Rhesus Disease

Question 1

Define Rhesus Disease.

Answer 1

Development of Rh Ab in Rh- mother after exposure to Rh+ baby, resulting in haemolytic disease of the fetus and newborn (HDFN).

Question 2

What is the aetiology of Rhesus Disease?

Answer 2

Sensitising event esposes mother to Rh + blood. Maternal Ab develop and subsequent pregnancies with RhD+ fetus, maternal IgG cross placenta and form cmplexes with fetal cells, destroying them. Sensitising events include APH, miscarriage, ectopic pregnancy, TOP, invasive prenatal testing.

Question 3

What are risk factors for Rhesus Disease?

Answer 3

Previous pregnancy with insufficient or none and D prophylaxis

Previous blood transfusion D+

Question 4

Summarise the epidemiology of Rhesus Disease.

Answer 4

1% without prophylaxis.

Question 5

How is Rhesus Disease usually discovered?

Answer 5

Picked up on routine screening, patient may be aware from previous pregnancies. Poor obstetric hx.

Question 6

What investigations should be performed for Rhesus Disease?

Answer 6

Monitoring of maternal Ab levels.

Once threshold reached for anaemia, monitor in a fetal medicine centre with USS, markers of anaemia i.e. MCA doppler. Monitoring maternal including measurement of amniotic BR or cordiocentesis.

Question 7

What is the management of Rhesus Disease?

Answer 7

Prevent: Anti-D Ig prophylaxis required in all RhD- mothers in UK, at 28/40 and 34/40. Follwing sensitizing event, and after delivery if baby RhD+.

Rh immunisaiton in current pregnancy: may necessitate fetal blood transfusion, and exchange transfusion after delivery.

Question 8

What are some complications associated with Rhesus Disease? What is the prognosis for Rhesus Disease?

Answer 8

Hydrops fetalis

IU death

Neonatal death

Kernicterus (hyperBR with brain involvement)