A new study published in The Journal of Nutrition provides evidence that current iron supplementation standards for pregnant women may not be sufficient to prevent iron deficiency during the later stages of pregnancy.

To meet increased iron needs during pregnancy, the Recommended Dietary Allowance increases to 27 mg of iron daily throughout pregnancy. As this amount is difficult to obtain via diet alone, public health agencies recommend daily supplementation with an iron-containing prenatal multivitamin. Whether this amount is enough to prevent iron deficiency in pregnancy is unclear and warrants further investigation. To bridge this knowledge gap, a team of researchers led by Crystal Karakochuk (University of British Columbia) assessed iron status in early and late pregnancy among 60 pregnant women receiving 27 mg of iron per day as part of a randomized trial.

All participants were instructed to take 1 prenatal multivitamin in the morning and 1 in the evening. Each prenatal multivitamin provided 13.5 mg of iron, which provided a total of 27 mg of iron per day. Blood samples were collected between 8 – 21 and 24 – 38 weeks of gestation, respectively. Levels of iron and inflammatory biomarkers and rates of iron deficiency, anemia, and iron-deficiency anemia were measured.

High rates of iron deficiency were observed in this generally healthy, low-risk, pregnant cohort in both early and later pregnancy. At baseline, 28% of women had ferritin concentrations, a protein that stores iron in cells, indicative of iron deficiency. At endline, the vast majority (81%) were likely iron deficient. This occurred despite the provision of 27 mg of iron daily throughout the study. While iron deficiency did not progress to iron-deficiency anemia, proteins found in the blood that become elevated prior to iron deficiency anemia increased.

Iron deficiency remains a significant and largely neglected concern during pregnancy. Not only did this study find high rates of iron deficiency, but also questions if standard prenatal multivitamins are insufficient to maintain ferritin concentrations throughout pregnancy. This study provides evidence that women may require additional iron, beyond 27 mg daily, to support needs into later states of pregnancy. The authors also stress the importance of incorporating the assessment of iron status into routine perinatal clinical practice guidelines to ensure that iron deficiency is addressed and that an optimal iron status is maintained throughout all of pregnancy.

In a companion commentary, Dr. Michael Auerbach (Georgetown University) underscores the need for widespread screening and treatment of iron deficiency during pregnancy, given its effects on fetal growth and development.


Kelsey M Cochrane, Jennifer A Hutcheon, Crystal D Karakochuk, Iron-Deficiency Prevalence and Supplementation Practices Among Pregnant Women: A Secondary Data Analysis From a Clinical Trial in Vancouver, Canada, The Journal of Nutrition, Volume 152, Issue 10, October 2022, Pages 2238–2244, https://doi.org/10.1093/jn/nxac135.

Michael Auerbach, A Step Forward in the Management of Gestational Iron Deficiency, The Journal of Nutrition, Volume 152, Issue 10, October 2022, Pages 2184–2185, https://doi.org/10.1093/jn/nxac169.

Images via canva.com.