Blood Tests in Pregnancy

‘Booking bloods’ – routine antenatal tests offered to all women.

Blood group

It is important to know which blood group you have (A, B, O or AB) so that the correct blood can be given if needed.

Rhesus factor

Only one woman in six is Rhesus Negative. In certain circumstances these women can produce antibodies which may affect a second or subsequent babies. Because of this if You will also be advised to have this injection after any invasive procedures e.g. amniocentesis. Anti-D is also advised for Rhesus Negative women who give birth to a Rhesus Positive baby, to protect any future pregnancies.


Sometimes unexpected antibodies (foreign blood proteins) are present in the blood stream from a previous pregnancy or blood transfusion. In rare cases these can affect the developing baby.

Full blood count

This test examines blood cells and haemoglobin level (Hb). If the Hb is low it may be an indication that you are anaemic. A diet rich in iron and vitamin C is usually all that is required. Occasionally iron tablets are necessary.

Rubella (German Measles)

The test is for immunity. Most women are immune either because they have already had rubella or because they have been vaccinated. If you are not immune you must take care to avoid anyone who is suspected of having rubella. If caught in early pregnancy the baby could suffer serious damage to the brain, heart, ears and eyes.

Vaccination can be given soon after birth but it is essential you do not become pregnant again for 1 month afterwards.


Syphilis is a sexually transmitted disease a woman can have without feeling unwell. Untreated it can pass to the baby through the placenta and cause damage to the brain and bones.

Hepatitis B

Hepatitis B is a virus that affects the liver and may cause liver failure or liver cancer. Many people who carry the virus are unaware of it. Infected babies can develop serious liver problems. If you have hepatitis B your baby can be protected by vaccination soon after birth.

Human Imunodeficiency Virus (HIV)

HIV affects the body’s ability to fight infection. HIV can be transmitted from a mother to her child during pregnancy, labour or through breast feeding. Treatment given in pregnancy can reduce this risk. Additional blood tests may be appropriate or offered depending on individual circumstances.