Tania Clarence, 42, had pleaded guilty to the manslaughter of Olivia, four, and three-year-old twins Ben and Max by diminished responsibility.
Wonâ??t face a murder trial
At a hearing at the Old Bailey in London, Judge Sweeney accepted her plea so she will no longer face a murder trial in the New Year.
“It is clear on the evidence Mrs Clarence killed her three children because she wanted to end their suffering and at the time she committed the act she could not see any alternative or any other way out of their joint suffering,” said prosecutor Zoe Johnson QC.
Clarence, who was not in court, will be sentenced on November 14 when she is likely to face a hospital order.
After killing the children she tried to commit suicide.