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Material risks

The General Medical Council makes it clear that a well established risk of serious adverse outcome is significant for the purpose of obtaining consent. It is also clear from Montgomery that what constitutes a material risk depends on the facts and characteristics of each patient’s clinical situation. In the case of Mrs A v East Kent Hospitals a baby had been delivered early due to her poor intrauterine growth. During the pregnancy, the underlying diagnosis was thought to be placental insufficiency, but examination of the baby revealed signs of severe disability. Only postnatally was the baby’s unbalanced chromosomal translocation diagnosed. Her mother claimed that a chromosomal cause should have been suspected on the basis of her poor intrauterine growth. She said that if a chromosomal anomaly had been suspected, she would have had amniocentesis, and if chromosomal anomaly detected, a termination at 32 or 35 weeks of gestation. She claimed that this was a case of ‘wrongful birth’.

The court found that there was no material risk to which Mrs A should have been alerted. The risk of a chromosomal abnormality underlying her baby’s poor growth was a ‘…theoretical, negligible or background risk of no more than about 1:1000, to which a reasonable person in Mrs A’s position would not have attached significance. Mrs A’s ‘position’ was based on her evidence that she would not have attached significance to the ‘background risk’ of Down’s syndrome, calculated in her case at 1:1700. She made it clear to the court that she did not consider that magnitude a real risk.

The court found that even if she had been warned of chromosomal abnormality she would have ruled out amniocentesis (the next stage in diagnosis) because of the associated much higher risk of precipitating preterm delivery, and its attendant complications. Montgomery requires the doctor to consider whether the particular patient would be likely to attach significance to a foreseeable risk. The facts and characteristics of Mrs A’s case provide an explanation as to why the court had to conclude that she regarded a risk of 0.1% as insignificant, thus fatally undermining her own claim.

But this case is not an authority for the proposition that a risk of 0.1% cannot be considered as material - in other words, as significant to the patient who has to make a decision concerning treatment. Many procedures, for instance those involving the spinal cord, involve risks that rarely crystallise into physical harm. But the possibility that a neurological injury could occur, however unlikely that might be, may well persuade a patient to resist the temptation to consent to treatment.

When considering elective procedures, particularly one where the option of no treatment at all remains realistic, rare risks could therefore be regarded as material. This plainly has consequences for clinical practice. Perhaps the time has come for speciality associations to consider the evidence for what constitutes a ‘risk’ associated with the performance of their repertoire of interventions. Those procedures conferring negligible tangible clinical benefit could be addressed first, since it is these in which rare adverse outcomes will exert the greatest persuasion to avoid treatment altogether. But quite how a long list of potential rare risks can realistically be communicated to the patient in front of you requires further consideration.

Robert Wheeler

Department of clinical law, February 2018