Rhesus incompatibility

Question 1

Rhesus incompatibility explanation

Answer 1

If mother is rhesus negative and baby is rhesus positive

When baby’s blood finds it way into the mother’s bloodstream e.g. during birth, the mother produces antibodies to the rhesus D antigen on the baby’s RBC as it recognises it as foreign - sensitised to Rhesus D antigens

Not a problem in the first pregnancy but if in further pregnancies the baby is rhesus negative then these antibodies attach to the RBCs of the baby and the immune system of the baby will destroy these cells - haemolytic disease of the newborn

Question 2

Management of rhesus incompatibility in pregnancy

Answer 2

Routine anti-D injections at 28 weeks and at birth

Also when there is a sensitising event:

• APH
• Amniocentesis
• Abdominal trauma

Kleihauer test - checks how much foetal blood has passed into the mother’s blood during a sensitisation event. This test is used after any sensitising event past 20 weeks gestation, to assess whether further doses of anti-D is required.