A mother accused of murdering her two-month-old son smiled slightly as she told a social worker she had killed him, a court has heard.
James Hughes died in June 2016 after being taken to hospital from his family home in Shotton, Flintshire.
His mother, Hannah Turtle, 22, has denied murdering the infant.
Mold Crown Court heard how Ms Turtle showed "no real emotion" as she told social worker Fleur O'Hagan how she had suffocated her son.
Ms Turtle has accepted that she stopped her child breathing on three occasions within a ten-day period but claims she did not intend to kill him or cause him serious harm.
She denies murder, three charges of ill-treatment and two of administering poison amid allegations that she gave him her own anti-depressant medication in his milk.
Ms O'Hagan told the court that she and a colleague had seen the defendant before her police interview because of concerns she might harm herself.
Ms Turtle told her she had put her hand over James' mouth while he was sleeping.
She said she had not done it before and had not been able to tell police because there had been too many people there.
The social worker said she wanted to empathise with her, and so suggested that the baby might have been crying but Ms Turtle said no, that he was asleep in his crib.
Ms O'Hagan told the court Ms Turtle said: "I just put my hand over his face for a few seconds and he stopped breathing.
"It was either this or self-harming."
Ms O'Hagan said: "I was very much aware that it needed to be dealt with by the police. I told her I needed to speak to the police."
She went out and a colleague remained with her in the room.
When she returned, she said Ms Turtle's mood had changed.
She said she had heard the voice of a family member in her head - she did not know who - telling her that she was a bad mother and that was why she had done it.
Ms O'Hagan said Ms Turtle was distressed about her partner and his mother finding out what she had done.
She had been talking about something very sad but she was smiling which was unusual, she said.
Asked by prosecutor David Elias QC if she was showing any particular emotion, Ms O'Hagan replied: "No, not in the way that you would expect."
Cross-examined by defence barrister Gordon Cole QC, Ms O'Hagan said the most emotion Ms Turtle showed was when she was arrested.
"She was very tearful then," she said.
Ms O'Hagan's colleague Nigel Blacoe, a community mental health nurse, told the court that after she left the room, the defendant repeated the account of killing James to him.
She told him that she needed help and that she had been hearing voices telling her that she was a bad mother and that she did not deserve James.
The defendant said she just wanted help, that the voices would not stop, and had returned to her after the birth of the baby.
They were saying negative things, calling her a bad mother and that she did not deserve the baby.
She did not want to "get away with it", sounded remorseful for what she said she had done and showed him a locket containing a picture of James, Mr Blacoe said.
The trial continues.