Joan Rivers’ official cause of death has been revealed by the New York City Medical Examiners office.

Joan Rivers' Cause Of Death

New York City Medical Examiner spokesperson Julie Bolcer revealed in a statement on Thursday that Rivers’ death was caused by complications due to surgery.

“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," Bolcer’s statement reads. "The classification of a death as a therapeutic complication means that the death resulted from a predictable complication of medical therapy."

In layman’s terms, during Rivers larngoscopy and endoscopy in which she was sedated with propofol, not enough oxygen was getting to her brain, leading to brain damage. Rivers suffered both cardiac and respiratory arrest. As for the “predictable complication,” it is believed that what happened during Rivers’ surgery was not the result of a medical error, but an understood danger when a patient is sedated.

Melissa Rivers Responds To Findings

Melissa Rivers, Joan Rivers’ surviving daughter, is rumored to be building a case against Yorkville Endoscopy, the medical clinic at which her mother underwent her surgery. "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,” Melissa told ABC News in response to the ME’s statement.

While the New York State Health Department continues its investigation into Rivers' death, Melissa is allegedly planning to file a lawsuit. “It’s very difficult to discuss something so unpleasant with her, but she is going to launch a lawsuit,” the friend told the Daily Mail earlier this month.

It has previously been reported that Rivers had gone to Yorkville to undergo an endoscopy, which was to be performed by gastroenterologist Dr. Lawrence Cohen. She was accompanied to the surgery by ENT to the stars Dr. Gwen Korovin. Some reports allege that Cohen allowed Korovin to perform an unauthorized biopsy or unauthorized laryngoscopies on Rivers, which led to her death.

Following the ill-fated surgery on Aug. 28, Rivers remained on life support until she died on Sept. 4 at age 81.