Researchers at the University of Bristol, UK, have come up with a new test for identifying a mismatch between the blood of a pregnant woman and her baby. Problems may occur if a pregnant woman’s blood is Rhesus, Rh-negative and her baby’s is Rh-positive. Rh-positive blood contains a substance called Rhd antigen, which passes to the mother’s blood at birth. Usually, there are no problems in a woman’s first pregnancy but, if she has another Rh-positive baby, these anti-bodies cross the placenta and destroy the baby’s red blood cells, causing blood disorders, known as haemolytic diseases, that can be fatal.
To prevent this, pregnant women should have their blood tested at their first antenatal. Rh-negative women are given one or two antiserum injections during pegnancy.
Researchers at the Blood and Transplant Centre in the university discovered new ways for predicting a baby’s blood group by typing its DNA in the plasma of Rh-negative pregnant women. Testing would help avoid unnecessary treatment in about 38 per cent of Rh-negative women and thereby avoid discomfort, inconveniences and risk o exposure to donor blood products that such injections entail.