A Canadian couple is raising the alarm about a rare but serious pregnancy complication, insisting that better screening could have prevented the death of their baby daughter.

Amanda Krznaric had a normal pregnancy. The blood tests and the ultrasound images all showed a normal healthy baby girl. But when Amanda went into labour one night last July, it all went wrong.

"I turned the light on and saw blood. I knew it wasn't normal," her husband Mike Krznaric told CTV News.

By the time they arrived at hospital, their baby, whom they had named Katarina, had bled to death in the uterus.

Doctors told the Krznarics that their baby died because of vasa previa, a rare condition in which blood vessels that feed the umbilical cord actually grow out of the cord and cross the entrance to the birth canal. When labour begins, the vessels rupture, causing fast and usually fatal bleeding.

Though no one knows exactly what causes vasa previa, there are known risk factors such as a low-lying placenta, multiple pregnancies, and pregnancies resulting from in vitro fertilization.

The infant mortality rate from undetected vasa previa is high, from 50 to 90 per cent.

The Krznarics had never heard about the possible complication. They learned about it the hard way.

"It's tragic losing a baby," says Amanda. "You go through nine months and then it's taken away from you."

Dr. John Kingdom says scanning for this problem isn't routinely done in Canada. Ultrasound technicians do look for placenta previa, a similar condition in which the placenta implants next to or covering the cervix instead of near the top of the uterus.

But testing for vasa previa is not routinely done, even though it could be easily added to existing ultrasound scans. If there were a problem, the baby can be delivered by C-section.

Dr. John Kingdom of Toronto's Mount Sinai Hospital says the test is simple and fast.

"How long does it take? Two seconds. That's the message," he says.

"We don't need new equipment or training. Any sonographer knows it's easy to do. It just requires a change in practice guidelines."

The Society of Obstetricians and Gynecologists has issued a statement saying it's looking into whether to set guidelines adding testing for vasa previa to routine ultrasounds.

But their investigation could take a year. And Amanda and Mike are impatient. They estimate 100 babies a year in Canada are at risk of this problem and they've met other parents whose babies died.

"That's why they're making their tragedy public. Until the test is routine, they want expectant parents to consider asking for the scan that could have saved their baby's life.

"There is a problem here. Babies are dying. Our daughter is dead because no guidelines are there," says Mike.