Acid reflux in infants is an extremely common condition. It happens when contents from the stomach back up into the esophagus, perhaps because a valve in the stomach does not have an effective seal. The stuff of an infant's stomach is often acidic, and it burns. So it is like infant heartburn. We treat the acid reflux, and it helps with the colic - sometimes - because acid reflux does not always cause colic.
Adults frequently project their own experience onto their infants, but infants' stomachs are very different from those of adults. The acidity of an immature stomach is not nearly comparable to that of an adult's. Researches have confirmed that many infants have some reflux but that is does not bother them. Consequently, most infants do not experience discomfort when they have acid reflux.
Of course, there are some exceptions. Some infants do experience pain when they reflux. In fact, these issues are not necessarily accompanied by vomiting. When the food comes up, the infants simply tense up their bodies and grimaces. Excessive crying can certainly occur with acid reflux, and this condition is sometimes misdiagnosed as colic.
We do not know why colic is related to some infants but not others. What we do know is that having an infant with acid reflux can put a tremendous stress on the family, and that perspective must be addressed as well. It may sometimes be difficult to differentiate between reflux and colic, but there are a few helpful clues. The discomfort usually reaches its highest intensity within an hour after feeding. Thus, infants tend to cluster their crying after mealtime. A baby with true colic is more likely to cry most often when they are about to fall asleep, and the pattern does not correlate with their feeding schedule.
Reflux in babies can be serious. If you suspect your four month old with reflux, get an appointment with your pediatrician. The doctor may prescribe a medication or order additional diagnostic tests to evaluate the reason for crying.