Studies show that 50 per cent of pregnant women do not have enough iron in their body. The iron demands during pregnancy and breast feeding are particularly evident due to the expanded red blood cell volume, demands of the developing baby and placenta and blood loss around the time of delivery.
The recommended daily intake (RDI) of iron for women aged 19 to 50 years is 18mg per day. For pregnant women, this RDI increases to 27mg per day; whilst for breastfeeding women, the RDI decreases to 9mg. This is thought to be due to the fact that the lactating mother cannot increase the iron levels in her milk by eating iron rich foods or taking supplements. Also menstruation does not normally resume until after 6 months of exclusive breastfeeding.
What is the role of iron in the body?
Iron is found in haemoglobin, a substance in the red blood cells that carries oxygen in the body.
Your body makes more blood when you are pregnant due to the demand from baby. It needs iron to make healthy blood.
A blood test that looks at haemoglobin (Hb) level is usually offered at the first antenatal visit and again at 26-28 weeks’ gestation.
Having low iron levels may result in anaemia. Any anaemia should be investigated and treated. Low iron will make you feel tired, have poor concentration and an increased risk of infection. Very low iron levels may cause low birth weight of the baby.
Iron in food
There are two forms of dietary iron: Iron from animal foods (called haem iron) and iron from plant foods (called non-haem iron). Haem iron is absorbed 10 times better than non-haem iron. It is found in animal foods that originally contained haemoglobin such as red meats, fish and poultry. Red meats are the best source of iron; the redder the meat, the higher the contents of iron.
This means beef, kangaroo and lamb are higher in iron than pork, chicken or fish. Red fleshed fish, such as tuna and salmon, are higher in iron than white fleshed fish.
Most non-haem iron is from plant sources:
- Wholegrain, iron-enriched breads and cereal foods.
- legumes (such as lentils, beans, chickpeas) and nuts
- green leafy vegetables (such as spinach, broccoli)
Our bodies are less efficient at absorbing non-haem iron than haem iron from animal foods. You will need to eat more of these foods if they are your only iron source.
To help your body absorb more iron from plant foods, eat it along with foods that have a high vitamin C content (fruits and vegetables).
For a detailed look at animal and plant-based iron-rich foods, head to the Nutrition Australia website: http://www.nutritionaustralia.org/national/resource/iron
How can I improve my iron intake?
While some foods can help our bodies absorb iron, others can prevent it. Tea, coffee, unprocessed bran and various mineral, herbal and other medications can block iron being taken up by the body.
Routine iron supplementation is not recommended in every pregnancy. Iron supplementation will generally be recommended for women at particular risk of iron deficiency. This includes when a blood test has confirmed that your levels are low, vegetarians or women with a multiple pregnancy.
Women with iron deficiency anaemia will need additional iron supplementation, containing at least 60mg of iron daily.
Women commonly experience constipation from taking iron tablets. You can manage constipation naturally by:
- eating more fruits, vegetables, wholegrains, legumes
- drinking more water
- remaining physically active
For more information on the recommended daily intake for iron requirement in pregnancy, head to the National Health and Medical Research Council – Nutrient Reference Values for Australia and New Zealand website: https://www.nrv.gov.au/nutrients/iron
Ways to improve your diet for adequate iron intake:
- Check that you are regularly eating animal sources of iron — the redder the better.
- Include wholegrain and iron fortified foods (e.g. cereals or wholemeal toast).
- Include vitamin C containing foods at meals (e.g. orange juice).
- Check to make sure you limit the iron blockers.
- Talk to your GP, midwife or obstetrician about taking iron tablets.
What to do if your iron levels are still low:
You should talk to your doctors or midwife to have your Haemoglobin (Hb) level checked during antenatal visit and any anaemia should be investigated and treated. Your doctor should consider iron studies if the haemoglobin is 105 g/L or less or red blood cells are microcytic (small); B12/folate levels if the red blood cells are macrocytic (big). Testing for Thalassaemia (haemoglobin electrophoresis) should also be considered where appropriate.