Sporadically. Typically babies will experience approximately 5 growth spurts throughout the first year of life. These most commonly occur from 1-3 weeks old; 6-8 weeks old; and then at 3, 6, and 9 months of age. The end result is a tripling of birth weight by age one for most babies. Common signs of growth spurts include increased appetite, waking up hungry, and slightly more fussiness.
1st year of life. Babies grow their fastest in the first year of life. They double their birth weight at 3-4 months and triple their weight at one year. If your baby is not gaining in weight and height, as evidenced on growth charts, your pediatrician could refer to a specialist for possible causes.