Legendary comedian Joan Rivers died on September 4 at the age of 81.

Joan Rivers' final cause of death has been revealed over a month after the fashion critic passed away.

The New York City Medical Examiner's Office has reportedly found that the actress died from complications due to surgery, according to The Hollywood Reporter.

"OCME [Office of the Chief Medical Examiner] has completed its investigation. The cause of Ms. Rivers' death is anoxic encephalopathy due to hypoxic arrest during laryngoscopy and upper gastrointestinal endoscopy with propofol sedation for evaluation of voice changes and gastroesophageal reflux disease. The manner of death is therapeutic complication," spokeswoman Julie Bolcer said in a statement.

Bolcer added, "The classification of a death as a therapeutic complication means that the death resulted from a predictable complication of medical therapy."

The State Department of Health reportedly launched an investigation into Yorkville Endoscopy following Joan Rivers' death, which occurred several days after the talk show host went into cardiac arrest at the New York City clinic, according to Fox News. She was soon rushed to Mount Sinai Hospital where she was reportedly put on life support.

The clinic reportedly parted ways with its medical director, Dr. Lawrence Cohen, soon after Joan Rivers' death.

"We continue to be saddened by our tragic loss and grateful for the enormous outpouring of love and support from around the world. We have no further comment at this time," the author's daughter Melissa Rivers said in a statement to THR.