What should you know about pathophysiology of rh incompatibility?

Rh status refers to a marker on red blood cells. If an Rh-negative person encounters Rh-positive blood, the immune system may recognise the marker as unfamiliar and produce anti-D antibodies. Blood mixing can happen during pregnancy, birth, bleeding, pregnancy loss, abdominal injury or procedures. The first exposure may sensitise the immune system rather than cause immediate illness.

In a later pregnancy with an Rh-positive fetus, antibodies can cross the placenta and attach to fetal red blood cells. Their breakdown may cause fetal or newborn anaemia and jaundice. Screening identifies the pregnant person’s blood group and antibody status so the maternity team can choose monitoring and prevention.

Attend routine blood-group and antibody screening, and tell the maternity team promptly about bleeding, abdominal trauma, pregnancy loss or an invasive procedure. Anti-D Injection may be offered when appropriate to prevent sensitisation; it does not remove antibodies that have already formed. If antibodies are present, care may include repeat blood tests and fetal monitoring. Keep records of previous pregnancies, transfusions and anti-D treatment.

Contact your maternity service promptly after vaginal bleeding, abdominal injury, pregnancy loss, or a procedure during pregnancy, even if you feel well. Seek urgent care for heavy bleeding, severe abdominal pain, fainting, or reduced fetal movement. The team can determine whether testing, monitoring or preventive treatment is needed.

What is my Rh status and antibody result? Could this event expose my blood to fetal blood? Is Anti-D Injection recommended, and when? If antibodies are present, how will the pregnancy be monitored? What should I do after bleeding or an injury?