Rhesus DIsease

Question 1

What d moes it mean to be Rhesus negative?

Answer 1

RhD ^- means that the red blood cells do not carry RhD antigen

If RhD- woman is carrying RhD+ foetus and any foetal blood cross into maternal circulation (sensitizing event) → maternal reaction to the ‘foreign D’ antigens on RBCs of the foetus → antibodies anti D are produced → problem not in a current pregnancy but in a later ones (antibodies from mum may cross the placenta and destroy foetal RBCs)

This leads to haemolytic disease of newborn and either severe disability or stillbirth

Question 2

When to do routine anti-D prophylaxis for women that are RhD-?

Answer 2

at 28 weeks, 34 weeks and if after a baby is born and its blood is tested as RhD + then we also give postnatal anti-D prophylaxis

Question 3

How does anti-D prophylaxis work?

Answer 3

• Anti-D prophylaxis prevents RhD- women from producing anti-D antibodies against RhD+ foetus
• This is achieved because anti-D immunoglobulins are already provided (so immune system of the mum does not need to produce a new ones)

Question 4

What’s a sensitizing event?

Answer 4

An event when a foetal blood could pass into maternal circulation

Question 5

What are the doses of anti-D prophylaxis:

• before 20 weeks gestation
• after 20 weeks gestation

Answer 5

• before 20 weeks: 250 iu
• after 20 weeks: 500 iu

Question 6

Timing and route of anti-D prophylaxis after a sensitizing event has occurred

Answer 6

• give ASAP after a sensitising event (ideally within 72 hours)* still some protection if given within 10 days
• IM injection

Question 7

Do we give prophylactic anti-D to RhD- women following abortion?

Answer 7

Yes. This is regardless of abortion being medical or surgical → we give anti-D for both

Question 8

Do we give anti-D prophylaxis to non-sensitised RhD- women in case of ectopic pregnancy?

Answer 8

Yes

Question 9

Do we give anti-D prophylaxis to non-sensitised RhD- women in case of spontaneous miscarriage?

Answer 9

Yes. To all types of miscarriage after 12 weeks pregnancy

(given even for threatened miscarriage)

* if miscarriage occurred before 12 weeks of gestation → then anti D not required; unless uterine evacuation was performed

Question 10

In what cases, we should give anti-D prophylaxis to RhD- women?

Answer 10

• ectopic pregnancy
• miscarriage (after 12 weeks)
• termination of pregnancy
• antepartum haemorrhage
• closed abdominal injury
• external cephalic version of foetus
• invasive prenatal diagnosis (amniocentesis, foetal blood sampling)
• other intrauterine procedures (
• intrauterine death

Question 11

How much of anti D prophylaxis do we give to RhD- woman after she gave birth to RhD + child?

Answer 11

500 iu of anti - D within 72 hours

(postnatal)

Question 12

If mum is RhD- and dad is RhD- do we need to give anti-D prophylaxis?

Answer 12

No