Vomiting in Infancy
All children spit up, but some children spit up more than others. The milk your baby drinks goes down their esophagus and past the gastroesophageal (GE) sphincter, which is supposed to keep the milk in their stomach from coming back up the esophagus and out their mouth. All babies have a loose GE sphincter; it’s a matter of how loose their sphincter is, which will determine how much a baby spits up.
A baby can only hold so much liquid volume in their stomach. A good rule of thumb, they can hold about half of their weight in ounces. For example, a 8 lb baby can hold approximately 4 oz of liquid. If you are breast feeding, although you cannot measure how much milk your baby is taking in, you can alternate feedings on each side of the breast every 1.5 to 2 hours .
A rare case of spitting up is caused by pyloric stenosis, where the muscle on the other side of the stomach (out flow from the stomach to the intestine) is too tight. It causes pressure to build up in the stomach until it explodes out the mouth and may be projectile – shooting several feet. While I see GE reflux weekly, I see pyloric stenosis less than once a year.
Extremely rare cases of vomiting would be a very sick child who is lethargic or has a high fever. Get that baby into the doctor immediately.