Amanda Byron, 21, gave birth Thursday to Jonathan Patrick Rozzi after 4 hours of labor and 10 minutes of pushing, the Boston Herald reported.
"When they told me his weight I didn't realize how big a deal this was until everyone started taking pictures," said Byron.
"The nurses were all so surprised at his size. I was told the last big baby was 12 pounds but that was a C-section. Everyone's asking me 'How did you do it?' It wasn't as much pain as I thought it would be. So I just smile and shrug," said Byron.
Byron said she knew, based on ultrasound results, to expect a larger-than-average baby.
"We thought maybe 9 or 10 pounds, and that the average size is 6 to 8 pounds. They don't know why he's so big. I had a normal, well-balanced diet -- avoided caffeine and sodas," Byron said, adding that neither she nor her fiance, Eric Rozzi, come from families with such large people.