Acid reflux, or gastroesophageal reflux (GER), occurs when the contents of the stomach--including acid--back up into the esophagus. Usually a ring of muscle called the lower esophageal sphincter (LES) keeps food where it's supposed to be, but in infants, it's not fully developed. As a result, reflux is very common in babies, and when her LES opens to let out gas as you burp her, your baby is quite likely to spit up. That's the most common symptom, but there are others.
Regurgitation
Regurgitation in the form of wet burps or wet hiccups, spitting up or vomiting is the most widespread sign of acid reflux among infants. This can occur after a meal or when your baby cries, coughs or strains, and can cause bad breath. If your baby has teeth, stomach acid washing over them can cause the enamel to weaken, which may lead to tooth decay. But usually spitting up is not something to worry about, and some doctors refer to babies who regurgitate often, but are otherwise healthy, as "happy spitters." According to the National Institutes of Health (NIH), "More than half of all babies experience reflux in the first 3 months of life, but most stop spitting up between the ages of 12 to 24 months. Only a small number of infants have severe symptoms."
Feeding Problems
Sometimes the signs of infant reflux are more serious. The NIH reports that "In a small number of babies, GER results in symptoms that cause concern." These symptoms can severely affect your baby's well-being. Some babies with reflux associate eating with pain, so they become fussy at feeding time or refuse to eat. Others will be irritable or cry inconsolably after eating. If your baby acts like this, take him to the doctor and have him weighed regularly, as some fail to thrive or are slow to gain weight. He may even experience blood loss due to stomach acid burning the esophagus.
Sleep Problems
When your baby lies down, especially if it's right after a meal, gravity increases the chance of reflux. This can make it difficult for him to sleep, so you might find him waking up and crying or having problems breathing. In some cases, babies can experience sleep apnea, in which they stop breathing momentarily.
Respiratory Problems
Some asthma-like breathing problems are a result of acid reflux. If your baby chokes, coughs, breathes noisily or wheezes a lot, it could be a result of some of her stomach contents ending up in her lungs or windpipe. In more severe cases, reflux can even lead to bronchitis, pneumonia, sinus infections and ear infections.
