Why do I need to have so much blood taken at my first appointment with the midwife?

Why blood tests are so important at your first midwifery appointment

5 things to know about blood tests in pregnancy

1. You will be offered blood tests in pregnancy to test for things that, if treated, will make it more likely that you have a healthy pregnancy and baby, and reduce the risk of complications.
2. The first tests you will be offered will be when you book the pregnancy with the midwife. 
3. Although it looks like loads of blood, it is less than it looks. Each tube is between 0.5-1 teaspoons, that’s all.
4. You midwife will be in contact if there are any problems. Usually the result will be checked and discussed at the 16 week check.
5. You will be tested for a variety of things, including anaemia, some infections and blood group. You are also tested for one group of inherited disorders that can cause anaemia. You are not tested for absolutely everything.

Why is so much blood taken?

At your first full appointment with the midwife, you will be asked lots of questions about your personal and family history. This is to assess your risks during pregnancy. The midwife will also offer you several blood tests. These are to screen for problems that we know are important in pregnancy, so that action can be taken if needed. Some of the tests you might have heard of, but others are less well known. 

Which blood tests are actually done?

1. Full blood count – this is the blood test taken to look mainly for anaemia. It does this by looking for the amount of haemoglobin in the blood. It also looks are other parameters in the blood, the other main one being the number of platelets. Platelets are the small cells in the blood that are needed to form blood clots. Ferritin is also sometimes measured. This is a molecule that can indicate how much iron you have stored in your body.

• HbA1C – this is short for haemoglobin A1C. This is a test which can indicate type 2 Diabetes. If it is high, it shows that you have had higher levels of sugar (glucose) in the blood during the last 3 months. Not everyone will have this test. 

• Haemoglobinopathy screening – this is a test to look for inherited forms of anaemia. It screens for many different variations, but the main one is Sickle cell disease. This is commoner if you have origins in particular parts of the world, such as Africa. Not all hospitals test everyone for this – some hospitals limit the test to people from specific parts of the world. Others test everyone. 

• Infection screening – we know that there are several infections that can harm a baby. You will be offered tests for hepatitis B, Syphilis and HIV. 

• Blood group and antibody test – you will have your blood group tested so that the hospital have a record of which blood group you are, just in case you suffer bleeding in pregnancy. Also, if you are rhesus negative, most hospitals you will offer an additional test to see if your baby is rhesus positive or not. This is to find out if you need to be given an ‘anti-D’ injection later in the pregnancy. This test will also look for antibodies to different blood group molecules in your blood. This is important both for the pregnancy, as some women have antibodies that can cause problems for the baby and also it is important if blood transfusions need to be given at any point.

• Urine test – as well as blood tests, the midwife will as for a sample of urine. This can be unpleasant and uncomfortable to collect but it is really important to follow the instructions for collecting a clean sample. The urine will be tested there and then in the clinic, mainly to measure the level of protein and glucose (sugar) in it, and also to see if there are any white cells present. These can sometimes indicate an infection. The sample will then be sent away to test for infection (a ‘UTI’) even if you have no symptoms. This is because some women have infections present in pregnancy with minimal or even no symptoms.