The importance of iron during pregnancy

Physiologically, pregnant women have a higher iron requirement, which begins shortly after conception and increases progressively throughout pregnancy. During pregnancy, the demand for iron is almost multiplied tenfold [3]!

Some scientists argue that it is not possible to maintain the iron status of a pregnant woman through normal dietary practices and that iron intake additional supplement to prevent deficiency is necessary [4]. A food supplement for pregnant women iron-based supplement may help in these cases, but is not suitable for everyone. 

A study of pregnant women in France showed that 33% of them suffered from anaemia. The prevalence of anaemia increased with the duration of pregnancy, rising from 25% in women in their first trimester, to 32% in the second trimester and 57% in the third trimester [5].

An adequate iron intake is essential to meet the increased oxygen consumption demands of pregnancy. The foetal brain is particularly oxygen-hungry, accounting for 60% of the foetus's total oxygen consumption [6]. 

For example, each additional gram of haemoglobin synthesised by the mother requires an additional intake of 3.46 mg of elemental iron. Furthermore, the foetus needs iron for its own metabolic and oxygenation needs, as well as to build up its relatively large iron stores, which will be drawn upon during the first six months of postnatal life [7]. Children born with lower foetal iron stores have lower iron reserves at 9 months of age and a higher risk of postnatal iron deficiency [8].

To improve the iron status of the newborn, studies show that delayed cord clamping improves iron status and haemoglobin levels at 2 months [9]. To find out more about the benefits of delayed cord clamping, have a look at our article on the subject. 

Iron deficiency results from an insufficient dietary intake of absorbable iron to meet the increased demands of pregnancy (to nourish the growing foetus and increase the mother's red blood cell mass) and/or iron loss through blood loss [10].

In cases of mild iron deficiency in the mother, iron is prioritised for the foetus. However, in cases of moderate or severe iron deficiency, the entire maternal-placental-foetal unit becomes iron-deficient, with significant short- and long-term consequences for the foetus.

These consequences also occur in the foetuses of iron-sufficient mothers who nonetheless experience pregnancy conditions that compromise iron delivery to the foetus: hypertension, smoking, diabetes and multiple pregnancies [11].

Risks for pregnancy outcomes

During the first trimester, a low haemoglobin concentration is significantly associated with low birth weight and premature birth [12].

Moderate to severe maternal anaemia is associated with an increased risk of small-for-gestational-age babies [13].

Please note: excess iron has also been associated with adverse effects on pregnancy outcomes. Care should be taken with self-supplementation, particularly if you are not at risk of deficiency, as this can have consequences. You can find out your iron status with a simple blood test.

Risks for the newborn

The immediate risk concerns the development of the foetal brain. Low iron intake in the mother during the third trimester leads to changes in the structure of the neonatal brain, including alterations to grey matter [14].

Furthermore, a study of nearly 300 children observed that low iron levels during pregnancy are associated with neurodevelopmental problems in children at age 5 [15].

Iron deficiency during infancy and childhood is associated with slower processing speed, poorer motor function and social dysfunction. It is also associated with significant long-term neuromorbidities, including depression and anxiety in adulthood [16].

Iron in food

The bioavailability of dietary iron has been estimated at an average of 14–18% for mixed diets and 5–12% for vegetarian diets [17].

There are two types of dietary iron: non-haem iron, found in both plant foods and animal tissues, and haem iron, which comes from haemoglobin and myoglobin in animal-derived foods. Haem iron is better absorbed by the body than non-haem iron, which means that vegetarian or vegan individuals are more likely to be iron-deficient.

A few iron-rich foods: 
Liver (during pregnancy, be mindful of liver due to its vitamin A content — you can consume 40g of cod, chicken or rabbit liver, but avoid calf, heifer, turkey and lamb liver); for example, poultry liver contains 12mg of iron per 100g 
Red meat (choose quality meat, organic where possible)
Lamb contains 12.4mg of iron per 100g
Certain shellfish (which must be eaten cooked during pregnancy) — for example, cooked clams contain 10mg of iron per 100g.
Seeds (sesame: 15mg of iron per 100g, flaxseed: 10mg, chia: 8mg)
Vegetables contain an average of 7mg of iron per 100g (lentils, beans, broad beans)

How can iron absorption be improved?

Certain molecules or nutrients inhibit iron absorption. For example, phytates (found notably in coffee) reduce iron absorption, and this effect increases with higher phytate content [18].

Polyphenols can also affect iron absorption, though this depends on the type and dietary source. For example, those found in black tea inhibit iron absorption more strongly than herbal teas [19], and chilli inhibits iron absorption but turmeric does not — even though it contains more polyphenols [20]!

Animal proteins, such as milk proteins, egg proteins and albumin, inhibit the absorption of non-haem iron [21].

Conversely, vitamin C improves iron absorption and can overcome the negative effect of all inhibitors on iron absorption [22]. Its influence may be less pronounced in meals with high iron availability — those containing meat, fish or poultry [23].

What about iron supplements?

The form of iron in supplements affects iron absorption and its impact on the gut. The main drawback of traditional ferrous salts is the frequency of gastrointestinal side effects such as nausea, vomiting, abdominal cramps and constipation.

It appears that iron bisglycinate is the best form of iron for supplementation. Its bioavailability (the ability of a nutrient to be absorbed through the intestinal mucosa and used effectively) is 90.9% [24]. Studies, particularly in pregnant women, show that it increases iron levels more effectively and without side effects compared with other forms of iron [25][26].

For example, a study showed that supplementation with 15mg of iron bisglycinate compared with 40mg of ferrous sulphate was more effective at improving iron status in a group of 150 pregnant women [27]. Iron depletion was found in 30.8% of women treated with iron bisglycinate, compared with 54.5% of women who consumed ferrous sulphate.

Bonus: the iron provided in supplements does not need to be combined with vitamin C to improve absorption [28]! Do bear in mind, however, that if you are taking a pregnancy vitamin containing zinc or calcium, it is advisable to space out your iron intake for optimal absorption. 

However, iron supplementation during pregnancy should not be taken blindly. It is important for pregnant women to know their iron status during pregnancy. For mothers who need to build up their iron stores, the amount required can vary considerably from one person to another. For this status to be properly assessed, blood tests are necessary and require rigorous interpretation.

Our iron-rich products

Iron Mama, our iron supplement for pregnant women, covers 100% of the recommended daily intake of iron in just 1 capsule. Say goodbye to the discomfort associated with iron capsules — with our Ferrochel™ iron bisglycinate, our capsules combine optimal absorption with digestive comfort. It can be taken in addition to our pregnancy supplement, which contains no iron, allowing you to supplement only according to your individual needs. 

Our pregnancy snack Croquantissime contains 7mg of iron bisglycinate, covering 50% of the recommended daily intake of iron! 
Our Granochoc granola also contains 7mg of iron bisglycinate per 100g. 

Women are particularly at risk of iron deficiency. Iron is important throughout all stages of life, especially during pregnancy to ensure an optimal iron status for the foetus.

There are many dietary sources of iron. Iron from animal-based foods is better absorbed by the body. Consuming vitamin C alongside iron-rich foods (particularly those that are not of animal origin) helps to improve its absorption.

When it comes to iron supplements, pay close attention to the form — not all are equal! Some are less well absorbed by the body and can cause gastrointestinal issues. Iron bisglycinate is a good choice.

Be careful not to self-supplement — food supplements are not without risk; they can interact with other supplements, foods and medications, or may not be suited to your personal situation, not to mention that choosing the right ones and adjusting dosages requires expertise. It is therefore advisable to seek guidance from a healthcare practitioner specialising in nutrition (such as a naturopath or nutritional therapist).