A CANADIAN whose brain dead pregnant wife is being kept on life support until the birth of their baby has raised almost $US80,000 ($91,000) through the kindness of strangers.

In an online blog, Dylan Benson has been recording his feelings as he grieves for his wife Robyn, whom he called "his rock," while preparing to be a single father to a son.

The mother-to-be suffered a brain haemorrhage at the end of December, when she was 22 weeks along.

She had thrown up and then experienced a piercing headache. She asked Mr Benson to go to the pharmacist for her and when he returned she was unconscious but breathing.

After she was taken to the hospital doctors found out that she had suffered a massive brain leak in the centre of her brain and became brain dead.

Doctors hope to keep her alive until she reaches 34 weeks at the end of March, at which point they plan to perform a Cesarean section.

She is expected to be taken off life support shortly thereafter.

"On one hand, I can't wait to meet my son and try to give him the best life possible and try my hardest to be a great dad for him,'' the 32-year-old wrote on misterbenson.com.

But "on the other hand I know that the day or the day after he is born will be the day that I have to say goodbye to Robyn.''

"I miss her so much.''

The baby now has an 80 per cent chance of surviving.

Mr Benson set up a YouCaring page to try and raise $US36,000 as he has been unable to work.

"The majority of my current and upcoming leave from work will leave me only earning 55 per cent of my salary. I am about to become a single father. Paternity leave for men will only provide me with 35 weeks off from work, and it's likely that I will be spending the first 6-8 of those in the hospital with Iver before I can take him home," he wrote. "I will need funds towards bills, baby supplies, daycare, housing, food, and transportation."

His $US36,000 target has been reached twice over through the generosity of people who have heard his story and reached into their pockets.

Mr Benson also recounts visiting his wife in hospital every day, taking a tour of the neonatal intensive care unit and the kindness of strangers - including a cab driver who dropped off lasagna after being moved by his story.

"It is very difficult to know that our son will grow up never meeting his wonderful mother, and that we will have to say our goodbyes to Robyn within hours of seeing Iver for the first time," he said.

A spokeswoman at Victoria General Hospital in western Canada confirmed Robyn Benson is a patient but could not provide details due to privacy laws.

"Having a soon-to-be-mother on life support and brain dead is a rare tragedy,'' she said.

Last month, a brain dead, pregnant woman was taken off life support at a hospital in the US state of Texas, ending a legal battle that had kept her on a ventilator against her family's wishes.