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High Court delivers judgment in obstetric case relating to care provided in 1996

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By Mark Ashley & Ciaran Claffey


Published 24 January 2023


On 11 January 2023 Mr Justice Ritchie handed down judgment in the case of CNZ v Royal Bath Hospitals NHS Foundation Trust. The case relates to obstetric care that the Claimant’s mother received 27 years ago.  The judgment is important for a number of reasons including:

  • The Montgomery decision on informed consent applies to care given in 1996;
  • It does not only apply to discussions in planned consultations but it also applies to care given in the delivery suite and operating theatre;
  • In cases concerning profound hypoxic-ischaemic brain injury, a defendant will be liable for 100% of that injury unless it can show that some specific degree of injury was unavoidable;
  • But in this case it was not possible to demonstrate the functional impact of any unavoidable injury and so the Defendant  was liable for 100% of the injury.

Facts and allegations

The case relates to obstetric care that was provided to the Claimant’s mother in 1996, when she was pregnant with twins. On a number of occasions the Claimant’s mother requested a caesarean section but this was declined by those treating her.

The mother was admitted for the induction on 2 February 1996.    At 00:01 on 3 February 1996 the first twin (the Claimant’s sister) was delivered vaginally, but the Claimant’s head remained high in the pelvis.  A decision was made at 00:35 to transfer the mother to theatre for artificial rupture of membranes (“ARM”).  In theatre the mother stated that she did not want to have ARM and so a decision was made to proceed to caesarean section.  The Claimant was delivered by caesarean section at 01:03.  She was in poor condition and was subsequently diagnosed with quadriplegic cerebral palsy.

Essentially the Claimant’s case is that had her mother’s views on caesarean section been taken into account then this would have been offered earlier. If this had happened she would have been delivered sooner and would have escaped harm.

The Judge’s Findings on the Standard of Care

The allegations involve a similar topic to those which were considered in Montgomery v Lanarkshire Health Board; obstetric care and the extent to which autonomy of the expectant mother is taken into account. Ever since the decision of the Supreme Court in Montgomery in 2015 there has been much discussion in the medical and legal communities as to the extent to which the law regarding informed consent that was set out in that judgment can be applied to historical cases.  In this case Mr Justice Ritchie tackled this issue directly.  He commented that “I doubt it can be taken as far back as the 1950s or 1960s”, and he questioned whether it could be applied to clinical practice in the 1980s.  However, he decided that, although he was troubled by whether it could be applied to clinical practice in 1996, he decided that “it probably does”.  He did raise the possibility of whether perhaps “a watered down form of the ruling would have applied or whether a tapered growth of the Montgomery duty to consent properly could be the correct approach in 1996”, but he said that he could not adopt any such approach “without an indication for such in the Supreme Court’s judgment”

In this particular case, the key findings concern events from 00:25 on 3 February 1996 (38 minutes before the Claimant was in fact delivered).  At that time the CTG trace was mainly reassuring, but, for various reasons that Mr Justice Ritchie sets out at paragraph 297 of the judgment, there were problems with trying to do an ARM first (including that the mother was opposed to ARM and epidural anaesthetic, the registrar was not experienced in performing “high” ARMs, and it was getting closer to the 30 minutes that it should usually take to deliver the second twin).

The judge found that the mother wanted to proceed to a caesarean section, but the registrar ignored her wishes and adopted an approach (to progress towards undertaking a ARM) that was “too paternalistic”, contrary to Montgomery principles.

The judge also found that there were delays in transferring the mother to theatre, because, despite the fact that the usual 30 minutes that is considered normal for delivery of the second twin was about to elapse (and did elapse at 01:01), there was a lack of urgency on the part of the registrar.

Taking all of this into account, the judge decided that the Claimant should have been delivered by 00:56.5 (i.e. 6.5 minutes before she was in fact delivered).


It was agreed by the parties that the Claimant suffered an acute profound hypoxic-ischaemic insult that ended when she was resuscitated at 01:06, five minutes after she was delivered.  The judge decided that the insult probably lasted 16 minutes, and therefore that it started at 00:50.  It was accepted by both parties (in accordance with the conventional understanding of the science relating to acute profound hypoxic-ischaemic insults) that the first 10 minutes would not have caused brain damage and therefore, given that the judge decided that the Claimant should have been delivered by 00:56.5, the Claimant succeeded in proving causation on a “but for” basis.  In other words, on the balance of probabilities, but for the breaches of duty, she would have been delivered in the first 10 minutes of the insult and so would have avoided brain damage. 

However, there had been considerable argument in the case about the extent to which causation could be decided on a “material contribution” basis (this being where the law awards 100% compensation to a claimant who, in certain circumstances need only show that the negligence materially contributed to the harm they suffered rather than caused all of it), and therefore the judge gave his views on that issue.

First, the judge found that each minute of hypoxia after the first 10 would make a contribution to the injury. Putting that into context: a Claimant experiences 12 minutes of hypoxia, the first 10 are generally thought to be not damaging, the 11th minute is damaging but could not be avoided, but because of negligence the 12th minute occurred. In such a case, even if it is felt the Claimant might have had some brain injury in any event, the claimant recovers 100% compensation for the entirety of their brain injury (unless, potentially, the functional nature of the injury that would have occurred in any event can be defined).

Second, the judge seemed to recognise the inherent unfairness of this outcome so went on to consider whether damage could be apportioned. For example, in the 12 minute example one might say the fair outcome would be to award the claimant 50% of the overall value of the claim, reflecting the fact that 50% of their exposure to damaging hypoxia was negligent and the other 50% was not.

A number of approaches were considered here, for instance the theory proposed by a leading paediatric neurologist which proposed that each 5 minute period was likely to result in a specific type of harm. That theory (the “aliquot theory”) was rejected because of a lack of sufficient certainty in the evidence as to the functional outcome for an individual who experiences unavoidable damaging hypoxia.  What’s more, the judge could not apportion based on the duration of negligently caused exposure because, again, there was no evidence which might support doing so.

In the absence of such evidence the Courts will continue to find it difficult to do anything other than award the Claimant full compensation when some unavoidable hypoxia made an undefined contribution to the outcome..


Some of the most important points arising out of this judgment for defendants in clinical negligence claims are as follows:

  • Even though this case related to care given to the mother almost 20 years before the Montgomery judgment, and even though the mother was advised against undergoing caesarean section, the judge decided that the advice that the mother was given antenatally did comply with the principles set down in Montgomery. This shows that concern about whether Montgomery retrospectively applies too high a bar for clinicians might be overstated.
  • The judgment confirms that the obligation to properly discuss risks and alternatives with mothers does not end when the mother goes into labour. Clinicians must continue to be mindful of ensuring that the appropriate discussions take place and informed decisions are made as the labour evolves. 
  • The judge’s comments about the applicability of the doctrine of material contribution to cases involving acute profound hypoxia were obiter and therefore will not necessarily be applied in future cases. Furthermore, they do not amount to new law rather they are a reflection of pre-existing decisions from appellate courts. Ultimately, any definitive statement of the law in this regard might require a Supreme Court decision. 
  • The judgment leaves open the possibility of apportioning damages where the evidence enable findings to be made as the functional nature of the disability which would have occurred in any event.
  • It must be noted that this is a first instance decision which may be subject to appeal and many of the comments discussed above were obiter.