Rh Immunization Flashcards
Investigations for Rh negative pregnancy
Indirect coombs test
In non immunized primi done at 28weeks
In multi done at first visit and repeat at 28 weeks - if negative give anti-D prophylaxis
In immunized mother, repeat every 4w , critical>1/160
Findings in obstetrics Doppler
Umbilical artery
MCA Doppler velocity can detect foetal anemia at an early stage
What does Rh immunization depend on?
Degree of fetomaternal haemorrhage
Immune response of mother
ABO incompatibility
Conditions which require Anti D Prophylaxisis
•Threatened, missed and spontaneous abortion
•ECV,IUD,APH
•delivery by vaginal or LSCS and removal of placenta
Usg findings in hydrops fetalis
Large placenta, polyhydramnios
Hepatosplenomegaly
Fluid collection in cavities
How is foetal anemia assessed?
Using Doppler - MCA- peak systolic velocity value above 15MOM ( multiples of median) indicates anaemia
What is liley’s curve?
It is an indirect measure for fetal haemolysis - measures the bilirubin in amniocentesis and plotted in graph - based on the amount of deviation in 450nm
What are the degrees of haemolytic disease of newborn?
Mild- anaemia develops due to haemolysis of fetal RBCs : Congenital anaemia
New born alive but jaundice develops in 24hrs: Icterus gravis Neonatorum
Severe haemolytic disease - IUD: hydrops foetalis
Precautions taken to conduct normal labour to prevent Rh isoimmunization
No intrauterine manipulation
Early cord clamping
LSCS - removal of blood from peritoneal cavity, mopping of blood
What is Kleihauer betke test?
It is a test to detect fetomaternal haemorrhage. Based on acid elusion test- fetal RBCs more resistant than maternal RBCs
If 80 foetal RBCs present then 4ml of fetomaternal haemorrhage is present
Every 1ml -10ug of Rh immunoglobulin is given
What is Coomb’s test?
DCT- done in cord blood to identify Rh antibodies in foetal RBCs
ICY- free antigens inaternal serum are tested after incubation with RBCs of specific antigen - test for maternal ab
Critical titre 1:160
Postnatal prophylaxis
300ug of Rh anti D immunoglobulin, within 72 hrs of delivery and if missed it can be given upto 28d postpartum
50ug post abortion or mtp
Management of newborn
Phototherapy
Phenobarbitone - enhances conjugation of bilirubin
Exchange transfusion- cord length is kept long for cannulation
When to deliver
If MCA < 1.5MoM delivery at 37-38w
If MCA > 1.5MoM delivery , when <34w - foetal blood sampling via cordocentesis , if low intrauterine transfusion
>34w then give cortisone and deliver
When to deliver
If MCA < 1.5MoM delivery at 37-38w
If MCA > 1.5MoM delivery , when <34w - foetal blood sampling via cordocentesis , if low intrauterine transfusion
>34w then give cortisone and deliver
