Carrie Fisher's death certificate has been issued but without a cause of death as it's unclear what killed the Star Wars icon.
TMZ reported that the LA County Coroner's Office performed an autopsy on Friday but it has "deferred" reaching a conclusion on the cause of death.
Coroner officials told the celebrity publication that they need to carry out further tests to determine what ended the 60-year-old actress's life.
An official said the cause of death is "not obvious."
As the family are unable to bury Fisher without a death certificate the Coroner's Office issued one now while waiting for more tests - a routine practice.
Fisher died on December 27 after reportedly suffering a massive heart attack on a flight from London days before.
The LA Times reported Reynolds complained of breathing problems to paramedics who attended to her.
The newspaper said a woman in a "fair to serious condition" was taken to Cedars Sinai Medical Centre. She never recovered after being taking to hospital.
MUM, DAUGHTER TO HAVE JOINT FUNERAL
Fisher and her mother Debbie Reynolds, who died just days after the death of her daughter, will have a have a joint funeral, Reynolds' son Todd Fisher has reportedly told ABC News.
ABC reported Fisher said there is currently no date and no confirmed location for the mother-daughter funeral, but plans are in progress.
After his mother's death, Fisher spoke to Good Morning America, recalling how Reynolds "said she missed her daughter and wanted to see her again".
"I don't think she meant it quite like that, but in 30 minutes she went to go see her again," he said.
"She literally spent her life caring after Carrie," he added. "I don't think she hardly knows what to do without having Carrie to look after. I think she wanted to be with her. I'm not joking when I say she left to be with her, and I'm happy about that. That's the only thing I'm happy about."
TMZ reports family members have discussed a dual service as part of their funeral plans for the two entertainment icons.
There is talk of a small, private ceremony and then later a bigger memorial service.
Todd Fisher and other relatives attended the Hollywood Forever Cemetery, a famous resting place for celebrities, to plan the funeral.
Reynolds was at her son's home when she fell ill and died of a suspected stroke.