RH INCOMPATIBILITY Flashcards
What two combinations of fetal and maternal blood type causes Rh incompatibility?
- Mother is Rh negative
- Fetus is Rh positive
How can a fetus have Rh positive blood if the mother is Rh negative
This can only happen if the father of the fetus has an Rh positive blood type.
Rh negative blood is a recessive trait. You can only be Rh negative if BOTH parents are Rh negative.
At which stage of pregnancy does active mixing of maternal and fetal blood usually occur?
This usually happens during the third stage of labour, when active exchange of maternal blood occurs as the placenta separates
What is the main pathophysiologic mechanism of Rh incompatibility?
When blood from an Rh positive fetus enters the blood stream of the mother, maternal circulation develops antibodies.
True or False: Rh incompatibility usually affects the CURRENT pregnancy.
False: The woman’s first Rh positive child is usually unaffected because the maternal antibodies are formed AFTER the birth of the infant. Subsequent Rh-positive fetuses may be affected.
Name the characteristic signs and symptoms of erythroblastosis fetalis, a syndrome caused by the destruction of fetal RBCs.
4H:
Hypoxia
Hyperbilirubinemia
Haemolysis and production of immature RBCs
Hydrops fetalis - generalised edema that occurs as fetus tries to compensate for severe anemia
Which test determines whether the mother has developed any Rh antibodies?
Coomb’s Test
What is given as a preventive measure to a pregnant woman with no antibodies to prevent further formation?
RhoGAM
When is RhoGAM administered?
28 weeks gestation
Which diagnostic test can help measure fetal bilirubin levels if the mother has a positive Coomb’s test?
Evaluate optical density of amniotic fluid via amniocentesis, which is a direct reflection of bilirubin levels (OD high, fetus is in jeopardy)
