08/10/2013
When you're pregnant, blood from your baby can cross into your bloodstream, especially during delivery. If you're Rh-negative and your baby is Rh-positive, your body will react to the baby's blood as a foreign substance.
Your body will create antibodies (proteins) against the baby's Rh-positive blood. These antibodies usually don't cause problems during a first pregnancy. This is because the baby often is born before many of the antibodies develop.
However, the antibodies stay in your body once they have formed. Thus, Rh incompatibility is more likely to cause problems in second or later pregnancies (if the baby is Rh-positive).
The Rh antibodies can cross the placenta and attack the baby's red blood cells. This can lead to hemolytic anemia (HEE-moh-lit-ick uh-NEE-me-uh) in the baby.
Hemolytic anemia is a condition in which red blood cells are destroyed faster than the body can replace them. Red blood cells carry oxygen to all parts of the body.
Without enough red blood cells, your baby won't get enough oxygen. This can lead to serious problems. Severe hemolytic anemia may even be fatal to the child.