Anaemia during pregnancy

Reviewed by Dr Philip Owen, consultant obstetrician and gynaecologist and Dr Patrick Davey, cardiologist

What is anaemia?

Anaemia is a lack of red blood cells, which can lead to a lack of oxygen-carrying ability, causing unusual tiredness.

The deficiency occurs either through the reduced production or an increased loss of red blood cells. These cells are manufactured in the bone marrow and have a life expectancy of approximately four months.

To produce red blood cells, the body needs (among other things) iron, vitamin B12 and folic acid. If there is a lack of one or more of these ingredients, anaemia will develop.

What are red blood cells?

Red blood cells are the cells that circulate in the blood plasma (fluid) and give blood its red colour. Through its pumping action, the heart propels the blood around the body through the arteries. The red blood cells obtain oxygen in the lungs and carry it to all the body's cells.

The cells use the oxygen to fuel the combustion (burning) of sugar and fat, which produces the body's energy.

During this process, called oxidation, carbon dioxide is created as a waste product. It binds itself to the red blood cells that have delivered their load of oxygen. The carbon dioxide is then transported via the blood in the veins back to the lungs where it is exchanged for fresh oxygen by breathing.

Causes of anaemia during pregnancy

Women often become anaemic during pregnancy because the demand for iron and other vitamins is increased. The mother must increase her production of red blood cells and, in addition, the foetus and placenta need their own supply of iron, which can only be obtained from the mother.

In order to have enough red blood cells for the foetus, the body starts to produce more red blood cells and plasma. It has been calculated that the blood volume increases approximately 50 per cent during the pregnancy, although the plasma amount is disproportionately greater. This causes a dilution of the blood, making the haemoglobin concentration fall. This is a normal process, with the haemoglobin concentration at its lowest between weeks 25 and 30. The pregnant woman may need additional iron supplementation, and a blood test called serum ferritin is the best way of monitoring this.

Other causes include:

a diet low in iron. Vegetarians, and dieters in particular, should make sure their diet provides them with enough iron.

lack of folic acid in the diet, or more rarely, a lack of vitamin B12.

loss of blood due to bleeding from haemorrhoids (piles) or stomach ulcers.

anaemia is more common in women who have pregnancies close together and also in women carrying twins or triplets.

What are the symptoms of anaemia during pregnancy?

If the woman is otherwise healthy, she will rarely have any symptoms of anaemia unless her haemoglobin (red pigment) is below 8g/dl.

The first symptoms will be tiredness and paleness.

Palpitations - the awareness of the heartbeat, breathlessness and dizziness can occur, though they are unusual.

If the anaemia is severe (less than 6g of haemoglobin per decilitre of blood), it may cause chest pain (angina) or headaches.

What can be done to avoid anaemia during pregnancy?

Be sure to get a varied diet.

If planning a pregnancy, talk to a doctor or midwife about food and supplements - if possible, before becoming pregnant.

Good sources of iron are beef, wholemeal bread and cereals, eggs, spinach and dried fruit.

Supplementing the diet with iron, vitamins and especially folic acid. Taking 400 micrograms folic acid when pregnant is important to reduce the risk of having child with spina bifida. A doctor may advise taking combined iron and folic acid supplements.

To absorb the maximum amount of iron from the diet, it will help to also eat a diet rich in vitamin C. Raw vegetables, potatoes, lemon, lime and oranges are all good sources of vitamin C.

Foods rich in folic acid include beans, muesli, broccoli, beef, Brussels sprouts and asparagus.

A pregnant woman should take notice of her body's signals and consult a doctor if any symptoms occur.

It is now routine to recommend to women planning a pregnancy to take a folic acid supplement for the first 12 weeks of pregnancy and preferably starting before conception. This reduces the risk of spinal cord defects (spina bifida) developing in the foetus.

How does a doctor diagnose anaemia during pregnancy?

Apart from the clinical symptoms, anaemia is usually detected during antenatal screening. Blood tests are usually done at the first consultation, and again in the second half of pregnancy.

A description of the red blood cells - their different form and colour will be included in the result of the blood test.

In women of Afro-Caribbean or Mediterranean origin, additional tests are performed to screen for genetic causes of anaemia, namely sickle cell anaemia and thalassaemia.

Possible complications of anaemia

Difficulty in breathing, palpitations and angina.

Severe anaemia due to loss of blood after the delivery. If this occurs, then a woman may be advised to have a blood transfusion.

Go To Next Page>>



The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care or attention by a qualified practitioner. The materials in this web site cannot and should not be used as a basis for diagnosis or choice of treatment. Conditions for use



© Copyright 1998 - 2004 NetDoctor.co.uk - All rights reserved