Last week your neighbors told you that their 18 month old son has been sleeping through the night for the past 2 months. they were happy about this development and were looking forward to many more months of a good night's sleep. this week, however, they say their son has been waking up at night and has been pretty fussy during the day. what is the likely reason for this waking up and fussing?

He might be suffering from  Baby or also known as infantile colic.

Explanation: Infantile Colic or baby Colic is defined as episodes of crying for more than three hours a day, for more than three days a week, for three weeks in an otherwise healthy child. The main cause of Colic is often an allergy to milk protein in powdered formula, But colic can also be a reaction to specific foods in the mother's diet. This can sometimes cause stomach pain.