Hemolytic Disease of the Fetus and Newborn (Part 1) Flashcards
3 classes of HDFN
- ABO HDFN
- Rh HDFN
- “Other” HDFN
Most common class of HDFN
ABO HDFN
Most severe class of HDFN
Rh HDFN
Mechanism of maternal immunization and placental transfer of antibody(ies) in HDFN
When baby is born, the placenta breaks and there is disruption of placental circulation and an exchange of maternal and baby blood. The mother makes antibodies to the foreign cells.
Most common ABO group of a mother who delivers a newborn affected with ABO HDFN
Group O
3 reasons that a first born child is more likely to be affected with ABO HDFN than Rh HDFN
- ABH antigens found widely distributed throughout body
- ABH antigens are not fully developed in fetal life
- IgG titer of ABO Abs is usually much lower than anti-D because most ABO antibodies are IgM; less cross placental and less damage to cells
3 reasons for the severity of Rh HDFN
- Rh is only found on red blood cells
- Rh antigens are fully developed at birth
- IgG titer is higher because it crosses the placenta
Other HDFN
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How can fetal maternal ABO incompatibility prevent immunization of the mother against Rh or other blood group antigen
In ABO-incompatible pregnancies, the baby’s RBCs are IMMEDIATELY sensitized by the mother’s ABO abs and are quickly removed from her circulation by her liver
HDFN
- mechanism of RBC destruction by maternal antibody
Abs are produced as a result of transfusion or pregnancy. The exposure is usually at the time of delivery.
HDFN
- Response of fetus to RBC destruction
Anemia
HDFN
- Management of bilirubin in utero
Baby’s cells become coated in utero, cells removed by baby’s RES, Hgb breaks down, indirect bili produced, bili removed by moms liver before birth
HDFN
- management of bilirubin after delivery
After birth, baby’s immature liver can not conj bili, so it accumulates in the baby’s system -> kernicterus
HDFN
- greatest danger to the fetus in utero
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HDFN
- greatest danger to the newborn after delivery
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