The clinical context
On the Panel’s summary of the record, Baby M was a twin boy born at 33 weeks and 2 days weighing 1.703 kg, with severe intrauterine growth restriction, delivered by elective Caesarean section for oligohydramnios and growth restriction of the first twin. He was born breech and was bagged at birth for being slow to pink.
He was plethoric (haemoglobin 190), jaundiced (serum bilirubin 57, above the phototherapy threshold) and hypoglycaemic (blood sugar 1.9). He was treated for possible sepsis with antibiotics, and with phototherapy. His white cell count and CRP were not raised.
The four hours before the collapse
This is the part of the record that the “sudden collapse” framing leaves out. At 1215 the next day, Baby M developed a fever, which subsided with a change in environmental temperature; increased work of breathing; a distended abdomen; and bile-stained nasogastric aspirates. The nurse was concerned enough to call the registrar, who stopped his feeds and put the nasogastric tube to free drainage.
Four hours later, Baby M developed apnoea with desaturation and a low heart rate. He was resuscitated: cardiac massage, six doses of adrenaline, two of bicarbonate, two of saline, intubation and ventilation. Two of the adrenaline doses were given before his airway was secured. He stabilised, was extubated the next day, and was discharged home at a month of age. A Eustachian valve was detected on his cardiac echo.
The prosecution theory
It was alleged that air was injected into Baby M’s intravenous system, causing air embolism and collapse. The jury convicted on attempted murder.
What the Panel found
The Panel’s reading starts from the four hours the prosecution narrative skips. Baby M had signs of possible sepsis from birth — jaundice requiring phototherapy and hypoglycaemia — and was on antibiotics for it. He then deteriorated for four hours before the collapse, with abdominal distension, increased work of breathing, a raised temperature and bile-stained aspirates, all of which were of enough concern to the nurse and registrar that they acted on them.
The Panel concludes that the acute episode of desaturation and bradycardia was likely triggered by apnoea from sepsis, abdominal distension with ileus, and prematurity. It could also be due to the cardiac Eustachian valve found on his echo, which can cause episodes of desaturation and bradycardia through intermittent right-to-left shunting of blood across the foramen ovale.
Why the Panel rejects air embolism here
- The timing is wrong. Air embolism is sudden and catastrophic. It does not present over four hours of gradual deterioration — and the infant would not then recover quickly, as Baby M did.
- The skin signs are not diagnostic. On the Panel’s account, patchy skin discolorations are caused by dilation and contraction of small blood vessels in the skin in response to hypoxia. They occur in many conditions and are not diagnostic of air embolism. Non-specific localised patchy skin discolorations have not been reported in infants with venous air embolism, including from intravenous air injection; only Lee’s sign and Liebermeister’s sign are diagnostic (the Panel cites Zhou Q, Lee SK, Am J Perinatol, 27 December 2024).
- The mechanism does not work in practice. If air were deliberately infused through a central venous line, the line would have to be re-infused with fluid to prevent detection. But collapse from air embolism occurs instantaneously. The Panel doubts this could be achieved quickly enough, before other staff on the unit responded to the collapse.
The resuscitation
The Panel describes the resuscitation as chaotic: two doses of adrenaline were given before the airway was secured. Its formal conclusion is that the resuscitation was suboptimal. That is a finding about the unit, not about the nurse on shift, and it is the kind of finding that a prosecution narrative built on “inexplicable collapse” has no room for.
The Panel’s conclusions on Baby M
- Baby 13’s desaturation and bradycardia was caused by apnoea from sepsis or the Eustachian valve.
- The resuscitation was suboptimal.
- There was no evidence of air embolism.
Source: International Expert Panel — Summary Report (February 2025), “Baby 13”. Read the Panel report (PDF). For how to read it, see how to read the Panel report.
Why this specific case matters
Baby M is a conviction-carrying count, and it is one where the Panel identifies a documented, four-hour clinical deterioration in the notes before the event the Crown called sudden and unexplained. The nurse and the registrar both recorded their concern and acted on it. A collapse that is preceded by four hours of recorded deterioration is not the clinical picture of air embolism as the Panel describes it, and the recovery that followed is not either.
The Panel’s report has not been tested in court, and no court has ruled on it. It forms part of the post-conviction material now before the CCRC. Lucy Letby’s convictions currently stand.
What the Panel’s report adds
The Panel reported in February 2025, after the 2023 convictions. None of the following was before the jury in this form:
- The Panel’s conclusion that the collapse was apnoea from sepsis, abdominal distension with ileus and prematurity — or from the Eustachian valve found on his own echo.
- The point that air embolism is instantaneous and catastrophic, and does not follow four hours of gradual deterioration or permit a quick recovery.
- The Panel’s position that patchy skin discolorations are a response to hypoxia in many conditions, are not diagnostic of air embolism, and have not been reported in infants with venous air embolism.
- The practical objection that a deliberately air-infused central line would have to be re-infused with fluid to hide it — while the collapse it caused would be instantaneous.
- The Panel’s finding that the resuscitation was suboptimal.