Anne Shortall could not have survived having her head bound in duct tape if she had still been alive after being beaten with a hammer, the Central Criminal Court was heard.
State Pathologist Professor Marie Cassidy said she could not establish whether the mother-of-three survived the "multiplicity of blows" to her head, but the taping over of her whole face "excluded all possibility of surviving the head injuries".
Prof Cassidy also said the head injuries alone could have caused death, which was "probably fairly rapid" after Ms Shortall was injured.
She said there were nine blows and found the cause of death was blunt-force trauma to the head and obstruction of the airways.
Prof Cassidy was giving evidence for the prosecution in the trial of Roy Webster, who denies murdering Ms Shortall.
Previously, the jury heard he told gardaí in interview that he wrapped Ms Shortall's head and wrists in duct tape after hitting her "three or four times" with a claw hammer.
Mr Webster (40), a father of two from Ashbree, Ashford, Co Wicklow, denies murdering Ms Shortall (47) on April 3, 2015, at The Murrough, also in Wicklow.
He pleaded guilty to manslaughter but that plea was not accepted by the prosecution.
Prof Cassidy said a post-mortem examination was carried out on Ms Shortall's body at Loughlinstown Hospital on April 8, 2015.
Ms Shortall's head was wrapped with silver coloured tape from chin to forehead, concealing the face and obstructing the nose and mouth. The tape around the wrists also covered the sleeves of her jacket.
Ms Shortall had sustained nine blows to the head with a moderately heavy object with a small striking surface, Prof Cassidy said. This resulted in lacerations to the scalp and face, including injuries to her left ear, which was split.
There were five lacerations to the top of the head, another along the right ear, extensive trauma to her left ear, a laceration at the outer end of her left eyebrow and the last along her chin.
There were also bruises and abrasions to the hands that Prof Cassidy said could have been "defensive-type" injuries.
The skull was uninjured and had not been fractured.
There was slight swelling to the brain but no evidence of direct brain injury and she was otherwise healthy. There was no evidence of a pregnancy.
"The multiplicity of forceful blows to the head could have caused rapid concussion or unconsciousness," Prof Cassidy said.
She told the jury this could cause death but was also "compatible with continued life".
There was "no evidence of a sustained attempt at strangulation".
It was not possible to determine if the tape was applied when Ms Shortall was still alive, she said. "It can't be excluded that death was due to head injuries alone."
"If they were applied while she was still alive this would have excluded all possibility of surviving the head injury," she said of the head bindings.
"The cause of death was blunt-force trauma to the head and obstruction of the airways," Prof Cassidy concluded.
Cross-examined by Brendan Grehan SC, for the defence, she said a claw hammer produced as an exhibit was consistent with the injuries.
The jury also heard Ms Shortall knew she was not pregnant when she went to her GP three weeks after she had sex with Mr Webster.
The doctor, Geraldine O'Kelly, said Ms Shortall was referred on for a procedure that could not have been performed if she had been pregnant.
The court had already heard Mr Webster said Ms Shortall blackmailed him by threatening to "reveal all" about a one-night stand they had. He said she claimed she was pregnant and asked him to pay £6,500 (€7,445) for an abortion.
The trial continues.