Burps and spitting up after meals are typical reactions for babies in the first months of their life and are nothing to worry about. This is normal reflux. Indeed regurgitation is the most common symptom and happens at least once a day in a third of infants at 4 months of age. Normally, acid reflux doesn't interfere with a baby's growth or well-being and does not mean that anything is wrong.
However, in some babies acid reflux may be a symptom of more serious conditions, such as gastro- oesophageal reflux disease (GORD). We talk of GORD only if your baby spits large amounts of food, not only immediately after feeding but also anytime during the day, long after meals. Typical signs are:
Gastro-oesophageal reflux disease may be a secondary manifestation of other conditions such as a food allergy or CMA. If a food allergy is suspected, your child’s doctor may suggest an elimination diet substituting a hypoallergenic formula, in order to manage the dietary requirements of infant GORD.
If you suspect GORD in your infant, please consult your child’s doctor immediately.
Hill et al. J Pediatr 200; 136; 641-7
Thomson et al. Pediatr Asthma, Allergy And Immunol 2006; 19(4):205-213