Why Do I Need More Iron Now?

Growing a baby is a unique and demanding experience. Although your body is designed to do it, you need to make sure you have all the nutrients required for the job. Iron is involved in many processes in your body; it is needed to help carry oxygen around the body; make energy in your muscles; to help you concentrate and to help you fight off infections.1–3 But, when you are pregnant you need iron to do all of this and to develop a healthy placenta, to support the growth of your baby and protect you against any blood loss during delivery.4

Iron and You

Iron is important, not only to keep your body working well, but for all the changes that start as soon as you are pregnant.

The Placenta

The placenta is a new organ that grows during pregnancy. Oxygen and nutrients from your blood travel through the placenta and into the umbilical cord to be delivered to your baby. Waste products that your baby makes travel back through the umbilical cord and across the placenta for your body to get rid of.5 All of this transfer of nutrients and waste occurs through blood in blood vessels, and iron is needed for development of this blood.1,6

Extra Blood

During your pregnancy you will almost double the amount of blood going around your body. This extra blood is important for taking nutrients to the placenta and collecting the waste from your baby. Your blood is made up of something called plasma and red blood cells. You will need to increase the number of red blood cells you have by 35%, and to do this your body needs iron.7 On top of this you also have to provide iron for the blood in your baby’s body!


Iron and a Healthy Pregnancy

For a successful pregnancy it is important that you maintain good iron levels.8 Having iron deficiency anaemia during pregnancy can cause your baby to be born early (premature) or be small (low birth weight).8

There are some factors that may put you at a higher risk of becoming iron deficient or developing iron deficiency anaemia:

  • If you had low iron levels before you were pregnant
  • If you have other children, especially if they are close in age
  • If you are having twins, or more4

If you have iron deficiency anaemia whilst you are pregnant, you are likely to still have low haemoglobin levels after giving birth, and less able to cope with any blood loss during delivery.4 Having low haemoglobin levels after the birth can increase your chance of getting postnatal depression,9 reduce the quality of your breastmilk10 and make it harder to look after your baby.11

To learn more about your iron needs after the birth of your baby, see our section on “delivery and early days”.

The amount of iron you need changes across the different trimesters of your pregnancy. In the first trimester you save some iron from your periods stopping, but during the second and third trimesters your need for iron increases.7 In fact, you will need to have 1.5 times as much iron in your diet than before you were pregnant.12

Luckily, your body is designed to get as much iron as it can from your food, and absorption of iron from your food changes along with your baby’s needs. By the time you are 30 weeks pregnant your body works to absorb almost 90% of the iron you eat – 3 times as much as at 8 weeks.7 You can also help your body adapt by eating an iron-rich diet. Please note that it is important to ask your doctor or midwife about the best foods to eat while you are pregnant since some foods, such as liver13 or certain types of fish,14  should be avoided during pregnancy.

Iron and a Healthy Baby

Iron is needed for all organs to work properly, but especially when they are growing.15 Your baby uses the iron it gets from you to make red blood cells first. If there is not enough iron then other parts cannot grow as well. The heart, muscles and brain of your developing baby can all be left without enough iron.4 The baby’s immune system (which helps them fight infections once they are born) can also be affected.15 Iron is so important for the development of a healthy brain that children whose mothers had low iron can have a lower IQ.4

It is not just for growth in the womb that your baby needs iron – iron is also crucial for it to grow after birth.15 Because breast milk doesn’t have much iron in it,16 your baby uses iron stored before birth to grow. A healthy, full-term baby will have enough iron to keep it growing normally until it is 4-6 months old.16 After this they begin to get iron from the solid food they eat, or perhaps from formula. To learn more about iron and your baby after birth see our section on “iron and your baby”.

Your baby’s iron stores can be affected even if your iron levels are low but you have not yet developed iron deficiency anaemia,15 so make sure you stick to a diet high in iron

Unnecessary iron supplementation is not healthy for you or your baby, so always speak to your doctor before adding a supplement to your diet, especially if you have no signs of iron deficiency.