Lily Partridge, 22, complained of a headache after the clash at a training session in North Tawton, Devon, in December 2015.
Miss Partridge, a zookeeper, died a day later. An inquest recorded her death was the result of an accident.
She died from "an acute bleed" as a result of a trauma and suffered a cardiac arrest, the inquest heard.
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Front row forward Miss Partridge, who was a founder member of the Exonian Ladies team based at Topsham RFC, collapsed at the side of the pitch.
Team captain Katie Lunnon said she saw Miss Partridge walk off the pitch and complain of a headache - but nobody saw the clash with an opponent.
She said: "I didn't really think anything of it as it was very cold and we were soaked through.
"Lily was kneeling down for a bit and then she said she felt sick and was leaning forward on all fours."
She said the player then collapsed, and was given CPR when she stopped breathing.
The senior university lecturer added Miss Partridge had suffered two concussions earlier that year, for which she had sought medical attention.
Coroner John Tomalin praised Miss Partridge's parents Jeff and Liz for their "brave decision" over her organ donation "at a time when they were trying to cope with the impending death of their daughter".
Her parents said they wanted to see rugby players at all levels receive proper treatment for head injuries, including brain scans.
However, an expert who gave evidence at her inquest said two previous concussions Miss Partridge had suffered while playing had not contributed to her death.
In a statement, her parents said: "Lily loved playing rugby and her dream was to represent Devon. She was the victim of a tragic accident."
They added she had seen her GP after the previous concussions and followed RFU protocols in not playing for a time afterwards.
They added: "A brain scan may have spotted any weakness caused by those head injuries.
"If we had known that her life may be in danger by playing rugby again, obviously she would have stopped immediately.
"It is a great game involving big, strong, heavy, fit athletes but we need to make it as safe as possible.
"There are many thousands of girls and women playing rugby and Lily, like us, wants that to continue."
Consultant radiologist Dr Michael Thomas told the hearing Miss Partridge's two previous rugby concussions were not connected to her death.
He said a CT scan carried out after her collapse showed the blood clot and a bleed went on to happen "within hours of the scan".
A rugby player collapsed with a head injury minutes after an opponent's knee hit her head, an inquest heard.