First weeks: Colic may affect as many as a third of all babies and tends to starts when a baby is three weeks old.
Two months: The worst of the crying -- the longest, the loudest -- occurs at this point.
Three months: Most cases of colic will have subsided significantly by three months.
Four months: This moment is a bit magical for colicky babies and their long-suffering parents. By now, your baby has developed more internal organization; his digestive system is more mature, and food sensitivities may have been solved. He can see clearly and is distracted from his fussing by the visual attractions around him and can play with his hands and engage in self-soothing finger sucking as well as waving his limbs in order to blow off steam.
Six months: Most babies tend to outgrow the medical issues behind colic, like GERD, between 6 and 9 months.
Twelve to Eighteen months: Some cases of GERD can last this long, but the episodes of colic that may accompany it will be long gone.