Rhesus disease is a condition where antibodies in a pregnant woman's blooddestroy her baby's blood cells. It's also known as haemolytic disease of the foetus and newborn (HDFN).

Rhesus disease doesn'tharm the mother, but it can cause the baby to become anaemic and develop Jaundice in newborns .

Read aboutthe signs of rhesus disease in a baby .

What causes rhesus disease?

Rhesus disease only happens when the mother has rhesus negative blood (RhD negative) and the baby in her womb has rhesus positive blood (RhD positive). The mother must have also been previously sensitised to RhD positive blood.

Sensitisationhappens when a woman with RhD negative blood is exposed to RhD positive blood, usuallyduring a previous pregnancy with an RhD positive baby.The womans body responds to the RhD positive blood by producing antibodies (infection-fighting molecules) that recognise the foreign blood cells and destroy them.

If sensitisation occurs, the next time the woman is exposed to RhD positive blood, her body produces antibodies immediately. If she's pregnant with an RhD positive baby, the antibodies can cross the placenta, causing rhesus disease in the unborn baby. The antibodies can continue attackingthe baby's red blood cells for a few months after birth.

If the mother is RhD negative, she'll be offered injections of anti-D immunoglobulin at certain points in her pregnancy when she may be exposed to the babys red blood cells. This anti-D immunoglobulin helps to remove the RhD foetal blood cells before they can cause sensitisation.

If a woman has developed anti-D antibodies in a previous pregnancy (she's already sensitised) then these immunoglobulin injections don't help. The pregnancy will be monitored more closely than usual, as will the baby after delivery.

A blood transfusion to the unborn baby may be needed in more severe cases. After delivery, the child is likely to be admitted to a neonatal unit (a hospital unit that specialises in caring for newborn babies).

Treatment for rhesus diseaseafter delivery can include a light treatment called phototherapy, blood transfusions, and an injection of asolution of antibodies(intravenous immunoglobulin) to prevent red blood cells being destroyed.

If rhesus disease is left untreated,severe cases can lead to stillbirth . In other cases, it could lead to brain damage,learning difficulties, deafness and blindness . However, treatment is usually effective and these problems are uncommon.

and the potential complications of rhesus disease .

Content supplied by the NHS Website

Medically Reviewed by a doctor on 28 Nov 2016