Iran's Forensic Organization on Friday said 22-year-old Mahsa Amini's death was "not caused by blows to the head and vital organs and limbs of the body."
Amini died on September 16, three days after she fell into a coma after her arrest in Tehran for allegedly breaching Iran's strict dress code for women.
What do we know about Amini's death?
The lawyer for Amini's family has said "respectable doctors" believe she was hit in custody after being arrested by "morality police."
They also say they were told by other detainees that she was severely beaten and added that they were not allowed to see her body.
Police had previously claimed Amini suffered a heart attack after being taken to a police station to be "educated."
The official coroner's report said did not say whether Amini had suffered from any injuries, but it did refer to her having collapsed in custody.
It said she had regained consciousness before falling again due to what it described as underlying diseases.
The report claimed Amini had suffered oxygen depletion and brain damage.
"She died due to multiple organ failure caused by cerebral hypoxia," the coroner's report said.
The Forensic Organization said the death was related to "surgery for a brain tumor at the age of eight."
Death sparks wave of protests
Amini's death has sparked the biggest wave of protests in Iran for almost three years. Demonstrators have damaged government properties and called the downfall of Iran's Supreme Leader Ayatollah Ali Khamenei.
Rights groups say more than 150 people have been killed in a crackdown by security forces, with hundreds injured and thousands arrested.
In solidarity with the protests, Belgian Foreign Minister Hadja Lahbib and two other lawmakers on Friday cut their hair in parliament in Brussels.
Lahbib, who was born in Belgium to Algerian parents, told lawmakers that the Belgian government would ask the European Union to impose sanctions against the architects of the crackdown.
rc/sms (AFP, dpa, Reuters, AP)