Preventing rhesus disease

Rhesus disease can largely beprevented by having an injection of a medication called anti-D immunoglobulin.

This can help to avoid a process known as sensitisation, which is when a woman with RhD negative blood is exposed to RhD positive blood and develops an immune response to it.

Blood is known as RhD positive when it has a molecule called the RhD antigen on the surface of the red blood cells.

If the antigens have been neutralised, the mothers blood won't produce antibodies.

You'll be offered anti-D immunoglobulin if it's thought there's a riskthat RhD antigens from your baby have entered your blood for example,if you experience any bleeding, if you have an invasive procedure (such as Amniocentesis ) or if you experience any abdominal injury.

Anti-D immunoglobulin is also administered routinely during the third trimester of your pregnancy if your blood type is RhD negative. This is because it's likely that small amounts of blood from your baby will pass into your blood during this time.

This routine administration of anti-D immunoglobulin is called routine antenatal anti-D prophylaxis, or RAADP (prophylaxis means a step taken to prevent something from happening).

Routine antenatal anti-D prophylaxis (RAADP)

There are currently two ways you can receive RAADP:

• a one-dose treatment: where you receive an injection of immunoglobulinat some point during weeks 28 to 30 of your pregnancy
• a two-dose treatment: where you receive two injections; one during the 28th week and the other during the 34th week of your pregnancy

There doesn't seem to be any difference in the effectiveness between the one-dose or two-dose treatments. Your local clinical commissioning group (CCG) may prefer to use a one-dose treatment, because it can be more efficient in terms of resources and time.

When will RAADP be given?

RAADP is recommended for all pregnant RhD negative women who haven't been sensitised to the RhD antigen, even if you previously had an injection of anti-D immunoglobulin.

AsRAADPdoesn't offer lifelong protection against rhesus disease,it will be offered every time you become pregnant if you meet these criteria.

RAADP won't work if youve already been sensitised. In these cases, you'll be closely monitoredso treatment can begin as soon as possible if problems develop.

Anti-D immunoglobulin after birth

After giving birth, a sample of your baby's blood will be taken from the umbilical cord. If you're RhD negative and your baby is RhD positive, and you haven't already been sensitised, you'll be offered an injection of anti-D immunoglobulin within 72 hours of giving birth.

The injection will destroy any RhD positive blood cells that may have crossed over into your bloodstream during the delivery. This means your blood won't have a chance to produce antibodies and willsignificantly decrease the risk of your next baby having rhesus disease.

Complications from anti-D immunoglobulin

Some women are known to develop a slight short-term allergic reaction to anti-D immunoglobulin, whichcan include a rash or flu -like symptoms.

Although the anti-D immunoglobulin, which is made from donor plasma, will be carefully screened, there's a very small risk that an infection could be transferred through the injection.

However, the evidence in support ofRAADPshows that the benefits of preventing sensitisation far outweigh these small risks.