Rh incompatibility

introduction of rh alloimmunization

1. Rh INCOMPATIBILITY

2. Proteins (antigens) occurring only on surface of RBC’s Rh + if proteins present Rh – if proteins absent A+, A-, B+, B-, AB+, AB-, O+, O- Most important for pregnancy Inheritance is Autosomal Dominant 15% Caucasian population are Rh- Rh FACTOR

3. INTRODUCTION During Pregnancy, the mother and the fetus have different Rh protein factors, this condition is called Rh incompatibility . Like our blood type, we inherit our Rh factor type from our parents . Most people are Rh-positive, but a small percentage of people are Rh-negative Rh factor doesn’t directly affect the health . However , Rh factor becomes important during pregnancy .

4. Rhesus disease is a condition where antibodies in a pregnant woman's blood destroy her baby's blood cells. It's also known as  haemolytic disease of the fetus and newborn (HDFN). If the mother is Rh-negative and her baby is Rh-positive, during pregnancy (and especially during labor and delivery) some of the fetus's Rh-positive red blood cells may get into the mother's bloodstream. SENSITIZATION – The process in which mother’s body will try to fight them off by producing antibodies against them. Rh DISEASE?

5. Potential sensitizing events for Rhesus Disease Miscarriage Termination of pregnancy Antepartum haemorrhage Invasive prenatal testing (amniocentesis, cordocentesis etc.) Delivery Ectopic pregnancy

6. PATHOPHYSIOLOGY

7. CAUSES Ectopic pregnancy Partial molar pregnancy Blighted ovum Antepartum bleeding External version Platelet transfusion Placenta previa Placental abruption Abdominal/pelvic trauma In utero fetal death Any invasive obstetric procedure ( eg , amniocentesis) Lack of prenatal care Postpartum ( Rh+baby ) Spontaneous abortion

8. Rh incompatibility can cause symptoms ranging from very mild to deadly. In its mildest form, Rh incompatibility causes the destruction of red blood cells. There are no other effects. After birth, the infant may have: Yellowing of the skin and whites of the eyes (jaundice) Low muscle tone  ( hypotonia ) L ethargy Swelling or edema ( hydrops fetalis ) SYMPTOMS

9. Signs of fetal anemia Polyhydramnios Enlarged fetal heart Ascites and pericardial effusions Hyperdynamic fetal circulation (MCA doppler ) Reduced fetal movements Abnormal CTG with reduced variability

10. Diagnosis MCA doppler Cell free DNA Kleihauer test Amniocentesis and liley graph Direct coomb’s test

11. SCREENING TESTS ABO & Rh Ab at 1 st prenatal visit At 28 weeks Postpartum Bleeding Antepartum bleeding and before giving any immune globulin Neonatal bloods ABO, Rh GOLD STANDARD TESTS Indirect Coombs: mix Rh(D)+ cells with maternal serum anti-Rh(D ) Ab will adhere RBC’s then washed & suspended in Coombs serum RBC’s coated with Ab will be agglutinated Direct Coombs: mix infant’s RBC’s with Coombs serum maternal Ab present if cells agglutinate

12. Non Reliable Parameters: Placental thickness Umbilical vein diameter Hepatic size Splenic size Polyhydramnios Visualization of walls of fetal bowel from small amounts intra abdominal fluid may be 1 st sign of impending hydrops U/S reliable for hydrops (ascites, pleural effusions, skin edema) – Hgb < 70 Ultrasound Parameters

13. COMPLICATIONS DURING PREGNANCY Mild anemia, hyperbilirubinemia and jaundice . Severe anemia with enlargement of the liver and spleen.  Hydrops fetalis .  AFTER BIRTH Severe hyperbilirubinemia and jaundice.  Kernicterus

14. Management Anti D immunoglobulin Fetal blood transfusion (fetal Hct <30%) Phototherapy

15. Routes of administration- Into umbilical vein at the point of cord insertion Into intrahepatic vein Into peritoneal cavity Into fetal heart Transfused blood- RhD negative Crossmatched with a maternal sample Densely packed ( Hb around 30g/L) White cell depleted and irradiated Screened for infection including CMV

16. Prophylactic vaccinations- During every pregnancy After a miscarriage or abortion After prenatal tests such as amniocentesis and chorionic villus biopsy After injury to the abdomen during pregnancy