If incompatible blood types mix between a mother and baby during pregnancy, the mother's immune system may produce antibodies that attack the baby's red blood cells. This is known as Rh sensitization or Rh incompatibility.
Understanding Rh Incompatibility
Rh incompatibility occurs when a mother is Rh-negative (Rh-) and her baby is Rh-positive (Rh+). Rh factor is a protein found on the surface of red blood cells. If the mother's blood comes into contact with the baby's Rh+ blood, her immune system recognizes the Rh factor as foreign and produces antibodies against it. The most common time this occurs is during labor and delivery, but it can also happen during certain medical procedures or trauma during pregnancy.
Consequences of Rh Sensitization
- First Pregnancy: Typically, Rh sensitization doesn't cause problems during the first pregnancy, as it takes time for the mother to develop a significant amount of antibodies.
- Subsequent Pregnancies: However, if the mother becomes pregnant with another Rh+ baby in the future, these antibodies can cross the placenta and attack the baby's red blood cells. This can lead to:
- Hemolytic Disease of the Fetus and Newborn (HDFN): This condition causes the baby's red blood cells to break down faster than the body can replace them. This can lead to anemia, jaundice, brain damage, heart failure, and even death.
- Miscarriage or Stillbirth: In severe cases, the baby may not survive.
Prevention and Treatment
Fortunately, Rh incompatibility is largely preventable with Rh immunoglobulin (RhIg), such as RhoGAM. This medication contains Rh antibodies that prevent the mother's immune system from producing its own antibodies against the baby's Rh+ blood cells.
- RhoGAM Administration: RhIg is typically given to Rh-negative mothers around 28 weeks of pregnancy and again within 72 hours after delivery if the baby is Rh+. It's also given after any event that could potentially cause mixing of fetal and maternal blood, such as amniocentesis, chorionic villus sampling, miscarriage, or abdominal trauma.
- Monitoring: During pregnancy, Rh-negative mothers may be monitored for antibody development through blood tests.
- Treatment for HDFN: If HDFN develops, treatment for the baby may include:
- Blood Transfusions: To replace damaged red blood cells.
- Early Delivery: In severe cases, the baby may be delivered early.
- Intravenous Immunoglobulin (IVIG): To help suppress the immune response.
Summary
While mixing of incompatible blood types between mother and baby can cause serious problems due to Rh sensitization, these risks are significantly reduced with proper prenatal care, including RhIg administration. If you are Rh-negative, talk to your doctor about Rh incompatibility and how to prevent complications.
