What it means to be Rhesus Negative

When a pregnant woman first goes to her doctor or clinic, a blood sample is sent to the laboratory and tested to see if she is…

RHESUS POSITIVE
or
RHESUS NEGATIVE

What is Rhesus?

Rhesus is the name given to a structure, made of protein, on the surface of red blood cells.

This structure is present on everyone’s red cells, but it is not identical in everyone. In the same way that some people have blue eyes and some have brown eyes, there are two main types of rhesus structure.

The more common type is called Rhesus Positive.

The other type is called Rhesus Negative.

What does being Rhesus Negative mean for my baby and me?

Being rhesus negative is not an illness or disease. It simply describes what type of blood you have. Just as brown eyes see as well as blue eyes, rhesus negative blood cells work as well as rhesus positive ones.

Your rhesus type only matters to you when you are pregnant.

If your partner is rhesus positive, your baby can inherit his rhesus positive blood type.

For your first rhesus positive baby, there is usually no problem, and the pregnancy and birth proceed normally. However, during any pregnancy small amounts of the baby’s blood can escape across the placenta into the mother’s bloodstream.

This can happen if you have a vaginal bleed, or a bad fall, or if you are involved in a car accident. It is especially common at the birth of your baby or after a miscarriage.

Your body can react to the rhesus positive blood cells from your baby and create anti-bodies that can damage the blood cells of your rhesus positive baby.

What should be done to protect my baby?

All Rhesus Negative mothers should have a blood test taken from the umbilical cord of the baby following delivery.

If the baby’s blood group is rhesus positive then the mother will be given an Anti-D injection as soon as is possible after the delivery. The Anti-D injection should be given within 72 hours of the delivery of the baby. You will also need an injection of Anti-D at other times during the course of your pregnancy such as following a vaginal bleed or an accident involving trauma to the abdomen.

Giving this injection within a period of 72 hours the Anti-D will destroy any of the baby’s red cells that have leaked into the mother’s bloodstream. Because the baby’s red blood cells are destroyed so quickly by Anti-D the mother’s defence system is not given a chance to make anti-bodies which would be stored for a future pregnancy. In this way problems in future pregnancies are avoided. The Anti-D that has been injected into the mother is cleared by her body by three months.

What is Anti-D?

Anti-D is an immunoglobulin/protein that is produced from human plasma. Plasma is the fluid part of blood which is separated from blood donations. The anti-D immunoglobulin /protein is taken from the plasma and prepared so it can be given by injection.

Is the Anti-D harmful to my baby?

Anti-D given to a mother during pregnancy does not harm the baby in any way.

Is the injected Anti-D Safe?

Yes. Anti-D in use today is very safe. It does not cause unwanted effects in the mother or baby, or in future pregnancies.

Stringent controls and tests are in place at all stages of manufacture to ensure that Anti-D does not transmit infection.

What should I do?

Remember: If you have an

Accident

If you are involved in a minor car accident during your pregnancy or have a bad fall

OR

Bleeding

If you have vaginal bleeding during your pregnancy

THEN

Contact your doctor or midwife straight away.

Prompt treatment with Ant-D will prevent you developing antibodies. This may be important for the health of your baby during this pregnancy and in future pregnancies.

You may find it helpful to discuss this subject with your doctor or midwife at your next visit to the clinic or surgery.