A mum claims the doctor's discovery of her daughter's one-in-a-million diagnosis was "completely accidental".
Ebby Tidswell, 30, was 28-weeks pregnant when she was told her unborn daughter Rosie had Vein of Galen Malformation (VGM).
The rare condition, which occurs during pregnancy, results in abnormal connections between blood vessels within the brain, affecting one in a million children born in the UK each year.
Ebby said it was "completely accidental" that doctors discovered the condition when they did.
She added symptoms varying greatly from child to child and so doctors were unable to tell her what this would mean for Rosie until she was born.
Ebby, from North Wales, told the LiverpoolECHO : "I was measuring big so they sent me for a growth scan just at my local hospital and it was then when it was picked up.
"It was completely accidental that it was picked up.
"I remember one of the first times we went to Liverpool Women's Hospital, they sat us down in the room and they said there was going to be three possible outcomes.
"There was a third of a chance that she would come out and she would be absolutely fine, there was a third of a chance she would come out and she'd have developmental delays or brain damage and quite severe disabilities and there was a third of a chance that she wouldn't survive at all."
Rosie was born at Liverpool Women's Hospital via cesarean.
When she was 12 hours old she was transferred to Alder Hey Children's Hospital for close observation.
Ebby said: "She was born stable and she didn't really seem to have any problems in terms of the Vein of Galen Malformation.
"I think it was on day nine we were told to take her home. We were going to Alder Hey every or so just for scans and things."
When Rosie was 10-weeks-old, she needed to have her first operation after it found that her condition was putting pressure on her heart and she was going into the early stages of heart failure.
The surgery was a success and Rosie has since had another operation when she was six months old.
Rosie is now a "happy, healthy and smart" three-year-old.
Ebby said: "They're absolutely amazed at how well she's doing.
"She doesn't really have any developmental delays, she is meeting all of her milestones.
"She's not poorly in any way, her heart is absolutely fine and they hope the [VGM] could close down on its own because every year that she's been for an MRI it is getting smaller.
"We're just absolutely amazed. I say like a million times a day of how proud we are and how grateful to have somewhere like Alder Hey that have done what they've done for her.
"She's just like any other normal three-year-old that you'd expect.
"She's happy, she's healthy and in terms of the intelligence she has it's absolutely crazy how amazing she is because obviously, we expected developmental delays but she's never had anything hold her back, she just gets on with things."
