Ask a Dietitian

As seen on BCTV Noon News

Meeting iron requirements during pregnancy can be very difficult for the average mother to do. If iron stores are not sufficient it can lead to iron deficiency (ID) and iron deficiency anemia (IDA), both of which are common amongst pregnant women. It is the result of the mother’s expanding blood volume to support the growing fetus and placenta. Therefore, meeting iron requirements is extremely important for both mother and baby’s health.

What are the consequences of iron deficiency (ID) and iron deficiency anemia (IDA)?

ID and IDA can contribute to the following:

In the mother:

In the baby:

How can I prevent iron deficiency and iron deficiency anemia?

Currently the recommended daily allowance (RDA) of iron for pregnant women is set at 27 mg per day. However, Canadian Guidelines for the management of Anemia have stated that consuming approximately 20-30 mg of iron per day is sufficient throughout pregnancy. While eating a diet rich in iron sources and foods that enhance the absorption of iron is important, it can sometimes be difficult for women to meet these requirements purely from food. It is during the 2^nd and 3^rd trimester that the iron requirement increases. Some recommend starting iron supplements at the first prenatal visit, whereas the Institute of Medicine recommends it for the 2^nd and 3^rd trimesters only. Largely, when to begin supplementation may be recommended on an individual basis, depending on the individual’s susceptibility, history and intake of iron rich food sources.  

To date there have been no adverse effects of iron supplementation on the actual pregnancy outcome and it has been shown to improve the hematological parameters of the mother. However, some women have found that the high iron content of their prenatal vitamins has contributed to gastrointestinal (GI) problems, such as nausea, constipation and upper abdominal discomfort. New research has found that a lower dose iron supplement still gives the same protection against ID and IDA, but has a lower risk factor for the uncomfortable side effects. A study published in the 2003 American Journal of Clinical Nutrition, found that fewer women from the iron-supplemented group than from the placebo had ID (35% versus 58% respectively) with no significant difference in GI side effects between the groups. Presently, Dr. Fay Weisberg, Assistant Professor, University of Toronto, Department of Obstetrics and Gynecology, is reformulating the 60 mg of iron in the leading prenatal vitamin, Materna, to 27 mg which meets the current RDA of iron for pregnant women. Lastly, administering the iron supplement daily has been shown to have superior results as opposed to weekly administration.  

The Bottom Line:  Iron is an important trace mineral for you and your baby and meeting your daily requirement can greatly reduce your chances of becoming iron deficient.  Low-dose iron supplementation regimens have been found to be an effective alternative to high-dose iron supplementation with a lower incidence of side effects. However, always remember that supplementation in any form can not replace the benefits of a balanced and nutritious diet that includes a variety of foods!

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