Across Canada, a serious birth defect is occurring with increasing frequency -- and experts don’t know why. Newborns with the congenital condition, known as gastroschisis, are born with their intestines protruding from a hole in their abdominal wall. Other vital organs, like the stomach and liver, can also be found outside the body at birth.

“Every day, we were scared to lose him -- no question with that,” Andrea Cunningham of Moncton, N.B. says of her three-year-old son Dylan.

Dylan, who was born with gastroschisis, wears a scar on his stomach: a sign of the 24 surgeries the toddler had to endure to place his bowels back inside his tiny body.

“Every day, it was the question: was this going to be the day? And, would he make it through?

Perhaps more shocking than the rare condition itself was Cunningham’s discovery that four other babies on her street were also born with gastroschisis.

“It really just makes you question everything about your life,” Cunningham says. ”What you are eating, what you are drinking, the air you are breathing.”

According to the Public Health Agency of Canada, the mortality rate for gastroschisis is approximately five per cent. While most babies survive, full recovery requires immediate surgery after birth and then months, if not years, of treatment and follow-ups.

In Canada, gastroschisis cases have doubled over the past two decades. Other countries are also reporting rising rates. About 150 babies are born with the condition in Canada each year.

“We don’t know why that is,” says Dr. Erik Skarsgard, surgeon in chief at the British Columbia Children’s hospital.

When doctors at the hospital began investigating gastroschisis, they found concentrated pockets of cases on the east and west coasts of Canada, as well as in the far north. Their study is available online.

“What we are seeing is a phenomenon of clustering of cases,” Skarsgard says. “In some cases, there are small areas; communities are having pregnancies with gastroschisis at a much higher rate than other parts of Canada.”

The defect occurs more often in babies born to mothers under the age of 20. Maternal undernutrition has also been established as a risk factor, and so has alcohol and smoking. But while these are factors, they still don’t explain the bizarre geographical concentration of cases, says Skarsgard.

“Is it related to the water supply? Is it another environmental toxin agent? Something in the air? We really don't know and at this point, all we can do is speculate," Skarsgard says.

According to Skarsgard, more research is needed.

Many parents with children who have the condition agree.

Natalya Beatty lives in Moncton. Her two-year-old daughter Rylee was also born with the condition.

“At the end of the day, I just want an answer,” she says. “Why my child ? Why these other mothers? Why did this happen?”

Both Rylee and Dylan may need more treatment as they grow and both their mothers say they won’t have more children until this painful mystery is solved.

“We have a four-year-old,” Cunningham says. “She was fine. But there is too much of a risk with what Dylan has gone through and I don't think it is fair to put anyone else through that knowing it could happen.”

With a file from CTV National News’ Avis Favaro.