Elsevier

Seminars in Hematology

Volume 52, Issue 4, October 2015, Pages 339-347
Seminars in Hematology

Iron Deficiency Anemia in Pregnancy

https://doi.org/10.1053/j.seminhematol.2015.07.003Get rights and content

Anemia is a common problem in obstetrics and perinatal care. Any hemoglobin below 10.5 g/dL can be regarded as true anemia regardless of gestational age. Reasons for anemia in pregnancy are mainly nutritional deficiencies, parasitic and bacterial diseases, and inborn red blood cell disorders such as thalassemias. The main cause of anemia in obstetrics is iron deficiency, which has a worldwide prevalence between estimated 20%–80% and consists of a primarily female population. Stages of iron deficiency are depletion of iron stores, iron-deficient erythropoiesis without anemia, and iron deficiency anemia, the most pronounced form of iron deficiency. Pregnancy anemia can be aggravated by various conditions such as uterine or placental bleedings, gastrointestinal bleedings, and peripartum blood loss. In addition to the general consequences of anemia, there are specific risks during pregnancy for the mother and the fetus such as intrauterine growth retardation, prematurity, feto-placental miss ratio, and higher risk for peripartum blood transfusion. Besides the importance of prophylaxis of iron deficiency, the main therapy options for the treatment of pregnancy anemia are oral iron and intravenous iron preparations.

Section snippets

Anemia in General and Iron-Deficiency Anemia in Particular

Published rates of the prevalence of anemia during pregnancy in developing countries range from 53%–61% for Africa, 44%–53% for South-East Asia, and 17%–31% for Europe and North America.1 It is assumed that iron and folate deficiency are the most common etiological factors responsible for this situation.2, 3 Anemia of pregnancy is not merely common in these countries, it is also frequently severe. It is estimated that 20% of pregnant women have hemoglobin levels of <8 g/dL, and that between 2%

Iron Needs in Pregnancy

During pregnancy, the average total iron requirement has been estimated to be approximately 1,200 mg for an average weight of 55 kg in a pregnant woman. The iron is used mainly for the increase in maternal erythrocyte mass (450 mg), placenta (90–100 mg), fetus (250–300 mg) general losses (200–250 mg), and a blood loss at delivery corresponding to 150 mg iron (300–500 mL blood loss). Around 40% of women begin their pregnancy with low or absent iron stores (serum ferritin <30 μg/L) and up to 90%

General Consequences of Anemia

Any disorder that leads to anemia represents an increased risk of an abnormal course of pregnancy and greater maternal and infant morbidity and mortality. According to World Health Organization (WHO) data, anemia is associated with 40% of maternal deaths worldwide.4

The clinical consequences of anemia of pregnancy are closely associated with the cause of the anemia. In this respect, it is difficult to determine whether the maternal and infant risks result from the anemia alone, or whether they

Maternal Risks

The maternal risks of iron-deficiency anemia are listed in Table 2. It is known that iron deficiency influences a whole series of body functions, such as physical and mental performance, enzymatic functions (eg, those of the respiratory chain), thermoregulation, muscular functions, the immune response, and neurological functions.5, 6 Only a few of these potential effects have been specifically investigated in iron-deficiency anemia. In general, iron-deficiency anemia leads to numerous symptoms

Diagnosing Anemia During Pregnancy

The pathogenesis of anemia is highly variable. As a result, a diagnosis based on hemoglobin levels alone is generally insufficient. In all cases, therefore, it is necessary to determine the underlying reason for the reduced hemoglobin production, whether by taking a targeted medical history, carrying out a clinical assessment or by means of further investigations done in addition to the basic diagnostic tests.

Prevention of Iron Deficiency

Most guidelines recommend an increase in iron consumption by about 15 mg/d (to ~30 mg/d), an amount readily met by most prenatal vitamin formulations. This is adequate supplementation for non-anemic and non–iron-deficient women. In a 2012 systematic review, daily iron supplementation reduced the risk of maternal anemia at term by 70% and iron deficiency at term by 57%. According to WHO guidelines, daily oral iron and folic acid supplementation is recommended as part of the antenatal care to

Conclusions

Iron-deficiency anemia is the most frequent form of anemia in pregnancy and can have serious consequences for both the mother and fetus. The majority of women do not have adequate iron stores to meet the dramatic increase in requirements during the second and third trimester of pregnancy. Currently, the main interventions are oral iron and blood transfusions. However, there is increasing evidence that intravenous iron is more effective, provides more rapid hemoglobin correction, corrects iron

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    Conflicts of interest: C. Breymann is a medical consultant for Vifor International company in the field of iron therapy in OBGYN. No funding or financial support or scientific support was received for this review.

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