The type of stroke Cilla Black suffered at her Spanish villa does not normally cause sudden death, the post-mortem examination has reportedly said.
The 72-year-old fell and hit her head at her home on the Costa del Sol at the weekend.
A post-mortem, reported to have been published by Spanish authorities, said a range of factors including the time taken to receive medical attention can affect chances of survival.
High temperatures also contributed to the death of the TV and singing star, the 10-page report said.
According to reports it said: "A subarachnoid haemorrhage by its characteristics doesn't normally cause sudden death, but it can produce a loss of consciousness and depending on the state of health of the person and the context (place and way in which the trauma occurs, time it takes to be medically assisted, position people are found in etc) can cause death in a more or less defined period of time.
"That can either be through lack of consciousness or obstruction of the airways by the tongue or the lack of medical attention during a certain time period, causing a brain alteration with subsequent heart and/or lung consequences and death."
It added: "The most probable diagnosis of the cause of death, at this moment in time, pending lab results that have been requested, is: head injury, subarachnoid haemorrhage, as a result of a fall. Contributing to death, but not in a decisive manner, the high temperature the body remained in after this loss of consciousness."
The star would not have suffered, a statement from her publicist released earlier this week said.
In a joint statement on Tuesday Black's three sons Robert, Ben and Jack said they were "devastated" by their mother's death, but thanked those who have paid tribute to her.
"The tributes and condolences have really helped us through these difficult times."
They added that they hoped to bring their mother back to the UK as quickly as possible.
Stars including Sir Cliff Richard, Sir Paul McCartney and Christopher Biggins have paid tribute to the former Blind Date presenter.
Born Priscilla Maria Veronica White in Liverpool, she became one of the nation's favourite entertainers after transforming herself from a successful singer in the 1960s to the front woman on shows such as Surprise Surprise.