The report stated Murphy's menstrual period contributed to her anemia and left her in a weakened state and vulnerable to infection. It also contributed the effects that a host of drugs, including hydrocodone and acetaminophen, had on the 32-year-old actress, according to the report.
Coroner's officials had already concluded Murphy's death was accidental, but likely preventable. She died after collapsing in her Hollywood Hills home on Dec. 20.
The report notes that the medications found in Murphy's system were consistent with treatment of a cold or respiratory infection. Murphy's mother and husband had reported the actress was ill with flu-like symptoms in the days before her death.
An autopsy found no evidence that Murphy abused drugs. Investigators found numerous prescription medications in the actress' home, which she shared with her mother, Sharon, and husband, Simon Monjack.
The actress was taking anti-seizure medications and hydrocodone, the report said.
Murphy had been complaining of severe abdominal pain for seven to 10 days before her death. The report states her family thought it was a result of her menstrual period, which they told investigators was often severe.
The "Clueless" and "8 Mile" star had a doctor's appointment scheduled, but died before her appointment, Assistant Chief Coroner Ed Winter has said.
Attempts to reach Monjack or Sharon Murphy on Thursday were unsuccessful.
The autopsy report noted Murphy suffered from diabetes and had to go to the hospital for treatment in Oregon in April 2009. The report found her to be otherwise healthy.
Monjack said in an interview in January that he and Murphy were planning a family and contemplating a move to New York before her death. He said his wife had been taking anti-seizure medications after a health episode she experienced while filming "8 Mile."
Her big screen roles diminished after 2005's "Sin City," but Murphy had been juggling several movie projects in the months before her death.
By ANTHONY McCARTNEY