At what age does reflux peak in babies and when does it resolve?

4, 18 months. Gastroesophageal reflux peaks at about 4 months and resolves by 12- 18 months.
2-4 months. Reflux and spitting up peaks for most babies in the second month of life (contrary to the popular notion that babies spit up a lot when they are first born). More than 50% of 2-month olds spit up, versus less than 10% of 12-month olds. As you can see, reflux gradually improves for most babies over the first year of life.
4 & 24 months. Ger (gastroesophageal reflux) peaks at 4 months of age, decreases after 4-6months, and resolves by 24 months in 98% of the cases.