Sullivan, 27, will return to Australia by the end of this week. There she will receive psychiatric and psychological treatment. Dr Anthony Cairns, a forensic psychiatrist, told the Old Bailey yesterday that he thought she was suffering from a psychotic disorder, mental impairment and was on the edge of being retarded.
In court, Mr Justice Mitchell said that he would normally have imposed an immediate prison sentence, but he believed Sullivan had no insight into her problems.
Sentencing her to 18 months' imprisonment, suspended for two years, he said: "Nothing can put the clock back or restore that baby to her mother and father, or end the pain of the parents or their anguish. I can only hope - having braved the ordeal of these proceedings - that they will understand why I have decided to allow her to return to Australia."
Whether Marcel and Muriel Jongen - whose six-month-old child, Caroline, was shaken to death by Sullivan - understood the judge's decision was not clear. The couple, who have declined to comment throughout the proceedings, again left the court without speaking.
Mr and Mrs Jongen glanced briefly at Sullivan as they walked out of the courtroom.
But later Detective Chief Inspector Phil Wheeler, head of a Metropolitan Police child protection unit and second-in-command of the investigation, said he had spent some moments with the couple after the sentencing. "I will never forget Mr Jongen saying they did not want to ruin Louise Sullivan's life," he said. "But they were very, very upset."
Sullivan had previously pleaded guilty to involuntary manslaughter, having admitted shaking Caroline to death in April 1998 while working as a nanny for the Jongen's at their north London home.
She believed the baby had suffered a fit while feeding and used the outdated "shake and shout" method she had been taught in Australia to try to revive the child. The court accepted that her actions, in which she shook the child for between five to ten seconds - were in no way the result of anger or aggression.
However, it emerged that Sullivan, whose parents split up when she was eight years old, has suffered since birth from a thyroid deficiency.
This has given her an IQ at the lower end of the low/ average band and, crucially, left her inflexible in dealing with new situations.
At one point she told a forensic psychologist who interviewed her that if she was to have a baby she "would need different training".
Mr Justice Mitchell told Sullivan she was "wholly unsuitable for the career you chose and the work you were employed to do.
"Someone of your age, with even only a measure of the training that you received, should and ordinarily would have known better than to expose the baby to the terrible risk, which by your action, you exposed her to."
Explaining his decision to allow her to return to Sydney, he said he was satisfied that Sullivan urgently needed treatment for her fragile mental state. Previously the court was told that Sullivan was at high risk of suffering a nervous breakdown and that if she was sent to prison she would be very vulnerable to self harm.
Sullivan smiled in relief after the judge had finished sentencing and lent from the dock to hug her mother and barrister. Before she left court she was seen speaking to someone on a mobile phone but she declined to speak to reporters.
Her solicitor, Karen Todner, said yesterday that Sullivan's intentions had always been to do her best for a "child which she adored.
"This tragedy has caused enormous distress to all concerned. Louise Sullivan bitterly regrets that her actions led to Caroline's death," she said. "She is very distraught. She is very relieved. It has been very, very stressful."
She said Sullivan would be returning to Australia by the weekend. The family had not yet bought airline tickets and Sullivan had yet to have her passport returned by the police.Reuse content