Hogg v The Secretary of State for Health

A claimant alleging injury from a medical procedure must prove, on the balance of probabilities, that the procedure caused the injury. The claimant need not establish a particular causal mechanism, but must prove that some mechanism triggered by the procedure caused the condition. Where competing medical hypotheses remain possible, the court must assess the evidence as a whole, including the rarity of the alleged injury and whether each hypothesis explains the clinical findings. A negligent failure to assess gestational age did not establish liability where causation was not proved. Proceeding with a second aspiration after a bloody amniocentesis sample was not negligent where that practice accorded with a responsible body of medical opinion at the relevant time.

The claimant, a protected party, alleged that his septo-optic dysplasia and associated brain abnormalities were caused by an amniocentesis performed on his mother in 1985. The claim against the defendant, who was vicariously liable for the hospital staff, was tried on liability alone.

The issues were whether the gestational age had been assessed negligently; whether the procedure had been performed with real-time ultrasound and, if not, whether a further scan was required after a bloody first aspiration; and whether the claimant’s abnormalities were caused by the amniocentesis needle. The court found that the gestational age had been assessed negligently, but rejected the allegations concerning the method of performing the procedure and determined that causation had not been established.

1. Gestational age. The sonographer had no proper basis, on the measurements recorded, for stating that the gestational age was at least 16 weeks. The assessment was negligent, and the defendant was vicariously liable for that negligence. Had the correct gestational age been reported, the procedure would have been postponed.
2. Method of amniocentesis. The evidence established that the 1985 procedure was performed after a preliminary scan, but without real-time ultrasound during needle insertion. The claimant’s parents’ sincere recollection of seeing the needle on the screen was mistaken. The evidence did not establish that the doctor was negligent in proceeding with a second aspiration after the first sample was bloody. Bloody taps were common at the time, and proceeding to obtain a second sample was consistent with a responsible body of medical opinion.
3. Causation. The claimant bore the burden of proving, on the balance of probabilities, that the amniocentesis caused his abnormalities. He did not have to prove one particular mechanism, but had to show that a mechanism triggered by the procedure, alone or in combination, caused the abnormalities. The competing evidence left both traumatic and intrinsic developmental causes possible. The traumatic theories did not satisfactorily explain the diverse abnormalities, their development at different stages, the absence of a clear injury track or the absence of an expected skin lesion. Although the relevant genetic cause was unidentified, an inherent developmental cause was more likely on the evidence.
4. The claimant therefore failed to establish causation. The claim was dismissed.