RBC isoimmunisation

Question 1

What Rh status is an issue in a mother?

Answer 1

Rh -ve.

Question 2

What events are potentially Rhesus sensitising?

Answer 2

TOP / ERCP after miscarriage.

Ectopic.

Vaginal bleeding <12weeks or if heavy.

ECV.

Invasive uterine sampling.

Intrauterine death.

Delivery.

Question 3

When is Anti-D given?

Answer 3

Prophylactically: either 1500iu at 28wks or 500iu at 28 and 34wks.

Postnatal: if baby Rh+ve do kleihauer and give 500iu (this covers FMH up to 4ml); above 4ml - 125ug per ml.

Sensitising event: 250iu up to 19+6; 500iu at 20+wks + kleihauer.

Question 4

What are the effects of rhesus disease?

Answer 4

Mild: neonatal jaundice.

Moderate: neonatal anaemia (haemolytic disease of the newborn).

Severe: In utero anaemia -> cardiac failure -> ascites, hydrops -> fetal death.

Question 5

How is anaemia assessed in the fetus?

Answer 5

USS of the MCA - doppler has high sensitivity <36wks.