Lucy Letby trial: Astonishing level of insulin found in baby, jury told

Lucy Letby is accused of murdering seven babies and trying to kill 10 others

An "astonishing" level of insulin found in a baby could "only" have come from an external source, a medical expert has told nurse Lucy Letby's murder trial.

Ms Letby is said to have tried to murder the premature twin by giving him insulin on the Countess of Chester Hospital's neonatal unit.

She is charged with murdering seven babies and attempting to murder 10 others between 2015 and 2016.

The 32-year-old denies 22 charges.

She is said to have struck after midnight on a night shift on 4 August 2015 as the baby, referred to as Child F, received a new feed of nutrients via a bag connected to an intravenous line.

Shortly afterwards his heart rate surged and his blood sugars plummeted, jurors at Manchester Crown Court have been told.

Blood samples taken from Child F returned an "extremely high" insulin level of 4,657 and a very low C-peptide level of less than 169, indicating synthetic insulin was in his system.

Expert Dr Dewi Evans, who was asked to review the case by Cheshire Police, said there was "only one explanation" for the "astonishing" blood readings.

"These were very, very striking results. There's only one explanation for this. [Child F] had received insulin from some outside source," he said.

Lucy Letby denies all the charges against her

Dr Evans said he had concluded the drug had most likely been added to the baby's nutrient bag, which is used to intravenously provide feeds to infants.

He explained insulin was a "very dangerous drug" that could cause a sharp drop in glucose levels.

If left untreated, that could "lead to seizures, coma or death", he told the jury.

Dr Sandie Bohin, who reviewed Dr Evans' findings, was asked whether she agreed that "this was a case of insulin poisoning via [feed bag]".

"Yes," she told the court.

The court has previously heard that Child F's glucose levels remained low on the day shift of 5 August even after a a second intravenous line and nutrient bag had been fitted.

They rose to safe levels later that evening after the nutrients were stopped and extra sugar was given independently.

He went on to make a full recovery and was later discharged.

The court earlier heard from three of Ms Letby's former nursing colleagues, who were on shift in August 2015 when Child F fell ill.

They were asked in succession whether they had ever added anything to a feed bag.

Each nurse told the court that they had not added anything, and said insulin would "never" be added to such a bag.

A court order bans the reporting of the identities of the children allegedly attacked by Ms Letby, while identifying parents and some witnesses is also banned.

The trial continues.