Montgomery v Lanarkshire Health Board [2015] UKSC 11
Montgomery v Lanarkshire Health Board is the modern leading case on informed consent. It replaced medical paternalism with a duty centred on the patient's right to decide between treatment options.
Facts
Nadine Montgomery was pregnant, of small stature and had diabetes. Diabetes increased the chance of shoulder dystocia during vaginal delivery to about nine or ten per cent. Her consultant knew that Mrs Montgomery was worried about giving birth naturally but did not explain the dystocia risk or offer detailed advice about caesarean delivery. The consultant considered the risk of serious injury to the baby to be very small and said that routinely warning diabetic mothers would lead most to request caesareans. During vaginal delivery, shoulder dystocia occurred. The baby was deprived of oxygen and was born with severe disabilities. Mrs Montgomery alleged that, if properly advised of the material risk and reasonable alternative, she would have chosen a caesarean section and the injury would have been avoided.
Legal Issue
What must a doctor disclose for a patient to make an informed treatment choice, and was that duty governed by responsible medical opinion under Bolam?
Held
The Supreme Court allowed Mrs Montgomery's appeal. Doctors must take reasonable care to ensure that patients are aware of material risks inherent in recommended treatment and of reasonable alternatives or variants. A risk is material if a reasonable person in the patient's position would probably attach significance to it, or if the doctor knows or should reasonably know that this particular patient would do so. The assessment is not controlled by whether a responsible body of doctors would have withheld the information. Dialogue is required so that the patient can understand the choices, although the doctor need not discuss risks that are unknown and may withhold information in narrowly defined therapeutic circumstances. The dystocia risk and caesarean alternative were material, and proper advice would have led Mrs Montgomery to choose a caesarean. Causation was established.
⭐ Legal Principle
A doctor must take reasonable care to make a patient aware of material risks in recommended treatment and reasonable alternatives. Materiality is judged from the perspective of a reasonable person in the patient's position and from what the doctor knows, or should know, matters to that individual patient.
Significance
Montgomery marks a decisive shift from doctor-led disclosure under Sidaway towards patient autonomy and shared decision-making. Bolam still informs technical diagnosis and treatment decisions, subject to Bolitho, but does not determine what information a patient needs to choose. The duty is one of reasonable dialogue, not a demand to list every remote possibility. Later cases emphasise that claimants must still prove causation, normally by showing that proper advice would have changed their decision or the timing of treatment. The judgment applies throughout UK medical-negligence teaching despite arising from Scottish proceedings. McCulloch v Forth Valley Health Board adds that whether an alternative treatment is reasonable is a matter of professional judgement, while disclosure of material risks attached to a reasonable alternative remains patient-centred.
Common exam questions about this case
When is a treatment risk material under Montgomery?
A risk is material where a reasonable person in the patient's position would probably regard it as significant, or where the doctor knows or should reasonably know that this particular patient would regard it as significant. Probability is relevant but not decisive. The seriousness of the possible outcome, available alternatives and the patient's expressed concerns may make even a relatively small risk material.
Why did the Supreme Court reject a Bolam approach to disclosure?
Choosing treatment concerns the patient's autonomy rather than a purely technical medical judgement. The profession cannot decide for patients which risks they are entitled to know merely because a responsible body would withhold the information. Doctors contribute medical expertise, but patients decide which risks and benefits matter to their own lives after reasonable explanation of the options.
Does Montgomery require doctors to disclose every conceivable risk?
No. The duty concerns material risks and reasonable alternatives, communicated through reasonable dialogue. Doctors are not expected to overwhelm patients with every remote or theoretical possibility. The judgment also recognises a narrow therapeutic exception where disclosure would be seriously detrimental to the patient's health, but this cannot be used simply because the doctor thinks the patient might choose an option the doctor considers unwise.