‘Take 12 people. Immerse them in a subject for 2 days. Mix in new research, background papers, expert opinion and feedback from conference delegates until agreement has been reached. Widely distribute the resulting final consensus statement.’

A recipe for success? Certainly few could have had any idea before the conference that the panel would come down so strongly in favour of antenatal anti-D prophylaxis for all Rhesus D-negative women. As one delegate said:‘You are to be congratulated for coming off the fence.’ Perhaps that leap could only ever have been made at a meeting like this, with the panel able to consider all the available evidence while at the same time standing back and taking the wider view.

The first challenge for the panel was to arrive at a statement on the scale of the problem. This was not easy, particularly as there were signs of widespread and serious under-reporting. Indeed a review of maternal case notes in Scotland suggested the number of fetal losses attributable to RhD disease was five times that recorded by the Registrar General. In clarifying this issue the panel made much use of its access to expert opinion. In this way a consensus was reached, but the lack of consistent evidence is reflected in the final wording: ‘In the 1990s pregnancy loss and death in the first week of delivery due to RhD alloimmunisation is in the order of 50 per year in the UK.’

The panel was well aware then that, at least in terms of mortality, RhD alloimmunisation is a relatively small problem. But it is also easily preventable. However research presented at the meeting consistently showed that the existing guidelines —recommending anti-D IgG for RhD-negative women after sensitising events in pregnancy and the birth of a RhD-positive infant—were not being fully applied. Among these studies was a survey of A&E departments in England and Wales that showed that more than three-quarters had no policy on administering anti-D to RhD-negative women and were not giving it when indicated. An audit of anti-D sensitisation in Yorkshire also concluded:‘Failure to adhere to published protocols for the administration of anti-D IgG occurred in a significant proportion of women who subsequently developed immune anti-D’. Although well aware of the limitations of any guidelines, the panel felt that this underuse was unacceptable. It was apparent that some units were not even aware of the existence of the guidelines, published in 1991.

Adequate dissemination of the revised advice this summer will therefore be crucial to improving the situation. An area of contention arose during presentation of the first draft of the consensus statement to the conference delegates. The panel had recommended a change to the 1991 Guidelines based on expert opinion and background papers—namely that it was not necessary to give anti-D IgG if threatened miscarriage occurs and resolves before 12 weeks, and when spontaneous miscarriage without instrumentation occurs before 12 weeks. This prompted much debate between panel and delegates, and in the time available it was clear that no agreement was going to be reached. This unfortunately meant the recommendation was dropped from the final statement, replaced by a question about the need for anti-D IgG in the first trimester: a case of lack of time beating the panel over an issue that has huge workload implications for healthcare professionals.

And so to universal antenatal prophylaxis. It became apparent that improving adherence to the Guidelines would only be a partial solution, and that a significant proportion of women would still become sensitised by small undetected bleeds from the fetus. A typical example came from a review in Sheffield that showed that the isoimmunising event was only clearly recognised in fewer than one in six affected pregnancies. The researchers concluded: ‘The absence of a clear isoimmunising event in many cases raises the question of routine immunoprophylaxis’.

Supply of anti-D IgG was considered in depth. Specialists at the Regional Transfusion Centre in Aberdeen reported that increased boosting of existing donors could meet the demands for antenatal prophylaxis for RhD-negative primigravidae, but offering anti-D IgG to all RhD-negative pregnant women would require recruitment of new donors. The panel were, however, particularly impressed by a presentation from the London and South East Zone of the National Blood Service, which showed how a systematic and personal approach to donors led to a significant increase in procurement of anti-D IgG. Similarly the panel found no reason, from either new research or background papers, to rule out routine antenatal anti-D prophylaxis on the basis of cost. The decision was getting easier.

After reviewing all the evidence the panel was united in agreement of the need for universal antenatal anti-D prophylaxis for RhD-negative women. The ‘for and against’ debate on the first day of the meeting summarised well the arguments on each side. A key argument against concerned the need for a definitive trial, in a bow to the ideal of evidence-based medicine. The panel considered this but felt that it would only provide an excuse to further delay widespread introduction of a policy known to be of proven benefit. Interestingly, and to the surprise of at least some of the panel members, there was no argument from the conference when the draft consensus statement was presented, suggesting the decision to recommend universal antenatal anti-D prophylaxis was roundly supported.

An earlier suggestion that the policy should be restricted to RhD-negative primigravidae, in whom the benefits might be greatest, was considered but dismissed by the panel. No convincing ethical or economic argument could be found for limiting the policy to this group of women.

Details such as the dosage and schedule of prophylaxis aroused much debate, both among panel members and delegates. The panel finally decided that it was not in its remit to be prescriptive, feeling that a better place for this would be in the revised recommendation document. Instead the most popular options were mentioned.

Overall the panel members were happy with the final consensus statement. There was certainly a sense that we had achieved something worthwhile, in producing a statement which was likely to prove influential on practice. With that sense of achievement was also a sense of responsibility. It is only fair to say that no panel member left any stone unturned when considering the evidence.

Lack of time was a double-edged sword. It meant, for example, that the panel was not able to provide details of the levels of evidence which backed up the recommendations in its statement. And as discussed above it did lead to some compromise on our part over certain issues. But it also meant that procrastination was out. The panel knew what it had to do in the 2 days, and did it. Nobody can really ask for more and hopefully the end result speaks for itself.

  1. [Paul Haines is the Science Editor of Doctor and Hospital Doctor.]