Is Routine Iron Supplementation Necessary in Pregnant Women With High Hemoglobin?

Iron supplementation during pregnancy is an important component in prenatal care to prevent anemia. During pregnancy increased plasma volume exceeded increase in red cell volume which causes dilution, and reduction in the concentration of hemoglobin. It has been found that hemoglobin levels can fall from the average of 12.5-13.0 g/dL to about 11.0-11.5 g/dL. According to the WHO, more than 40% of pregnant women suffer from anemia that is caused by iron deficiency about half the time, thus 30-60 mg of elemental iron supplementation is recommended for pregnant women. However, extremely high iron levels in pregnant women can adversely affect the birth outcome. Because of this it seems logical to say that iron supplementation is unnecessary in women who have high hemoglobin levels. This study examined the effects of iron supplementation on iron status markers in pregnant women with high hemoglobin.

The trial was randomized, double-blind, and placebo controlled. The population contained 86 pregnant women with Hemoglobin > 13.2 g/dL and ferritin > 15 μg/l in the 16th – 20th week of pregnancy. From their 20th week of pregnancy to the end, the experimental group were given 1 ferrous sulfate tablet with 50 mg of elemental iron daily, and the control group received a placebo. Hemoglobin and ferritin levels were evaluated at 37 to 39 weeks of pregnancy and after delivery the baby’s birth weight was measured. However 22 women ended up dropping out of the trial due to various reasons, so the date for 64 women were used in conclusions.

The mean hemoglobin concentration was 12.05 g/dL in the experimental group, and 11.94 g/dL in the placebo group which meant a significant difference in hemoglobin levels between the two groups. Though in comparing the birth weight of the babies, there was no significant difference between the two groups. By the end of pregnancy four women in both groups were anemic, however none had a hemoglobin level of less than 10 g/dL and the difference wasn’t significant between the supplement and placebo group. The researchers concluded that since not using iron supplementation didnt cause of anemia in women with hemoglobin concentrations greater than 13.2 g/dL during pregnancy the current recommendations made by WHO for women regarding iron supplementation during pregnancy should be followed. 

The researchers had the right idea in approach this study since it was very logical to think that since high iron levels affect birth outcomes negatively it made sense not to supply those women in their third trimester of pregnancy with high hemoglobin levels with additional iron supplements. There might be more evidence had the population of the overall study been larger, but given what it was those women who were given a placebo did end up having their hemoglobin levels drop to an average of 11.94 g/dL so maybe for those women who have high hemoglobin levels during pregnancy they should take iron supplements, but either towards the lower dosage end or just not take the supplements daily

Alizadeh L, Salehi L. Is Routine Iron Supplementation Necessary in Pregnant Women with High Hemoglobin? Iran Red Crescent Med J.  doi: 10.5812/ircmj.22761 (published 27 January 2016)