immune reactions of placenta Flashcards
what is erythroblastosis fetalis?
an immune reaction in placenta
when does erhythroblastosis fetalis occur?
when the mother is Rh- and the fetus is Rh+. If fetal RBCs mix with maternal blood, the mother forms antibodies which can traverse the placenta and lead to hemolysis and anemia. severe cases also have greatly increased bilirubin which may cause fetal cerebral damage.
when does fetal blood mix with maternal blood?
usually at birth, so first Rh+ child is unaffected.
why can a second Rh+ fetus be at risk?
because mother created antibodies to Rh.
how does an Rh+ fetus with erythroblastosis fetalis compensate for hemolysis?
increases production of erythroblasts which differentiate into RBCs.
what viruses can cross the placenta?
rubella- german measles
cytomegalovirus - mononucleosis
can bacteria cross placenta?
yes, syphilis, for example.
