About 1 in 5 of all infants suffer from colic, which is spates of crying that go on for hours for no apparent reason. Although distressing for the child and exhausting and emotionally draining for the parents, the condition itself is harmless and usually ends by the time a child is 4 months old - although it can last until 6 months for some babies.
It's a common, yet poorly understood condition. Your baby may appear to be in distress. However, the crying outbursts are not harmful and your baby will continue to feed and gain weight normally.