Jennifer Scollin, of Seymour, says she thought she had a stomach bug on Saturday.
The pain got worse, so she told her boyfriend, Matt Dillman, to call 911.
But before the ambulance arrived, Jennifer's water broke, marking the first time she realized she was pregnant with her second child.
"It was nothing comparable to how I was with [the first]," she said. "You know? I could see the waves when I was pregnant with her. I could see my belly moving and her fists and her foot. This time I didn't event think I had an enormous belly. Obviously I didn't."
Paramedics delivered a 9-pound, 3-ounce baby boy inside an ambulance in the couple's driveway. Both mother and son were discharged from a hospital Monday and are doing fine.
The couple named the boy Cole Michael Thomas Dillman, who joins his 4-year-old sister, Kelsey.