Q&A: Is GERD serious and what can I do about it?

It sounds like you've already done the first and most important thing when it comes to babies who seem to throw up after feedings, and that is discuss it with your baby's doctor. The reason I say that is because questions and concerns about babies who spit up and/or vomit are actually very common and it's quite important to make sure that babies are able to continue to eat and gain weight well.

In the case of reflux, the diagnosis itself simply means that the contents of a baby's stomach has the inconvenient tendency to "come back up" instead of moving on through the stomach and down into the intestines. In other words, it refluxes back up out of the stomach into the esophagus—and sometimes all the way up and out the mouth. Sometimes this simply results in an otherwise happy baby who spits up a lot and requires that the upholstered furniture be protected accordingly. While definitely messy, it doesn't interfere with their ability to eat or gain weight. For some babies, however, instead of being "happy spitters," they are irritable, uncomfortable, and/or unable to keep enough down to gain weight. If this happens, then it definitely warrants further evaluation and a discussion of what can/needs to be done about it.

Smaller, more frequent feedings can sometimes help decrease the amount of spitting up (presumably to fill the stomach less, making it less likely for the stomach's contents to come back up), as can more frequent burping and positioning babies so there is less pressure on their stomachs. And in some circumstances, medicine may be prescribed, when necessary, to treat reflux.

Having said all of that, not all spit-up is created equal. In particular, I notice that you made a point of saying that your son "throws up," rather than simply that he "spits up." I've found that describing the difference between spitting up (more passive, with less force) and vomiting (more forceful—even projectile) can be particularly challenging. But it's worth distinguishing between the two because of a particular condition that can affect babies in the first weeks and months of life called pyloric stenosis. This condition involves the muscle at the bottom of the stomach, which gradually becomes too tight and as a result, makes it progressively harder for stomach contents to pass out of the stomach down into the intestines. Instead, they are forced back up—at first in the form of spitting up, but gradually with increasing force that ultimately results in "projectile vomiting." Increasingly forceful spitting up and vomiting is therefore something that all parents should be on the lookout for and discuss with their pediatricians. Unlike reflux, which may not require any medical treatment before noticeably improving over time, pyloric stenosis always gets progressively worse until it is recognized and treated with a simple but necessary surgery.