The screening can also be carried out even if you have a multiple pregnancy (twins or more). It is important that you are aware that this is the ONLY information about your baby’s DNA that is screened for during this test. At this point of pregnancy, some of your baby’s DNA (genetic information) will be detectable in your blood stream making it possible to predict whether your unborn baby is RhD negative or RhD positive. This involves taking a blood sample from you from 11+2 weeks onwards. The Rosie hospital, together with NHS Blood and Transplant (NHSBT), can now offer a simple screening test to predict your baby’s blood type – called fetal RhD screening. By identifying an unborn baby’s blood group, we can reduce the amount of unnecessary anti-D injections that are given. In about one in three pregnancies, the baby will be RhD negative and an anti-D injection would therefore not be necessary. Sensitisation is permanent and cannot be undone.Īnti-D is only needed if an RhD negative woman or person is pregnant with an RhD positive baby. It is important to know that without anti-D sensitisation cannot be prevented and once sensitised, anti-D treatment is no longer effective. Anti-D is also recommended as a treatment if you experience a potentially sensitising event. This reduces the chance of sensitisation to 0.35%. Today HDFN is an uncommon condition as it can be easily prevented through the administration of prophylactic anti-D injection given at 28 weeks and after birth. The antibodies remain in your blood so this is why HDFN can occur in future pregnancies once sensitised. However, HDFN can be very serious and lead to severe anaemia and jaundice which can cause babies to be stillborn, die after birth or have severe, permanent disabilities. This is treatable but requires a longer postnatal stay for your baby and in some cases a blood transfusion. HDFN is sometimes very mild but can still cause jaundice. This can cause babies to have a condition called haemolytic disease of the fetus and newborn (HDFN) – also known as “Rhesus disease”. This can affect future pregnancies because the antibodies now present in your blood can cross the placenta and attack the blood cells of an RhD positive baby. Once sensitisation has occurred it is irreversible. An event that could cause an FMH where you produce antibodies against the D antigen is called a ‘potentially sensitising event’. It can also occur following an episode of vaginal bleeding or an injury to your bump. However, it can happen at other times in pregnancy, for example during a miscarriage or abortion, or following a medical procedure such as amniocentesis. The most common time when your baby’s blood cells may enter your bloodstream is at the time of birth. This is known as sensitisation or “alloimmunisation” and it depends on how big the volume of FMH is and the level of your immune response to this. Should a large enough amount of blood cells from an RhD positive baby enter your blood, you will react to the D antigen in your baby’s blood as though it is a foreign substance and antibodies will be produced against it. Your rhesus status is not a problem if you are RhD positive and your baby is RhD negative.ĭuring pregnancy it is possible that your baby’s blood cells could enter your bloodstream in an event known as a feto-maternal haemorrhage (FMH). However, not all babies born to an RhD positive biological father or sperm donor will be RhD positive, because the biological father or sperm donor may have both RhD positive and RhD negative genes. This can only happen if the baby’s biological father or sperm donor is RhD positive. Your rhesus status matters if you are RhD negative and become pregnant with a baby who is RhD positive. There is a useful A-Z of terms at the end of this information sheet. The information in this leaflet is based on current guidance from NICE (National Institute for Health and Care Excellence) and NHS Blood and Transplant (NHSBT). It provides advice on how having this blood type affects your pregnancy, and what tests and treatments are available to you during pregnancy and after the birth of your baby. The following information is for pregnant women and people who have been advised by their healthcare professional that their blood type is RhD negative. Whether a person is RhD positive or RhD negative is determined by their genes, that is, it is inherited from their parents. People who are RhD negative do not have the rhesus D antigen on their red blood cells. In the UK around 85% of people are RhD positive and 15% RhD negative. Together these are usually shortened, for example to “A positive” or “O negative”. They are also either rhesus (RhD) positive or rhesus (RhD) negative. People can belong to one of four blood groups: A, B, AB & O. Just as every human being is unique, so are the characteristics of your blood.
0 Comments
Leave a Reply. |