Authors' reply: Guidance on anti-D administration in early pregnancy

Authors


Authors' reply

Sir,

Dempsey and Overton[1] draw attention to the change in advice given in the recent National Institute for Clinical Health and Excellence (NICE) guidelines. These are largely consistent with the revised British Committee for Standards in Haematology (BCSH) guideline for the use of anti-D immunoglobulin in the prevention of haemolytic disease of the fetus and newborn.[2] This recommends that anti-D prophylaxis is not necessary in cases of spontaneous complete miscarriage or mild painless vaginal bleeding before 12 weeks of gestation, or in cases of threatened miscarriage with a viable fetus where bleeding completely stops before 12 weeks. The BCSH is a subcommittee of the British Society of Haematology, formed in 1964, and produces up-to-date guidelines by a rigorous process involving all relevant stakeholders and a wide range of experts for both clinical and laboratory haematology. These are freely available and regularly updated (see www.bcshguidelines.com) and currently include 17 published in the area of transfusion (four relevant to obstetrics) since 2001. The BCSH authors note the NICE guidance on ectopic pregnancy,[3] but consider that in view of the significant risk of sensitisation in such cases, and the lack of evidence base for the NICE recommendation, anti-D should continue to be administered to RhD-negative women with ectopic pregnancy regardless of the mode of management.

Over the last 15 years the UK national confidential haemovigilance scheme Serious Hazards of Transfusion (SHOT; www.shotuk.org) has asked reporters who submit cases of delay or omission of anti-D prophylaxis for follow-up information to inform estimates of the rate of sensitisation but this is rarely provided, possibly because clinical staff do not wish to raise awareness that there has been an error. We therefore do not have any data about risks of sensitisation from events in the first 12 weeks of gestation or at other times later in pregnancy or delivery.

There are some observations that the current scheme for prophylaxis may result in undetectable levels of anti-D at delivery and that this could result in sensitisation.[4] Therefore, from January 2013 we are asking reporters to submit cases where a new immune anti-D is detected for the first time in a pregnancy, then looking back in order to determine possible sensitisation events or suboptimal prophylaxis with anti-D immunoglobulin. NICE have recognised in their guidance that there is little harm associated with the provision of anti-D immunoglobulin prophylaxis and that there is a clear health benefit in avoiding sensitisation if possible—and the BCSH authors' approach is that it is better to be ‘safe than sorry’.

Disclosure of interests

None.

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