Iron deficiency in pregnancy

By Dr Christian Kalwiba, Obstetrician Gynaecologist

by Tia

Iron is one of the most important nutrients for human beings. Not only is it a key player in red blood cell synthesis and erythrocytes production, but it also plays a role in multiple physiological processes including oxygen transport to different parts of the body, protein synthesis and cellular respiration.

Pregnant women are especially predisposed to iron deficiency because of the different physiological changes happening during pregnancy.

Firstly, the number of red blood cells in the body and progressive blood dilution due to increased plasma leads to a decrease in iron concentration. This process happens from conception until week 35 in pregnancy.

Secondly, iron deficiency is ascribed to the increasing demand in pregnancy due to fetal development and growth, with the placenta requiring high iron for the exchange between mother and fetus. The demand is greater in a multiple than a singleton pregnancy.

In addition to the above normal physiological changes that predispose pregnant women to develop iron deficiency in pregnancy, there are other risk factors which further increase the chance of this condition. These include having two pregnancies close to each other, being pregnant with more than one baby, iron-poor nutrition, nausea and vomiting due to severe morning sickness, heavy pre-pregnancy menstrual flow, and anemia before pregnancy.

A lack of iron will lead to either one of two different medical conditions:

1. Iron deficiency with anemia, commonly known as iron deficiency anemia, which was for a long time considered to be the only manifestation of lack of iron; or

2. Iron deficiency without anemia, also called iron deficiency.

These two conditions are not synonymous. In a nutshell, iron deficiency is a state of negative balance where the iron supply does not meet the demand, whereas iron deficiency anemia constitutes a low hemoglobin level due to a lack of iron resulting in poor production of red blood cells. Laboratory tests help differentiate between these two conditions.

Symptoms of iron deficiency or iron deficiency anemia
The symptoms of both iron deficiency and iron deficiency anemia are fatigue, weakness, dizziness, headache and craving or chewing ice (Pica).

You will notice that these symptoms are also present in pregnancies with iron sufficiency. Even though pregnant women are screened for anemia in pregnancy worldwide, I believe that we should also add the screening to our routine blood test in pregnancy.

Assessing the iron levels at that stage will help us make an early diagnosis of iron deficiency or iron deficiency anemia. In this way, these conditions can be treated before the unborn baby is negatively impacted.

It is crucial to maintain an iron-sufficient state during the entire pregnancy to avoid short- and long-term effects on the unborn baby. The immediate consequences of lack of iron are the increased risk of a pregnant woman having a small baby, and high-risk prematurity (delivery of baby before 37 weeks).

Lack of iron is also associated with postpartum depression and a low iron level in the newborn, in other words the newborn will also suffer from iron deficiency.

Recent research has revealed that low maternal iron in the last trimester of pregnancy results in altered brain structure and affects neurocognitive function. Even if the deficiency is later corrected in the infant, low neonatal iron status results in reduced recognition memory performance at age 3-4 years. According to some publications, iron deficiency may also be associated with depression, anxiety, and social dysfunction later in life.

Preventing iron deficiency
Lack of iron during pregnancy can be prevented by different means such as good nutrition, including the consumption of iron-rich food like lean red meat, poultry and fish.

Prenatal vitamin supplements all contain iron, and this can be used as a preventative measure in women where iron levels are not yet low, or as curative measures where the iron concentration in the blood is below the lower limit of normal. It is recommended that, to prevent iron deficiency, all pregnant women should receive prenatal vitamins containing iron.

In some circumstances, depending on the severity of the iron deficiency or if the pregnant woman is unable to take iron tables orally or has severe nausea and vomiting, intravenous iron (iron in the drip) can be given in order to the correct the iron levels. This, however, can only be done in hospital.

Dr Christian Kalwiba
Dr Christian Kalwiba is a highly skilled obstetrician and gynaecologist who delivers comprehensive medical care, and ensures his patients are well-informed about their medical condition(s). He is particularly interested in gynaecology and promotes a natural, vaginal birth.
Address: Kingsbury Medical Suites, Wilderness Road, Claremont, 7700
Tel: +27 (0)21 745 6565 | Email:

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