Recent updates from the National Blood Authority have refined the approach to RhD testing and Anti-D immunoglobulin in pregnancy. While many recommendations remain unchanged, there are several important updates that GPs should be aware of, particularly during early pregnancy assessment.
Earlier RhD screening
One important change is the recommendation that all women should have an ABO/RhD blood group and antibody screen performed no later than 10 weeks’ gestation. This aligns with current RANZCOG recommendations for routine antenatal assessment and also highlights the need to seek specialist advice for women with weak or variant RhD blood types.
Updated Anti-D recommendations
There is insufficient evidence to suggest that a threatened miscarriage before 12 weeks’ gestation routinely requires anti-D immunoglobulin. However, immunoprophylaxis may be considered where bleeding is repeated or heavy, or is associated with abdominal pain or significant pelvic trauma, in women with no preformed anti-D antibodies. If gestational age is uncertain, ultrasound confirmation and consideration of Anti-D are recommended.
The 2025 RANZCOG Clinical Guideline provides further guidance on the use of anti-D in early pregnancy:
- Threatened miscarriage, miscarriage and medical termination before 10 weeks: Routine Rh D testing and anti-D immunoglobulin are no longer recommended, as there is insufficient evidence that they reduce the risk of sensitisation.
- Surgically managed ectopic pregnancy: Offer anti-D immunoglobulin to women with an Rh D negative blood group.
- Medically or expectantly managed ectopic pregnancy: Evidence for anti-D is insufficient. Consider anti-D following an informed discussion with women who are Rh D negative.
- Anti-D dosing: 250 IU is sufficient for a singleton pregnancy up to 12 weeks’ gestation. 625 IU should be used beyond 12 weeks.
Fetal RhD genotyping
Another significant advance is the introduction of fetal RhD screening (MBS 73240). This Medicare-funded cell-free DNA test predicts fetal RhD phenotype in eligible singleton pregnancies. This allows Anti-D prophylaxis to be targeted to women carrying an RhD-positive fetus. Testing can be performed from 11 weeks, but unless the fetus is predicted to be rhesus positive, repeat testing at 18 weeks is recommended in case of false negative. Many practices routinely test from 18 weeks instead. This represents an important step towards more personalised antenatal care while reducing unnecessary Anti-D administration.
Postnatal testing on cord bleed is then required to confirm the neonate’s rhesus status. It is important to note that this remains a screening test. Patients can decline testing or choose to receive anti-D regardless of the test result.
Key take-home messages
- Arrange ABO/RhD typing and antibody screening by 10 weeks’ gestation.
- Use 250 IU Anti-D following recommended first-trimester sensitising events.
- Routine Anti-D is not supported for medical termination before 10 weeks.
- If gestational age is uncertain, confirm with ultrasound and consider Anti-D.
- Consider fetal RhD genotyping (MBS 73240) to guide antenatal Anti-D prophylaxis in eligible women.
RANZCOG. Miscarriage, Recurrent Miscarriage and Ectopic Pregnancy Clinical Guideline. 2025, p. 72.
RANZCOG. Guidelines for the Use of Rh(D) Immunoglobulin (Anti-D) in Obstetrics (C-Obs 6). RANZCOG Guideline
National Blood Authority. Guideline for the Prophylactic Use of Rh D Immunoglobulin in Pregnancy Care. 2024. National Blood Authority Guideline
