Another age-related "false alarm" is that babies will experience several "growth spurts" in the first few months of life. Generally, these occur around two to three weeks, six weeks and three months of age or they may happen at any time. These are days when baby wants to nurse longer and more frequently to build up mother's milk supply. Follow baby's lead on this by letting him breastfeed as often and as long as he wants. This will help bring up milk supply quickly. The breasts work on the law of supply and demand. The more baby "tells" mother's breasts to make milk, the more milk she will have.