Rh Isoimmunization Lecture Notes

Flashcards summarizing Rh isoimmunization and Rh incompatibility

What is Rh isoimmunization?

A condition where an Rh negative mother is exposed to an Rh positive fetus.

What happens when an Rh negative mother is exposed to an Rh positive fetus?

The mother develops antibodies against Rh positive fetal blood cells.

What can result from Rh incompatibility?

Hemolytic disease (fetal anemia) in the baby due to the mother's antibodies attacking the baby’s RBCs.

Why does Rh incompatibility not affect the mother?

The mother's immune system considers the Rh+ baby as a foreign body, but the reaction primarily impacts the fetus.

Why does Rh incompatibility rarely cause complications in the first pregnancy?

During the first pregnancy, fetal blood may not mix with the mother's blood until delivery, so the mother's body may not produce antibodies against the Rh factor until after birth.

When is mixing of maternal and fetal blood most likely to occur?

During vaginal deliveries, and less likely with C-section unless there is damage to the placenta during the surgical delivery.

List some complications of Rh incompatibility.

Hemolytic Anemia, Jaundice (Kernicterus), Enlarged spleen, Hydrops Fetalis, Stillbirth

What is Kernicterus and what causes it?

Brain damage caused by high levels of bilirubin in the fetal blood.

How is Rh isoimmunization treated?

With Rh immunoglobulin (Rho-Gam) given at 28 weeks of pregnancy and within 72 hours after delivery, intrauterine blood transfusion, and close maternal-fetal monitoring.

When is Rho-Gam typically administered?

At 28 weeks of pregnancy and within 72 hours after delivery.

What is the Indirect Coombs test?

A test used to determine if the mother has developed antibodies against Rh-positive blood.

Explain the pathophysiology of Rh isoimmunization.

The mother's body produces antibodies that recognize the Rh antigen on fetal red blood cells as foreign, leading to an immune response.

What is Hydrops Fetalis?

A severe form of fetal anemia where the fetus has widespread edema and fluid accumulation in body cavities.

How does Rho-Gam work to prevent Rh isoimmunization?

By administering Rh immunoglobulin (Rho-Gam) to the mother, it prevents her immune system from recognizing and producing antibodies against the Rh-positive fetal cells.

What is intrauterine blood transfusion?

A procedure where fetal red blood cells are replaced with Rh-negative red blood cells to treat severe anemia before delivery.

What other types of maternal-fetal blood incompatibilities can occur?

ABO incompatibility is another type, where the mother has type O blood and the fetus has type A, B, or AB. It is generally less severe than Rh incompatibility.

Can ABO incompatibility lead to hydrops fetalis?

Rarely. ABO incompatibility is usually milder, and hydrops fetalis is uncommon.

How is ABO incompatibility treated?

Treatment includes phototherapy to reduce bilirubin levels and, in severe cases, exchange transfusions.

What are the risk factors for Rh isoimmunization?

Previous Rh-incompatible pregnancies, miscarriages, ectopic pregnancies, abortions, amniocentesis, and external cephalic version can increase the risk.

Explain electronic fetal monitoring in Rh-sensitized pregnancies.

Electronic fetal monitoring is used to assess fetal well-being, detecting signs of fetal anemia or distress, which may indicate the need for intervention.