Anaemia in pregnancy
Some women become anaemic when they are pregnant, which means they have too few red blood cells in their body. Anaemia can make you even more tired when you’re pregnant, but there are ways to manage it.
What are red blood cells?
Red blood cells are cells in your blood. Their main role is to carry oxygen from your heart to the rest of your body — your brain, your muscles, your skin, your kidneys and everywhere else. Red blood cells are produced in bone marrow. They contain a protein known as haemoglobin, which is vital for carrying oxygen.
We need enough iron, vitamin B12 and folate to produce all the haemoglobin we need.
What is anaemia?
When you have anaemia, your blood doesn’t have enough healthy red blood cells or haemoglobin to carry oxygen around your body and to your baby.
Mild anaemia is common in pregnancy. If you have mild anaemia, you will feel a little tired.
If you have severe anaemia, you may feel like you are constantly out of breath and may feel weak, dizzy, irritable and find it hard to concentrate. Your heart will often be racing.
Why do pregnant women become anaemic?
Your body changes during pregnancy to look after your growing baby. Your body needs to make more blood when you are pregnant. The average woman will have about 5L of blood when not pregnant, compared to 7 to 8L of blood near the end of the pregnancy.
Making the extra blood cells requires plenty of iron, vitamin B12 and folate to make all the extra haemoglobin needed. Iron deficiency is the main cause of anaemia during pregnancy. You need 3 times as much iron when you are pregnant than when you are not, and your iron requirements increase throughout the pregnancy.
Unfortunately, iron is hard to absorb, which makes haemoglobin hard to make. So many women become anaemic during pregnancy unless they take iron supplements.
Anaemia in pregnancy can also be caused by lack of folate and vitamin B12, bleeding, or having a condition such as pre-eclampsia or sickle cell disease.
What are the tests for anaemia?
You would usually have a blood test around the time you first see a doctor or midwife about your pregnancy and again at 28 weeks to check your full blood count. Your haemoglobin level will be checked as part of this test. You might have further tests if your haemoglobin is low for your stage of pregnancy.
What are the risks if I am anaemic while pregnant?
Being severely anaemic can affect your heart and make you more unwell if you lose a lot of blood during the birth.
How can anaemia in pregnancy be avoided?
There are 3 good ways to avoid becoming anaemic while pregnant:
- Start your pregnancy in good health.
- Eat well while pregnant.
- Take iron supplements if needed.
Starting pregnancy in good health
If you are thinking about becoming pregnant, you should see your doctor and get a check-up. At this time, you will get advice about anaemia and other conditions, and particularly about taking iodine and folate supplements.
Women are advised to take a folic acid supplement for at least a month before becoming pregnant and continue this for at least the first 3 months. This will decrease the risk of neural tube defects such as spina bifida. The standard dose is 0.5mg of folic acid per day, but the dose may be higher for women who have diabetes, epilepsy, are overweight or have had a child with a neural tube defect. This should be discussed with a doctor.
It is also recommended to consume 150mcg Iodine through supplements as well as obtaining iodine from a healthy diet. Iodine is used in the body to produce thyroid hormones. It is essential for the baby’s development and pregnant women need more iodine that the average person.
Eating well while pregnant
Eating a healthy diet protects against anaemia. Iron is found in meats, iron fortified breads and cereals, eggs, spinach and dried fruit. Vitamin B12 is found in meat, fish, shellfish, eggs and dairy products. High levels of folate are found in green leafy vegetables, beans, muesli, broccoli, beef, brussels sprouts and asparagus Eating a diet rich in these foods will help prevent anaemia.
Women who are vegetarian can replace animal foods with lentils, beans, tofu, eggs and soy milk. Advice from a doctor or dietitian is suggested, and vitamin B12 supplements may be recommended.
Eating plenty of citrus fruit, and avoiding tea and coffee with or soon after meals, may help you absorb the iron in your food, and may help prevent anaemia.
All women will be advised to take iodine and folate supplements when planning a pregnancy and for the first 3 months, as well as eating foods rich in iodine and folate. Many women will be advised to take iron supplements if they are iron deficient or are at risk of becoming iron deficient. Vegetarians and vegans may be advised to take vitamin B12 supplements. If you are advised to take supplements, talk to your doctor about the best ways to take them, and how to avoid any possible side effects.
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Last reviewed: November 2020