Rhesus Iso-Immunization Flashcards
Rhesus Iso-Immunization
When rhesus positive fetal blood cells pass into rhesus negative maternal circulation=> Sensitization of maternal immune system to fetal blood cells => may give rise to haemolytic diseases in fetus
Causes of Rh Disease
Any Sensitizing events such as
1. Miscarriage
2. Termination of preg.
3. Delivery
4.Invasive procedures
5. Antepartum Haemorrhage
Prevention of Rh Disease
IM injection of Anti-D immunoglobulins within 72 hours of exposure
Anti-D is given routinely for rh -ve mother @
28 and 34 wks
Can Anti-D be given to already sensitized mother
No, useless
How to manage sensitized pregnant woman?
Very close surveillance
Monitor antibody every 2-4 wks
Anti-D test
What is the Anti-D test
Test on maternal blood to meausre how much anti-d is needed for antibodies to become undetectable. (essentially to find out how much antibodies are in maternal circulation)
Results of anti-d test
Less than 4IU/ml= HDFN unlikely
4-15IU/ml= moderate risk
+15Iu/mL= high risk of HDFN and hydrops fetalis
If there are increased antibodies in maternal circulation you should….
examine fetus for signs of anaemia
How to examine fetus for signs of anaemia
Doppler U/S on mid cerebral artery (if MCA velocity is high, high probability of anaemia)
Signs of Fetal Anaemia
Polyhydramnios
Enlarged fetal heart
Ascites
Pericardial effusion
Hyperdynamic fetal circulation
Reduced Fetal movement
Abnormal CTG
Treatment for fetal Anaemia
Delivery if mature enough (not before 36-37wks)
Fetal blood transfusion
Fetal Blood Transfusion is to
restore haemoglobin levels
Adverse effect of Fetal Blood transfusion
Suppresses fetal erythropoiesis
Routes of adminstration of Fetal Blood transfusion
- Umbilical vein
- Intrahepatic Vein
- Peritoneal Cavity (less effective)
4.Fetal heart
