Why is Iron Important for Women Pregnant with Twins?

Congratulations you’ve just found out you’re having twins! 

This is an exciting time but for some women it can lead to feelings of isolation and confusion.

When you’re pregnant with twins or more you have different nutritional requirements than women pregnant with one baby. If you’ve tried to find out what the nutritional recommendations are for a healthy twin pregnancy you’ve probably been left with more questions than answers. 

Unfortunately there’s a real shortage of research on twin pregnancies to give clear recommendations for the various macro and micro nutrients. But I’m here to give you some clarity, and save a lot of time that you might spend searching the internet for answers. 

One of the key nutrients, for a healthy twin pregnancy, is iron. 

If you’re pregnant with multiples you’re more likely to develop iron deficiency which can increase your risk of preterm labour and giving birth to small babies. 

What is Iron?

Iron is an important dietary mineral. It’s needed for maintaining many body functions, including the production of haemoglobin. Haemoglobin is the molecule in your blood that is responsible for carrying oxygen which is essential for providing energy for day to day activities.

Iron from the food you eat is absorbed into the body by the cells of your gastrointestinal tract. The body only absorbs a small fraction of the iron you eat. Iron is then released into the blood stream, where a protein called transferritin attaches to it and delivers the iron to the liver. Iron is stored in the liver as ferritin and released as needed to make new red blood cells in the bone marrow.

What food contains iron?

There are 2 types of iron in food: haem and non-haem. Haem iron, found in meat, chicken and seafood, is absorbed better than non-haem iron, which is found in eggs and some plant foods.

Good sources of haem iron

Liver (avoid if pregnant)

Red meat, beef, lamb, kangaroo

Fish

Chicken

Good sources of non-haem iron

Eggs

Legumes

Nuts and seeds

Tofu

Wholegrain cereals such as oats, brown rice, wholegrain bread

Some vegetables such as broccoli and spinach

Dried apricots

What is the role of iron in pregnancy?

During pregnancy, a woman’s blood volume increases, particularly during the second and third trimester. This increase in blood volume requires more iron to drive oxygen for mum and for the growing baby and placenta. The recommended daily intake of iron during pregnancy is 27mg per day, which is 9mg more than a non-pregnant woman of child bearing age.

In pregnancy iron plays a role in early brain growth and function. Iron deficiency anaemia significantly increases the risk of going into labour early and giving birth to a small baby.

Also babies born to mothers who have iron deficiency anaemia are more likely to be born with anaemia. 

What if I’m pregnant with twins or more?

When you’re pregnant with multiples, more babies means higher iron requirements, and your blood volume increases greater than if you were having only one baby. It’s estimated that your iron requirement is 1.8 times higher than in a singleton pregnancy. [1]

Women pregnant with multiples are 2.4- 4 times more likely to develop iron deficiency anaemia, compared to women with only one baby. [2]

What are the stages and symptoms of iron-deficiency?

If you don’t have enough iron in your diet to meet the needs of you and your babies your body’s iron stores get lower over time.  This can cause iron depletion, where there is usually no symptoms, then iron deficiency and eventually iron deficiency anaemia. 

Symptoms of iron-deficiency and iron deficiency anaemia might include

• Being pale
• Unexplained fatigue
• Low energy
• Shortness of breath
• Rapid heartbeat
• Headaches
• Pounding or whooshing  in the ears
• Poor concentration

How is Iron – Deficiency diagnosed?

Low energy, shortness of breath and poor concentration are pretty vague symptoms and might be how you feel everyday because, let’s face it, you’re pregnant with twins. If you have iron depletion you are not likely have any symptoms. To detect iron depletion early and to prevent iron deficiency when you’re pregnant with twins it’s important to have blood tests to check your iron status early and regularly throughout your pregnancy.

Can I get enough Iron from food?

Eating a diet high in iron can help prevent iron deficiency in most women however during pregnancy, especially if you’re expecting multiples you will most likely require a supplement to help meet your higher requirements.[3] Most prenatal supplements contain some iron which may be enough to meet your needs.

If I’m pregnant with twins or more should I take an iron supplement to prevent iron deficiency?

Iron supplements are handy to help reach your required daily iron requirements when it’s challenging to do this through food alone. However, common reported side effects of iron supplements are constipation and nausea. The higher the supplement dose the more likely the side effect. It’s a good idea to try to optimise your diet to get as much iron as you can and then take a smaller dose of iron supplement.

Also, you can have too much. Studies have recently reported that unnecessary iron supplementation, especially early in pregnancy, may increase your risk of pregnancy hypertension, pre-eclampsia and gestational diabetes. [4][5]

Your iron supplement should be carefully calculated by your doctor or pregnancy dietitian and let them know if you’re having any side effects.

Iron and a twin pregnancy in a nutshell

If you’re pregnant with twins or more you have higher iron requirements and a greater chance of developing iron deficiency. You will have your iron status tested regularly throughout your pregnancy. It’s a good idea to try to eat a nutritious diet high in iron and you will probably require an iron supplement to help meet your needs and those of your growing babies.