How do I know if my baby has reflux?

I know babies spit up a lot, but mine does it all the time. How do I know if it’s reflux? 

You are in good company—my four boys all spit up constantly, even until they were one! And my shoulder still has evidence of this, courtesy of my youngest, who is five months old. Spitting up is a sign of gastroesophageal reflux (GER), which is simply when milk or food backs up from a baby’s stomach, typically because the muscles between the esophagus and stomach aren’t yet mature. It’s common and benign, and it will resolve on its own as the sphincter at the base of the esophagus that holds the milk in the stomach gets stronger. It usually improves by four to six months, but even if it takes longer to resolve, it’s not a problem unless it seems to be increasing or is making the baby uncomfortable.

Gastroesophageal reflux disease (GERD), on the other hand, is spitting up that’s painful because stomach acid comes up with the milk. This acidity hitting the esophagus causes pain or heartburn. Your baby might be in pain if he is crying or arching his back—especially after a feed—or is refusing to feed. If you notice these signs, or if your baby is not gaining enough weight or is spitting up blood, see your doctor. Gastroesophageal reflux disease can be treated with prescription medicine, like lansoprazole, which reduces stomach acid. (Editor's note: Some ranitidine formulations were recalled in 2019.) Typically, a doctor will prescribe a drug for a two-week trial period.

Read more: What causes gas in babies and what you can do to help  How to burp a baby