Iron Supplements in Pregnancy: New Benefits?

Healthnotes Newswire (May 4, 2006)—Do pregnant women need iron in their prenatal supplements? If they are not anemic and have adequate stores of iron, the answer has been “probably not,” at least during the first two trimesters. However, new research shows potential benefits beyond correcting iron deficiency when iron supplements are taken by low-income women starting early in their pregnancies.

“Iron supplementation, when begun early in pregnancy, improved the birth weights of the babies,” said Dr. Anna Maria Siega-Riz, associate professor of maternal and child health at the University of North Carolina School of Public Health and lead author on the study.

According to the March of Dimes, low birth weight affects about 1 in every 13 babies born each year in the United States. It increases the risk of infant death, serious health problems, and long-term disabilities.

In the new study, published in the American Journal of Obstetrics and Gynecology, 429 women who were not anemic and who had sufficient iron stores in their tissue were randomly assigned to take prenatal multivitamins providing either 30 mg of iron per day (as ferrous sulfate) or no iron. They began taking the vitamins during their first prenatal visit and continued until the 26th to 29th week of pregnancy. There was no significant effect on the iron status of the women taking the iron-containing supplements, probably because they already had adequate stores. However, the average birth weight was higher in the group taking supplements.

Iron is an essential trace metal used to transport oxygen from the blood into the body’s cells. The body needs more oxygen during pregnancy, so the need for iron also increases, especially in the third trimester. A pregnant woman’s body compensates for its increased iron needs by absorbing more iron from food. Though this is sometimes enough to meet the needs of the mother and fetus, many women require additional iron supplementation.

Iron deficiency at the beginning of pregnancy can be due to poor diet, menstrual losses, or other factors. Healthy, nonpregnant women should not supplement with iron unless they have an iron deficiency proven by a blood test. Every pregnant woman should have her iron status checked early in pregnancy (or better yet, prior to conception) and again 20 weeks into the pregnancy. These tests can usually identify a need for extra iron during the remainder of pregnancy and for several months after delivery.

Babies born into low-income families may be more at risk for low birth weight. “Pregnant women with low income may want to consider iron supplementation, even if their blood levels and iron stores are normal,” said Dr. Siega-Riz. “It is not expensive, and definitely worth discussing with their obstetrician.”

(Am J Obstet Gynecol 2006;194:512–9.)

Jeremy Appleton, ND, CNS, is a licensed naturopathic physician, certified nutrition specialist, and published author. Dr. Appleton was the Nutrition Department Chair at the National College of Naturopathic Medicine, has served on the faculty at Bastyr University of Natural Health Sciences, and is a former Healthnotes Senior Science Editor and a founding contributor to Healthnotes Newswire. He has worked extensively in scientific and regulatory affairs in the supplement industry and is now a consultant through his company Praxis Natural Products Consulting and Wellness Services.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.