how early can colic start
1 Colic is likely to start around age 2 weeks if your infant is full-term (or later if premature). 2  It almost always goes away on its own by 3 or 4 months. 3  Your baby's sex and birth order, and whether you breast- or bottle-feed, donât affect it.  Kids who had colic as babies are no different from those who didnât.