Rhesus-D problems

Question 1

When does the rhesus status of the mother potentially have implications foe a baby?

Answer 1

When the mother is rhesus negative and child is rhesus positive

Question 2

Why is a rhesus negative mother with a rhesus positive child a bad thing?

Answer 2

Leakage fo foetal RBC into Rh -ve mother circulation may stimulate her to produce anti-D IgG antibodies. This means that in subsequent pregnancies these can cross the placenta, causign rhesus haemolytic disease

Question 3

What specific things can occur in first pregnancies which can increase the risk of developing isoimmunisation?

Answer 3

• Threatened miscarriage
• APH
• Mild trauma
• Amniocentesis
• Chorionic villous sampling
• External cephalic version

Question 4

What is severe rhesus haemolytic disease also known as?

Answer 4

Hydrops foetalis

Question 5

When should anti-D be given in miscarriage?

Answer 5

• All Rh-ve mothers with medical or surgical termination of pregnancy, hydatiform mole, and ectopic pregnancy
• Spontaneous miscarriage followed by medical/surgical evacuation
• Spiontaenous complete miscarriage after 12 weeks
• Threatened miscarriage after 12 weeks

Question 6

What are signs of rhesus haemolytic disease of the newborn?

Answer 6

• Jaundice - day 1
• CCF
• Hepatosplenomegaly
• Bleeding
• Kernicterus

Question 7

If a pregnant woman was rhesus negative, when should she get Anti-D injection?

Answer 7

28 and 34 weeks - 500units

Question 8

How does giving Anti-D antibodies prevent rhesus disease?

Answer 8

Can prevent temporary sensitization of the maternal immune system to Rh D antigens by “mopping them up”

Question 9

What dose of anti-D should you use before 20 weeks gesation (e.g. if the mother has had a miscarriage)?

Answer 9

250units

Question 10

What dose of Anti-D would you give a Rh-ve mother after 20 weeks gestation?

Answer 10

500 units

Question 11

If the baby’srhesus status is unknown, and their mother is rhesus negative, should the mother be given anti-D?

Answer 11

Yes - assume baby is rhesus positive

Question 12

What is a kleihauer test?

Answer 12

Blood test used to measure the amount of fetal hemoglobin transferred from a fetus to a mother’s bloodstream.

Question 13

What is a kleihauer test used for?

Answer 13

Standard method for quantifying foetal-maternal haemorrhage

Usually performed on Rh-negative mothers to determine the required dose of Rho(D) immune globulin (RhIg) to inhibit formation of Rh antibodies in the mother and prevent Rh disease in future Rh-positive children