These parents knew the telltale signs of pregnancy, but this time Carri said nothing made sense. There were no pregnancy symptoms -- no morning sickness, mood swings or cravings. Her menstrual cycle was always erratic -- so that wasn't a clue either.
And with her first two pregnancies, Carri put on a lot of weight. Pregnant with second child Dylan, she said she gained about 60 pounds. This time, she only put on 10 pounds -- weight she thought she gained because she stopped smoking.
During her other pregnancies, Carrie had consistent prenatal care.
"That was the first thought I had when I delivered him ... 'There's no way this baby's alive.' It scared me," she said. "I thought, you know, we didn't know he was there. How can he be healthy?"
Tim Foster was one of the first paramedics to arrive on the scene that night in April 2009.
"Usually, when mothers deliver babies at home, they're usually premature ...and the outcome's usually never good," he said.
Carri was strapped to a gurney for the 25-mile trip to the hospital. Finally, doctors assuaged their fear and anxiety: Carri's baby boy was healthy -- and big. He weighed in at 9 pounds, 9 ounces.
They named the baby William Gerald Emmons after his late grandfathers.
"Her dad and my dad had passed," said Ryan. "And we had a hard time with it. And we just thought that maybe they're upstairs laughing at us, thinking that, you know, 'We're still up here and we, we're watching you guys.' And, you know, we, we thought that that was a gift from my dad and her dad. So we named them William from her dad and Gerald for mine."
Carri's family was soon told the unimaginable news. Her older sister, Kelli Sabin, thought it was a prank.
"The phone rang... I looked at the clock and I thought, 'Oh, this is not good to get a call from my mom this early in the morning... And she said, 'Your sister gave birth last night.' And I stopped for a second and said, 'To what?'" Sabin recalled.
Sabin had just seen her sister at Easter dinner -- only four days before the birth -- and said she didn't notice any signs that Carri was pregnant.
In fact, over the previous nine months, nobody noticed any signs of pregnancy. Carri said no one had asked her if she was pregnant.
Dr. Ashley Roman, a clinical assistant professor at NYU School of Medicine and a specialist in high-risk pregnancies, said surprise pregnancies aren't so implausible after all.
"There really doesn't seem to be much scientific data on this topic, but I think if you were to poll every obstetrician, we've all seen it at some point in our career," Roman said. "We've seen the woman who comes in at term or near term and who didn't realize she was pregnant, and gives birth."
Roman said there are reasons a woman can carry a baby full-term and miss the signs.
"What's difficult, what many people say is, but how could you miss your growing belly? But some women tend to hide it well, their body just simply disguises it," she said. "They might chalk it up to the fact that they, maybe, they've put on a couple pounds and, 'I've gained weight for one reason or another.' You know, they're getting older, their metabolism has changed. There are a lot of ways to talk yourself out of this."
But Carri and Ryan were not in denial.