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Blood test in pregnancy means fewer anti-D injections required

Published: 13 May 2024

Around 2,000 fewer women in Wales will need to have an anti-D injection during their pregnancy, thanks to a new cell-free fetal DNA testing programme being launched today. 

Until now, all pregnant women with a RhD negative blood group (previously called Rhesus negative) have been offered the anti-D injection to prevent Haemolytic Disease of the Fetus and Newborn (HDFN) – also known as Rhesus disease. 

The introduction of a simple blood test to the screening pathway will be offered to all RhD negative women who do not have maternal antibodies. This can be offered at around the 16th week of pregnancy, and can accurately predict the blood type of the baby. This means that the anti-D injection can be accurately targeted at those women who need it. 

HDFN is a condition that can occur when a mother has RhD negative blood and the baby in her womb has RhD positive blood.  It can cause serious consequences but is rare because women with RhD negative blood are offered injections of a medication called anti-D immunoglobulin.  

Sarah Fox, Head of Programme for Antenatal Screening Wales, said: “This new test means that we are able to predict a baby’s blood group in the womb, and therefore only those women whose babies are predicted to be RhD positive will need to have this injection. 

“The introduction of this test follows a recommendation by the National Institute for Clinical Excellence (NICE). It means women can now make an informed choice and we can reduce unnecessary use of this treatment in pregnant women, as well as ensuring that supplies of anti-D immunoglobulin are conserved for those who need it most.” 

More information on HDFN can be found on the NHS 111 Wales website.