A mother accused of murdering her newborn daughter suffered an "acute stress reaction" after giving birth, a psychiatrist has told a jury.
Mental healthcare boss Rachel Tunstill, 26, accepts she stabbed Mia Kelly to death with a pair of scissors in the bathroom of her home in Burnley, Lancashire, but says she has no memory of doing so.
She then placed the lifeless body of her daughter into carrier bags and put them in the kitchen bin.
Consultant forensic psychiatrist Dr Fareed Bashir told Preston Crown Court he thought Tunstill's balance of mind was disturbed in the period following the birth of her child and added: "I believed and believe that Rachel Tunstill was suffering an acute stress reaction."
He said the reaction came against a background of mental disorder, including depression and her condition of Asperger's syndrome which she had been diagnosed with as a child 16 years ago.
Dr Bashir, acting for the defence, said he could not establish exactly what was going through Tunstill's mind when she picked up the scissors on the evening of January 14 this year.
But he said: "Giving birth to a child in a bathroom, in a toilet, was extremely stressful.
"Her brain should have told her that 'this is a child and I should care for the child' but because she had Asperger's and other disorders, her emotions would not have fitted with what her brain had told her.
"There would have been a clash of confusion in her mind as to what to do. That may be an explanation."
He said in his opinion Tunstill's Asperger's was "severe" because her emotional disconnect was so apparent.
The court heard the defendant had "a significant" family history of mental illness and had self-harmed from the age of 11. She was diagnosed with Asperger's in 2001 after she had difficulties in socially interacting with her peers.
Giving evidence on Wednesday, Tunstill - who has a degree in psychology and a masters in forensic psychology - said she began to hear voices in the latter part of 2016 and was "terrified" that people were trying to kill her.
Upon examining Tunstill since her arrest, Dr Bashir said his observations were that Tunstill had suffered auditory hallucinations and paranoid persecutive beliefs in the months leading up to her arrest.
He said Tunstill had told him at the time of the birth that "emotionally her head was all over the place", she had been in excruciating pain and was "acting on autopilot".
Tunstill claims she was unaware her pregnancy was virtually full-term and thought she was having a miscarriage at the flat in Wellington Court she shared with her partner, forklift driver Ryan Kelly, 31.
Tunstill, a deputy care manager at a local residential home for people with mental health issues, denies murder.
The trial continues on Thursday.