WA mum admits killing her unwanted baby

A West Australian mother who starved her three-month-old daughter then allowed the body to decompose inside a cooler bag in a shed has pleaded guilty to manslaughter mid-way through her murder trial.

Tamara Louise Thompson had been on trial in the WA Supreme Court accused of failing to provide proper nourishment to baby Destiny, whose body was discovered wearing a nappy and wrapped in a muslin cloth inside a cooler bag in July last year.

The trial was abandoned on Wednesday when Thompson pleaded guilty to the lesser charge of manslaughter.

Some members of the jury cried last week as prosecutor Carmel Barbagallo outlined the state's case, while Thompson also wept throughout the proceedings.

Thompson fell pregnant to her meth dealer and Destiny was not planned or wanted, the jury was told.

Destiny was born six weeks premature in Perth, but was healthy and moved to Geraldton with her mother, who had five other children, two of whom lived with her.

Ms Barbagallo said Destiny was last seen alive by someone other than her mother in mid-May 2015.

Thompson lied about where Destiny was after she died, telling some people she was with friends and others that she was in the care of the Department for Child Protection, Ms Barbagallo said.

Thompson will face a sentencing hearing on Friday.