medical negligence

What is informed consent for medical treatment?

Montgomery v. Lanarkshire Health Board [2015] A new Supreme Court decision regarding informed consent marks the end of the road for Sidaway.

The principle of informed consent

It is generally accepted that a patient has the right to make his/her own decision as to whether or not to undergo treatment having been provided with sufficient information on which to make that decision. This is known as ‘informed consent’, and any patient undergoing treatment must have provided this before such treatment is commenced. Such consent may be written on a consent form, provided verbally or, in some limited circumstances, implied. However, it is only ‘informed’ consent if the patient has been provided with all of the appropriate information required in order to make their decision.

By way of background

Informed consent in medical negligence cases has always been an area of uncertainty for medical negligence solicitors. However, there was a House of Lords decision in the mid-80’s that sought to clarify matters and in conjunction with subsequent cases has brought about the recognition of patient autonomy.

In Sidaway, Mrs Sidaway brought a claim against her spinal surgeon, after the procedure she underwent was unsuccessful and she became partially paralysed. Her claim was based on the argument that if she had been advised of the risk of catastrophic failure, she would not have given her consent for the surgery. It was her case that all information necessary for her to make an informed decision should have been given. The House of Lords applied the principles of the Bolam test, i.e. the information to be given to a patient prior to a procedure would depend on what an informed and responsible body of medical opinion would have thought was proper for the patient to know.

We understand that complaining about medical treatment can feel overwhelming and distressing, but there are many good reasons for making a complaint and possibly, in addition, a claim for negligence.

Slide-away Sidaway

Seven years after Sidaway, the Australian High Court in Rogers adopted the ‘material risk’ test. Ms Rogers was almost totally blind in her right eye and underwent surgery to improve her vision by removing scar tissue. Prior to surgery she specifically asked about the risks of the procedure, whilst the surgery was competently performed she developed sympathetic ophthalmia and was rendered almost totally blind. Whilst the risk was 1 in 14,000, it was material to her and the doctor was held to have been under a duty to inform Ms Rogers.

Back in the UK in the case of Pearce in 1999 it was held that in issues of consent it should be considered whether there is a ‘significant risk which would affect the judgment of a reasonable patient, then in the normal course it is the responsibility of a doctor to inform the patient of that significant risk, if the information is needed so that the patient can determine for him or herself as to what course he or she should adopt’.

Later in 2003 in the case of Wyatt, the consensus again was that doctors should have more consideration of the patient’s viewpoint and recognise ‘what is substantial and what is grave are questions on which the doctor’s and the patient’s perception may differ, and in relation to which the doctor must therefore have regard to what might be the patient’s perception’.

A greater emphasis on the patient’s specific needs and patient autonomy

In early 2015, in the case of Montgomery, the Supreme Court carefully reviewed the Sidaway judgement and post-Sidaway consent cases. The Supreme Court found that, over the years, the various post-Sidaway judgements had, in fact, significantly eroded the principle set out in Sidaway. Judges had been more inclined, over the course of time, to place less emphasis on what the ‘reasonable doctor’ would have done and placed increasing emphasis on the specific needs of the patient in each case.

The key facts of the Montgomery case are as follows

The claim involved the birth of a baby boy in 1999 who suffered oxygen starvation due to a traumatic delivery. As a result he sustained severe brain damage and there was subsequently a claim made on his behalf against the obstetrician. The basis of that claim was that Mrs Montgomery had not been given advised of the risk that, due to her being small and diabetic, there was a possibility that her baby would be large, which could lead to a difficult vaginal delivery (diabetes tends to lead to larger babies).

In the event, Mrs Montgomery was not made aware of this risk and proceeded to have a vaginal delivery. The baby was indeed on the large side and his shoulders became stuck in the birth canal; a condition called shoulder dystocia. As a result of this there was a 12 minute delay in delivering baby Montgomery, as a result of which he suffered brain damage and paralysis to one of his arms due to the force being applied when pulling him out.
Mrs Montgomery’s case was that she should have been warned of the fact that her baby could be on the large side and that this could give rise to the risks of shoulder dystocia and associated complications during a vaginal delivery. Her evidence was that, had she been aware of these risks, she would have asked for a caesarean section, which ought to have been offered.

The Defendant’s case was that the obstetrician had not made Mrs Montgomery aware of the shoulder dystocia risks because the risks of a serious complication arising were very small. In other words there was no sense in worrying the patient about a serious complication if said complication is very unlikely to occur. This position was supported by several experts at Trial.

Based on the principle as borne out by the majority decision in Sidaway, the Defendant’s case was arguably the positon that the court would have preferred. Indeed, the Scottish courts at first instance (this was a claim originating in Scotland) initially found in favour of the Defendant on the basis that the Sidaway principle applied, i.e. it was a decision for the reasonable doctor to make and in this case it was not ‘unreasonable’ for the obstetrician not to have warned Mrs Montgomery of the small risk associated to a large baby and shoulder dystocia. 
The Claimant appealed the decision and the case went all the way to the Supreme Court to be decided.

The ‘reasonably prudent patient’

The Supreme Court clarified that a doctor must respect the right of the patient to make their own informed decisions about their treatment. If the treatment offered or recommended involves material risks which a reasonably prudent patient would think significant, then that patient ought to be made aware of them.

The Supreme Court judgement states:

“…patients are now widely regarded as persons holding rights, rather than as the passive recipients of the care of the medical profession.”

Some people may argue that the Montgomery judgement goes so far as to undermine a doctor’s skill and position by suggesting that patients are better placed to decide what treatment is best for them. What the court has made clear is that doctors cannot presume to know what information is relevant to a patient and what information they can go without. Different patients have different needs and a reasonably prudent doctor ought to know what level of information their respective patients need; what suits one patient may not suit another.

Accepting risks and the ‘therapeutic exception’

The Montgomery judgement asserts that the doctor/patient dynamic should be such that doctors treat their patients as adults who are capable of understanding that medical treatment cannot be certain of success and is not without risk. Such patients are capable of making informed decisions regarding their treatment, accepting the risks involved and the consequences if the outcome of the treatment is not as they had anticipated.

The court did, however, provide a caveat known as the therapeutic exception, which allows a doctor to withhold information from a patient if divulging that information would put that patient’s personal health at risk. The court stressed, however, that this was a very limited exception.

So what was the Montgomery decision?

The Supreme Court ruled that the obstetrician should have warned the mother about the risks associated to a large baby and shoulder dystocia, and discussed the alternative of an elective caesarean section. Failure to do so was a failure to properly inform the patient and therefore she could not have provided informed consent.

The next key issue is that of causation – can the Claimant show that damage/injury would have been avoided or lessened but for the failure of the doctor to provide all information necessary to obtain informed consent?

The court appeared to accept that not every woman could be offered a caesarean section if there was a very small risk of complications arising during birth; indeed, there are risks associated to every birth. However, the court combined the evidence of the Defendant and the evidence of the Claimant and concluded that on the balance of probabilities, on the facts of this case, the Claimant would have opted for a caesarean section. That being the case, the baby would have avoided the shoulder dystocia.

Post-Montgomery decisions

The first Decision in the post Montgomery era was FM v Ipswich Hospital NHS Trust - the Montgomery decision was handed down during the trial. FM was born with severe shoulder dystocia in 2002, his older brother had also been born with a moderate degree of shoulder dystocia 6 years earlier but Mrs M was not informed of this. It was held that ‘had she had the information she should have had, would plainly have wanted to understand what risks there were’ and would have subsequently elected for a caesarean section.

Mrs A v East Kent Hospitals University NHS Foundation Trust, decided on 20 April 2014, sought to clarify the scope of Montgomery and what a patient should expect to be told. Mrs A alleged that the defendant Trust failed to warn her of the risk of chromosomal abnormality during her pregnancy and had she been told of the risk she would have proceed to a termination at 32 or 35 weeks gestation. It was found that from the evidence available at the time that the risk was 1 in 1000. The Honourable Mr Justice Dingemans in his findings stated that “the decision in Montgomery affirms the importance of patient autonomy… and the proper approach set out in Pearce and Wyatt. It is not authority for the proposition that medical practitioners need to warn about risk which are theoretical and not material.” In his conclusion the Claimant’s claim was dismissed on the basis that there was “no material risk that B was suffering from a chromosomal abnormality. There was the background of risk but there was nothing to suggest that was a risk to which a reasonable patient, in the position of Mrs A, or Mrs A herself, would have attached any significance.”

In David Spencer v Hillingdon Hospital NHS Trust it was found that the Defendant was negligent in failing to warn the Claimant of the risk of developing a DVT following surgery. His Honour Judge Collender QC commented that “Montgomery is clearly a decision which demonstrates a new development in the law as it relates to the law on informed consent and strictly the ratio decidendi of the decision is confined to cases involving the adequacy or otherwise of information given to a patient upon which they are to decide whether or not to undergo a particular type of treatment.” When summarising his conclusions His Honour Judge Collender QC went on to say “In light of the Montgomery decision… I would express the test that I should apply to be the Bolam test with the added gloss that I should pay regard to what the ordinary sensible patient would expect to have been told. Put in the form of a question, the test I consider to be, would the ordinary sensible patient be justifiably aggrieved not to have been given the information at the heart of this case when fully appraised of the significance of it?”


In summary, it is no longer acceptable that the decision as to the level of detail shared with the patient rests solely with the doctor. Instead, doctors ought to consider the specific needs and circumstances of their respective patients and advise them accordingly.

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Chat to the Author, Janine Collier

Executive Partner, Medical Negligence, Cambridge office

Meet Janine
Janine Collier, partner, medical negligence specialist & cerebral palsy claims solicitor in Cambridge
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