Module 11 (Final) Flashcards
Rh Incompatibility
Rh - mother carrying a Rh + fetus
Mother’s body considers Rh+ blood an antigen and an antibody response is triggered.
When does Rh incompatibility take place?
Pregnancy: small amount of fetal blood may enter maternal circulation VIA microtears in placenta
Placental separation (greatest risk): Larger amounts of fetal blood enter maternal circulation
Fetal/Newborn Effect of Rh incompatibility
Antibodies from mother attack Rh+ blood cells. Hemolysis of fetal/newborn RBCs takes place.
Result: hemolytic anemia, pathological jaundice
How is Rh incompatibility prevented?
Rhogam
What does Rhogam do?
Suppresses mother’s normal immune response. The mother’s cells no longer recognize fetal cells as foreign and no antibody formation occurs.
How long does Rhogam last?
12 weeks
Coombs Test
Identifies antibodies to Rh+ blood. It is interpreted as positive or negative.
Direct Coombs
Done on baby. Identifies antibodies to Rh+ blood in the neonate’s serum.
Indirect Coombs
Done on momma. Identifies antibodies to Rh+ blood in maternal serum.
Negative: no antibodies. given rhogam.
Positive: antibodies. No rhogam (too late). The fetus is at risk for hemolytic anemia and pathological jaundice.
When is indirect coombs testing performed?
Indirect coombs testing is performed on all Rh- women at about 28 weeks’ gestation
When is direct coombs testing performed?
postpartum, on a neonate with a Rh + blood sample.
Negative: mother recieves Rhogam within 72 hours to prevent antibody formation to protect future pregnancies.
Positive: Infant has been exposed to maternal antibodies. Monitor infant for jaundice. Treat infant for hemolytic anemia (transfusion)
When does ABO incompatibility occur?
Type O mother, Type A, B or AB fetus
Mother may have naturally occurring antibodies to blood type A or B, so sensitation does not necessarily have to be from fetal/maternal blood crossing.
Antibodies hemolyze type A and/or type B RBCs. Typically mild.
Effects of ABO incompatibility on the newborn and fetus
Fetus: No effects
Newborn: Potential hemolytic anemia, potential jaundice
How would you manage ABO incompatibility postpartum?
If mother is blood type O: Determine newborn blood type and perform direct coombs to detect antibodies to both blood type and Rh.
Coombs Positive: Monitor infant for jaundice, anticipate treatment for possible pathologic jaundice and/or hemolytic anemia (HA is rare)
Negative: Infant not at risk. No interventions necessary.
PP Hemorrhage Vaginal Birth
greater that 500mL blood loss
PP Hemorrhage Cesarean Birth
greater that 1000mL blood loss
Other criterion for PP Hemorrhage
Decrease in HCT of 10% or more from admission