Understanding what is a negative blood group and why your Midwife or Doctor is suggesting Anti-D is given at regular times during pregnancy.
***Key Points***
It is important to know your blood group and type during pregnancy.
When the mother is one blood type (negative) and the baby is another (positive) – if some of the baby’s blood mixes with the mother’s blood during pregnancy or birth, the mother’s blood can produce antibodies against the Rhesus positive blood cells that belong to the baby.
These are called anti-D antibodies, this doesn’t usually affect the first pregnancy but in other pregnancies the mother’s bodies will produce more antibodies that will destroy the baby’s blood cells, the baby can become very unwell.
To prevent this from happening, an injection of anti-D immunoglobulin (known as anti-D) is offered to women with negative blood group.
***Key Points***
***Rh Negative explained***
You may have one of four blood groups – A, B, AB, or O, and either be negative or positive. You get your blood type from your parents. If you have a negative blood group it is known as RhD (Rhesus factor) negative.
The Rhesus shows that on the surface of your blood cells you have a protein known as ‘D antigen’. Negative blood types are not as common as those who are positive and only during pregnancy is it relevant to the health outcomes of your baby.
***Rh Negative explained***
***Rh Negative in pregnancy***
When you have early blood tests in pregnancy your blood group will be tested, if you have a negative blood group you will be offered anti-D at around 28 weeks and 34 weeks of pregnancy when it is known that your partner has a positive blood group.
You will have anti-body screening offered during pregnancy and before the scheduled anti-D administration times. Tests will be done after pregnancy and anti-D may be offered after birth too.
Anti-D is an injection that is administered to the mother if she has negative blood group and been exposed to positive blood [from the baby], it prevents a process called sensitisation. The anti-D neutralises any RhD positive antigens that may be in the bloodstream.
Things that may be a sensitising event may include – bleeding, invasive procedure (such as amniocentesis) or trauma to the pregnant abdomen.
***Rh Negative in pregnancy***
REFERENCES
RANZCOG Anti-D in pregnancy and after the birth
