Katherine Kropas, the newly surprise mother, started her day off Tuesday with intense back pain, but at first, doctors couldn't find anything wrong with her. Then, they did an ultrasound.
"They took one look, and they rushed me off into labor," she told ABC’s Boston station WCVB . "I found out that I was having a baby at 10:15. She was born at 11:06 p.m."
She gave birth to a baby girl, Ellie, who weighed 10 pounds and 2 ounces. Kropas told WCVB she felt that she'd put on some weight, but figured maybe it was just typical holiday weight gained.
Ellie's grandmother, Karen Kropas, told WCVB she's heard of this happening, but never thought she would see it firsthand.
"You laugh and you say that's ridiculous," she told the station. "And then it happens to you, and you're like, 'This really does happen.'"
However research show that one in 475 women do not realize they are pregnant until about 20 weeks gestation and one in 2,455 don’t realize it until they are in labor.
Dr. Jennifer Ashton, a senior medical doctor said she has seen cases like Kropas's in her career.
"It tends to happen in women who are overweight or obese to start, may have irregular periods and are less aware of their bodies," Ashton said. "For most women who have been pregnant, they are aware of multiple physical signs and symptoms, and those signs and symptoms are not subtle."
She said though this case is incredible, it's far from desirable.
"It represents a missed opportunity for parental care for the baby which is definitely not ideal," she said.