Anti‐D Administration in Early Pregnancy ‐ Time for a New Protocol

NEED FOR NEW REGIMEN ‐ CLINICAL STATEMENT We accepted this paper for publication because the topic is important and we believe the matter needs to be resolved although it is really up to other authorities to decide how the problem should be solved. It is an interesting point to consider whether the NHMRC, The Royal Australian College of Obstetricians and Gynaecologists, the Commonwealth Serum Laboratories and/or the Health Department should have the responsibility of dictating a new clinical regimen which seems to be necessary in this case. It is certainly not the responsibility of the Australian and New Zealand Journal of Obstetrics and Gynaecology but we think it is appropriate for us to publish this information. The recent recommendation from the Royal Australian College of Obstetricians and Gynaecologists was to limit the use of anti‐D immunoglobulin to the following circumstances:1 Rh (D) negative women with no antibodies after delivery of an Rh (D) positive baby, with the dose being guided by a Kleihauer test. 2 Abortion, spontaneous or induced. 3 Genetic studies where transplacental access is needed or puncture of fetal blood vessels is performed 4 Trauma and antepartum haemorrhage on the basis of a Kleihauer test.Anti‐D immunoglobulin is no longer recommended after external cephalic version (unless there is a positive Kleihauer test), ectopic pregnancy, threatened miscarriage or prophylactically in the third trimester. This statement also made the point that there is a theoretical possibility for the transmission of the hepatitis or HIV viruses with administration of anti‐D immunoglobulin. This is no different from what occurred previously. What is different however is that patients are now asked to complete a consent form before receiving anti‐D immunoglobulin which highlights to them the possibility of infection with these viruses. It seems probable that many patients will now refuse to have anti‐D for any of the indications. A further comment is that we have not done all that is possible to obtain anti‐Dfmm volunteers in Australia. A discussion with the doctors in Melbourne who look after the small number of severely rhesus immunized patients who have received treatment in recent years indicates that none of them have been asked to volunteer to provide anti‐D. Summary: The use of anti‐D immunoglobulin has dramatically reduced the incidence of rhesus isoimmunization arising from pregnancy. A critical shortage of anti‐D has developed and consumption must be reduced, preferably without increasing the risk of isoimmunization. The standard dosage of anti‐D currently given at all gestational ages is 1 ampoule containing 125 ug of anti‐D. Of the anti‐D administered half is during the first trimester when a much lower dose could be used; 30 ug would remove from the maternal circulation the entire fetoplacental blood volume (3 ml) of a 12 week's pregnancy. A dose of 30 ug would also be adequate for most fetomaternal transfusions after 12 weeks but prior to the third trimester. A larger dose could be administered if maternal Kleihauer testing suggests the need for a supplementary dose. In the third trimester, the current regimen is appropriate ‐ a dose of 125 ug of anti‐D supplemented when needed on die basis of maternal Kleihauer testing. A lower dose ampoule of anti‐D should be available. In addition, existing protocols for anti‐D administration should be modified so that smaller more appropriate doses are given, better utilizing the limited supply of anti‐D.