The blood that is taken at your booking visit may be tested for:
- Blood group and rhesus factor
- Blood sugar
- Haemoglobin level
- Hepatitis B. This is a viral infection that affects your liver and is transmitted to the baby. If you test positive your baby will be treated with a course of immunisations starting at birth.
- Rubella (German measles). If you are not immune, you are advised to avoid contact with anyone who may have rubella; you’ll be offered an immunisation injection after your baby is born.
- Thalassaemeia. This disorder primarily affects people from Mediterranean, Asian and Middle Eastern backgrounds.
Other pregnancy blood tests
According to your medical and family history, you may also be offered other screening tests, for example, for cystic fibrosis or sickle cell disorder. Sickle cell disorder primarily affects people from African, Caribbean or Asian backgrounds and some from Middle Eastern or Mediterranean backgrounds. Your midwife will ask if you or your partner, or either of your families, are from a high risk area. This is because these disorders could be passed on to your children. If you are tested, you’ll be given a card showing whether you have either disorder or not. If you are found to have a disorder, you will be referred for specialist counselling; your partner will also be offered screening for the disorder.
You should be told the results even if everything’s fine. All this information is held in your file – and should be written in your records which you are carrying.
Most maternity units in England now have a policy of offering a confidential HIV test to all pregnant women. You may decline this offer if you wish. If your HIV status is known to be positive, there are treatments to reduce the risk of passing this onto your baby. You will be cared for by a specialist team and offered counselling before and after the test.
Your rhesus status matters when you’re pregnant because if you’re rhesus-negative and the baby’s father is rhesus-positive, your baby could be rhesus-positive. That means your baby’s blood could be different from yours. During pregnancy, a few of your baby’s red blood cells will pass into your circulation. Your immune system recognises these cells as different from yours and forms antibodies against them. When these pass back into your baby’s circulation, they can destroy his red blood cells. Babies born with Rhesus disease used to be very ill, but now they can be protected while still in the womb.
If you are rhesus-negative, you will be told, and you’ll need extra care. you may be offered an injection of rhesus immunoglobulin (anti-D) at the 28th and 34th weeks of your pregnancy. This will coat any of the baby’s cells that may be in your blood stream and destroy these ‘invaders’ before your immune system responds to them. You will also have some extra blood tests to see if you have developed any rhesus antibodies. This rarely happens, but if it does, you will be carefully monitored.
If you have any ‘trauma,’ such as an accident, amniocentesis or CVS, you will need an injection of anti-D immunoglobulin.