These can happen at any time, but in the early months growth spurts often occur at around: (kidshealth.org)
We are currently in the middle of the 3 month growth spurt so he seems to feeding very frequently and for long periods of time at the minute but I am sure this will only be for the next few days. (naptimenatter.com)
If she hasn't had a 3 month growth spurt yet, then she could be in one. (babywisemom.com)