Though not likely, it could be pyloric stenosis in newborns, which usually begins between 2 weeks and 2 months of age. One issue with projectile vomitiong is not a reason for alarm, but if it continues, this is a real possiblilty. The muscles around the lower part of the stomach become enlarge and prevent the passage of food. My husband had it for almost 2 weeks before diagnosis and by that time, he was on the brink of death. Don't worry, if it is pyloric stenosis, you will know it. Your baby will projectile vomit every meal. You can have your baby treated (with surgery) before there is any major health problems.
I hope this was a one time thing!
Jen