For more than 50 years, pregnant women have been advised to take iron supplements daily. New research coming from Children’s Hospital & Research Center Oakland suggests that weekly iron-folate supplementation at lower doses might be much more beneficial.
Iron deficiency is a world-wide health problem, but in pregnant women in particular, iron deficiency—especially during the first and second trimester—can cause premature delivery, low birth weight, even death if anemia is severe. As a result, iron supplementation has long been recognized as a therapeutic tool for treating iron deficiency and anemia in pregnant women.
For the last 10 years however, Fernando Viteri, MD, ScD, a scientist at the Children’s Hospital Oakland Research Institute, has been leading a quiet revolution to shift from daily supplementation, to weekly supplementation.
“Now there are over 90 papers showing weekly doses are effective in improving iron reserves and even correcting moderate anemia,” says Dr. Viteri. “Infants in France, school children in Guatemala and Colombia, adolescents in Malaysia, infants in China, Mexico, Venezuela —all these different populations show the same thing.”
Yet more compelling, however, are the results of Dr. Viteri’s latest study in collaboration with scientists at the National Institute of Perinatology in Mexico on hemoglobin concentrations and pregnancy outcomes in non-anemic women.
This study shows for the first time that daily iron-folate supplementation at the iron doses recommended for pregnant women in iron-deficient populations by the World Health Organization (WHO) and the Centers for Disease Control (CDC) is significantly correlated with a greater risk of low birth weight and premature delivery–due not to iron deficiency, but to iron excess and high hemoglobin levels, which epidemiologic studies have shown carry equal if not greater outcome risks.
“What happened was that hemoglobin went up and up, so that by the end of the second trimester of pregnancy, 27 percent of the women on 60 mg of iron a day had hemoglobin levels that were undesirably high, increasing the risk of low birth weight and of premature delivery by four times in those women,” explains Dr. Viteri.
In contrast, only 7 percent of the women on weekly supplements developed high hemoglobin levels. This strongly suggests that the recommended daily iron doses are too high. As Dr. Viteri points out, “More is not always better.”
Studies like this one, in combination with the many Dr. Viteri has already produced, are slowly leading to a revision of the WHO/CDC recommendations that have been recommended for nearly 50 years.
“Changing criteria like this takes time,” admits Dr. Viteri. “We have to be patient.”
Patient, perhaps, but not complicit. Dr. Viteri continues to press the issue, with three more studies soon to be published building on this same data.
For more information about dietary iron needs, visit the National Institutes of Health Web site at http://dietarysupplements.info.nih.gov/factsheets/iron.asp.