prevention of anemia in pregnancy progressing?
It is important to distinguish this preventive approach from the therapeutic approach. Intermittent iron supplementation may be a feasible intervention in countries where there is adequate antenatal care and where women have good dietary sources of iron through a varied and balanced diet. It would be important to avoid waiting until they become anaemic to treat and thus, in these settings, intermittent iron supplementation might be a potential intervention to consider.
Where can readers find out more information about your work?
The full review with open access is available at the Cochrane Library at this link: http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009997/abstract
About Juan Pablo Peña-Rosas
Dr JP Pena-Rosas is the Coordinator, Evidence and Programme Guidance, Department of Nutrition for Health and Development at the World Health Organization (WHO) in Geneva, Switzerland. He joined WHO on July 2008 and now oversees the Evidence and Programme Guidance work plan, in the development of evidence-informed guidelines for interventions addressing the double burden of malnutrition for neonates, infants, children and women in stable and emergency settings, under the WHO Research Strategy umbrella.
He is an Adjunct Assistant Professor at Emory University Rollins School of Public Health in Atlanta, United States since 2011. Previously, he worked several years in the Division of Nutrition, Physical Activity and Obesity at the Centers for Disease Control and Prevention (CDC) in Atlanta, United States. He was involved in nutrition surveys, and programme monitoring and evaluation for nutrition interventions in Uzbekistan, Morocco, Egypt, Peru, Nicaragua, Georgia and Dominican Republic.
He received his Medical Degree from Universidad Central de Venezuela in his native country and a Master’s Degree in Public Health Nutrition from University of Puerto Rico in San Juan. He holds a PhD in Human Nutrition and Epidemiology from Cornell University, Ithaca, NY, United States of America. He is a member of the American Society for Nutrition, Latin American Society of Nutrition, the American Evaluation Association, the Cochrane Collaboration and the WHO Guidelines Review Committee 2010-2012.