Patients to be warned of risks to help them make informed decisions

Last week, the Supreme Court gave a decision that has redefined the law on informed consent to medical treatment. The Court was considering the case of Mrs Montgomery, whose son was born in 1999 with Erb’s Palsy and Cerebral Palsy as a result of his shoulders getting lodged in the birth canal during delivery – a condition known as shoulder dystocia. The baby was starved of oxygen and suffered severe brain damage and an injury to the brachial plexus during the delivery.


Babies born to diabetic mothers at risk of shoulder dystocia


The facts of this case are extremely sad. Mrs Montgomery has diabetes; it is well known that diabetic mothers are likely to have large babies. Because of this, there is a 9-10% risk of shoulder dystocia occurring during delivery. Shoulder dystocia is an obstetric emergency requiring intervention, the consequences of which give rise to further risks for both the baby and the mother.


Shoulder dystocia – the consequences


In delivering the baby’s body, the use of force can cause an injury to the brachial plexus, causing a condition known as Erb’s Palsy. Children with Erb’s Palsy suffer differing degrees of loss of function of the arm and hand, sometimes the loss of function is complete. The Court heard that the risk of Erb’s Palsy in a diabetic pregnancy is 0.2%.


A further risk to the child is that, the umbilical cord (on which the baby relies for oxygen) can be compressed by the shoulder. This leads to the baby suffering a lack of oxygen, causing Cerebral Palsy or even death. The Court heard that the risk of this happening in a diabetic pregnancy is less than 0.1%.


For the mother, there are risks of post partum haemorrhage and fourth degree perineal tears, estimated at 11% and 3.8% respectively.


Mrs Montgomery not told of the risks nor offered a Caesarean Section

The obstetrician treating Mrs Montgomery knew of the risks but decided not to warn Mrs Montgomery or to offer her the solution that would have avoided those risks – a Caesarean Section. She did so because she considered the risks to be small and that, if she warned diabetic mothers of the risks, they would all want a Caesarean Section. In the obstetrician’s opinion, she did not think it was in the maternal interests to opt for a C-section instead of vaginal delivery.


Initial claim for medical negligence unsuccessful


Tragically, Mrs Montgomery and her son suffered severely because of this decision. A medical negligence claim was brought on the basis that she should have been warned of the risks and offered a Caesarean Section, which she would have accepted, and so her child would have avoided both Erb’s Palsy and Cerebral Palsy.


The Claim failed both at trial and at the first appeal, because the Courts applied the established test – the Sidaway2 test – in which it has been considered not negligent to fail to warn of a risk if there is a reasonable body of medical opinion that would also have not warned of the risk. This test has been used in the consideration of medical negligence cases since 1985.


Supreme Court overturns decision and says doctors must inform patients of significant risks


The Supreme Court considered the Sidaway test and the changes in society in the intervening 30 years. They decided that patients were entitled to be told of the material risks involved in any recommended treatment and of any reasonable alternative or variant treatments. Therefore, a doctor must warn of any risk that a reasonable person might consider to be significant, or a risk that they know or should know that the particular person would consider significant.


However, proving that the patient should have been warned is not enough. The Claimant still has to prove that, had they known of the risk, they would have made a different choice or at least would not have proceeded with the treatment on that day. In this case, the evidence showed that, had she known the risks of a vaginal delivery, Mrs Montgomery would, indeed, have chosen a Caesarean Section.


Commenting on the judgment, specialist medical negligence solicitor Alan Mendham said “In making this decision, Mrs Montgomery’s obstetrician chose not only which risks to inform her of, but also chose the risks that Mrs Montgomery and her child would be exposed to.


“The Supreme Court have made a landmark decision that gives the patient more say in their medical treatment.”



At Gadsby Wicks, we have achieved successful outcomes for families who have suffered because of a mis-handled birth. See here for a selection of our case studies involving birth injuries.


If this has happened to you or someone you love, our expert lawyers can help. Please contact us on 0800 321 3112 or email us here to make an enquiry.



1  Montgomery –v- Lanarkshire Health Board [2015]

2  Sidaway –v- Board of Governors of the Bethlehem Royal Hospital and the Maudsley Hospital


Posted 16th March 2015 | Posted in News,Uncategorised