Home » Transfusion practice » Obstetric transfusion » Pregnancy and Anti-D

Guidelines for the use of Rh(D) immunoglobulin in pregnant women with Rh(D)-negative blood group, and no pre-existing Anti-D antibodies

Routine Prophylaxis for All Rh(D)-negative Pregnant Women (Primigravida/Multigravida)*
Week 28 (Age of gestation) Week 34 (Age of gestation)
Rh(D) Immunoglobulin-VF Rh(D) Immunoglobulin-VF
625 IU Solution for intramuscular injection 625 IU Solution for intramuscular injection

Note: *Routine prophylaxis is recommended best practice; The doses at 28 & 34 weeks are given in ADDITION to any doses given for sensitising events.(1)

 

Best practice recommendations after a sensitising event:(1)

  • Rh(D) immunoglobulin should be administered as soon as possible after the sensitising event, but always within 72 hours for successful immunoprophylaxis.

  • If Rh(D) Immunoglobulin has not been administered within 72 hours, a dose offered within 10 days may provide protection.

Administration of Rh(D) Immunoglobulin for Each Sensitising Event*
Week 1 to Week 12
(first trimester)		 Beyond Week 12
(second & third trimester)		 Postpartum
Rh(D) Immunoglobulin-VF
(Single pregnancy)		 Rh(D) Immunoglobulin-VF
(Multiple pregnancy)		 Rh(D) Immunoglobulin-VF Rh(D) Immunoglobulin-VF
250 IU Solution for
intramuscular
injection		 625 IU Solution for intramuscular injection 625 IU Solution for
intramuscular
injection		 625 IU Solution for
intramuscular
injection

Notes: *Sensitising events include normal delivery, miscarriage, termination of pregnancy, ectopic pregnancy, chorionic villus sampling, amniocentesis, abdominal trauma, antepartum haemorrhage or external cephalic version; The batch number of every vial of human immunoglobulin administered must be recorded in the patient's medical history and in accordance with other legal statutory requirements; **In some circumstances, access to an intravenous preparation may be warranted. A quantity of intravenous Rh(D) immunoglobulin will be available for this purpose. Contact the Blood Service for more information.

  • To avoid wastage, Rh(D) Immunoglobulin should not be given to women with preformed anti-D antibodies, except where the preformed anti-D is due to the antenatal administration of Rh(D) Immunoglobulin.

  • Studies have shown that Rh(D) Immunoglobulin 100 IU is sufficient to protect against a Fetomaternal Haemorrhage (FMH) of 1.0 mL of fetal red cells (2.0 mL whole blood).

    • For example, Rh(D) immunoglobulin 625 IU is sufficient to protect against a FMH of 6 mL of fetal
      red cells (12 mL of whole blood).

  • Quantify the magnitude of the FMH following a sensitising event (including delivery) to ensure an adequate dose of Rh(D) Immunoglobulin is offered, as more than one dose may be required.

  • Tests to assess the volume of FMH include, but are not limited to, the Kleihauer-Betke acid elution test and flow cytometry.

  • The majority of fetal bleeds are less than 5 mL of red blood cells.

    • FMH is less than 0.05 mL in about 50% of cases

    • FMH is greater than 0.5 mL in about 5% of cases

    • FMH is greater than 1 mL in about 3% of cases

    • FMH is 30 mL or greater in up to 0.6% of cases

  • Approximately 15% of pregnant caucasian women will be Rh(D)-negative, and their babies [if Rh(D)-positive] may be at risk of developing Haemolytic Disease of the Newborn (HDN) due to Rh(D) incompatibility.

  • Antibody formation occurs during pregnancy in about 1%–1.5% of Rh(D)-negative women carrying a Rh(D)-positive infant, despite use of postnatal prophylaxis.

    • The rate of antibody formation can be reduced to 0.2% or less by the administration of Rh(D) Immunoglobulin during pregnancy, at 28 weeks and 34 weeks (antenatal prophylaxis), as well as after delivery.

 

References

  1. National Health & Medical Research Council. Guidelines on the prophylactic use of Rh(D) immunoglobulin (Anti-D) in obstetrics. Commonwealth of Australia, 2003.
Updated on 02 March 2011