Weight gain: Normal newborns may lose up to 7% of birth weight in the first few days. After mom's milk comes in, the average breastfed baby gains 6 oz/week (170 g/week). Take baby for a weight check at the end of the first week or beginning of the second week. Consult with baby's doctor and your lactation consultant if baby is not gaining as expected.
Dirty diapers: In the early days, baby typically has one dirty diaper for each day of life (1 on day one, 2 on day two...). After day 4, stools should be yellow and baby should have at least 3-4 stools daily that are the size of a US quarter (2.5 cm) or larger. Some babies stool every time they nurse, or even more often--this is normal, too. The normal stool of a breastfed baby is loose (soft to runny) and may be seedy or curdy.
Wet diapers: In the early days, baby typically has one wet diaper for each day of life (1 on day one, 2 on day two...). Once mom's milk comes in, expect 5-6+ wet diapers every 24 hours. To feel what a sufficiently wet diaper is like, pour 3 tablespoons (45 mL) of water into a clean diaper. A piece of tissue in a disposable diaper will help you determine if the diaper is wet.