This is a question that comes up a lot in pregnancy. . .”What kind of iron supplements should I be taking? My practitioner says I’m anemic.” It turns out that a lot of practitioners mistakenly diagnose anemia based on old information and lack of understanding of the physiology of the pregnant woman.
This information from Dr. Michel Odent is very helpful:
Question for Dr. Michel Odent:
My hemoglobin is now 11.4 in week of gestation 19. A friend of mine has 7.8. Do I have to take ferrum? Is there a hemoglobin-limit?
Answer from M. Odent
It is probable that from now on your hemoglobin concentration will decrease. The placenta – which is ‘the advocate of the baby’ – will send you hormonal messages so that you dilute your blood in order to make it more fluid. Your blood volume will increase dramatically (up to 40% to 50%). Although you’ll still have the same amount of hemoglobin available, its concentration in your blood will be lower if the placenta is working well. The most authoritative published study on this issue involved more than 150 000 thousands births (Steer P, Alam MA, Wadsworth J, Welch A. Relation between maternal hemoglobin concentration and birth weight in different ethnic groups. BMJ 1995; 310: 389-91). According to this huge study a hemoglobin concentration between 8.5 and 9.5 during the second half of a pregnancy is associated with the best possible birth outcomes. Furthermore, when the hemoglobin concentration fails to fall below 10.5 there is an increased risk of low birth weight, premature birth and pre-eclampsia.
The regrettable consequence of misinterpreting this test is that, all over the world, millions of pregnant women are wrongly told that they are anemic and are given iron supplements. There is a tendency both to overlook the side effects of iron (constipation, diarrhea, heartburn, etc.) and to forget that iron inhibits the absorption of such an important growth factor as zinc. Furthermore, iron is a powerful oxidative substance that can exacerbate the production of free radicals. The disease pre-eclampsia is associated with an ‘oxidative stress’. Pregnant women need antioxidants (provided in particular by fruit and vegetable) rather than oxidative substances.
You should print the abstract of the study I mentioned (you’ll find it via PubMed, for example) in order to be in a position to discuss with practitioners who might tell you that you are anemic and that you need iron supplements. Don’t take iron supplements as long as your iron deficiency has not been proven by specific tests (ferritin in particular).
I cannot comment on the hemoglobin concentration of your friend, first because I don’t know if she is at the beginning or at the end of her pregnancy, and also because data regarding her lifestyle and data provided by a clinical exam should prevail upon the results of one laboratory test; this test should probably be repeated and completed, according to the context. (end of Dr. Odent’s comments)
Here is the link to the study he talks about:
This study is another piece of the puzzle that more women should know about:
University of Turin researchers have found that women who take iron
supplements during mid-pregnancy have a higher risk of gestational diabetes,
hypertension and metabolic syndrome. The study assessed iron
supplementation, along with other factors, for 1000 women-half with
gestational diabetes and half with normal glycemic levels-between 24 and 28
weeks gestation. Of the women studied, 212 were taking iron supplements,
mostly in the form of ferrous sulphate.
The researchers concluded, “Routine iron supplementation in pregnancy is a
matter of controversy and debate. The increasing reporting of harmful
effects for unnecessary iron supplementation should be carefully considered.
Further studies on larger cohorts are warranted to confirm these results,
but glucose values should at least be monitored in iron-supplemented
The full report can be accessed online at:
– American Journal of Obstetrics and Gynecology, 201(2): 158.e1-6, 2009