what are the sequences of event hat result in erythroblastosis fetalis
Erythroblastosis fetalis, also known as Hemolytic Disease of the Newborn (HDN), occurs when there is an incompatibility between the blood types of a mother and her unborn baby. The main sequence of events leading to erythroblastosis fetalis is as follows:
1. Blood type incompatibility: The mother's blood type is usually type O, A, or B, while the baby's blood type is typically determined by the father's blood type. If the mother is Rh-negative (lacks the Rh factor protein) and the father is Rh-positive (has the Rh factor protein), there is a potential for incompatibility as the baby could inherit the Rh factor from the father.
2. Maternal sensitization: During pregnancy, a small amount of fetal blood can mix with the mother's bloodstream, usually during delivery or other pregnancy-related complications. If the baby is Rh-positive and some of its Rh-positive red blood cells enter the Rh-negative mother's bloodstream, the mother's immune system might produce antibodies against the Rh factor, causing sensitization.
3. Sensitization during a previous pregnancy or blood transfusion: If a mother has been previously sensitized to the Rh factor during a previous pregnancy or blood transfusion, her immune system might already have developed antibodies against the Rh factor.
4. Subsequent pregnancies: In subsequent pregnancies with an Rh-positive baby, the mother's immune system, now sensitized to the Rh factor, can produce antibodies that cross the placenta barrier and attack the red blood cells of the unborn baby.
5. Hemolysis of the fetal red blood cells: The antibodies produced by the mother can attach to the baby's red blood cells, leading to their destruction (hemolysis) and subsequent release of bilirubin. Elevated levels of bilirubin can result in various complications, such as anemia, jaundice, and in severe cases, organ damage.
6. Treatment: If erythroblastosis fetalis is detected during pregnancy, the mother may receive injections of Rh immune globulin (RhoGAM) around 28 weeks gestation and within 72 hours after delivery. RhoGAM prevents sensitization by blocking the mother's immune system from producing antibodies against the Rh factor.
It's important to note that due to advances in prenatal screening and medical interventions, the occurrence of erythroblastosis fetalis has significantly decreased.