A review of maternal alloimmunisation to Rh D in Northern Ireland

To estimate the current incidence of maternal sensitisation to Rhesus (Rh) D in Northern Ireland, examine adherence to recommendations for administration of anti-D immunoglobulin and identify potential causes for all cases of anti-D alloimmunisation sensitisation from January 2010 to September 2015.

Post-partum anti-D immunoglobulin administered to Rh D-negative women and routine antenatal anti-D prophylaxis have greatly reduced the incidence of haemolytic disease of the fetus and newborn due to immune anti-D. Despite these measures, anti-D alloimmunisation sensitisation continues to occur, albeit much less frequently than in the past.

This was a retrospective review of new sensitisations to Rh D detected in antenatal records between January 2010 and September 2015 in Northern Ireland. A review of patient notes and laboratory data was carried out to examine adherence to standards and identify potential causes of sensitisation.

A total of 67 new sensitisations to Rh D were identified over a 69-month period, and the sensitisation rate for the full calendar years 2010-2014 was 0·310%. Only 4% of cases appear to have been preventable, with two cases involving failure to adhere to guidelines.

A total 96% of sensitisations occurred despite full compliance with guidelines. In a large proportion, sensitisation occurred following delivery (51%). A change in practice in Northern Ireland is under consideration to increase the dose of anti-D immunoglobulin given following delivery from 500 to 1500 U in an attempt to reduce these sensitisations.