A fetal screen test is designed to identify if a mother has experienced a placental bleed, potentially allowing fetal blood cells to enter the mother's bloodstream. This is especially crucial when an Rh-negative mother is carrying an Rh-positive fetus.
Purpose of a Fetal Screen Test
The primary purpose of a fetal screen test is:
- Detecting Fetal Blood in Maternal Circulation: This test is done to determine if the mother has experienced a placental bleed which would allow fetal blood cells to enter maternal circulation.
Why is it Important for Rh-Negative Mothers?
The test is particularly vital when an Rh-negative mother is carrying an Rh-positive fetus because:
- Rh Incompatibility: If fetal Rh-positive blood enters the Rh-negative mother's system, it can cause the mother to develop antibodies against the Rh factor.
- Risk to Future Pregnancies: These antibodies can attack Rh-positive fetal blood cells in future pregnancies, leading to hemolytic disease of the newborn (HDN).
- Prevention with RhoGAM: Identifying the presence of fetal blood allows for the administration of RhoGAM, an injection that prevents the mother from developing these harmful antibodies.
