The new born baby's stomach & how much can baby's tummy hold.

1-day old baby: 

A newborn has a tiny stomach the size of cherry that can only hold a teaspoon of colostrum (your first milk before the milk production really kicks in). Because your baby's stomach is so tiny, you'll need to feed her constantly in the first 24 hours. She needs eight to twelve feedings during the first 24 hours. This is because her stomach is so small, just the size of a cherry, and gets full and empties very quickly. 

3 days old baby: 

The stomach of 3 days old baby is already 4 times larger. Feed your baby on demand and monitor the number of wet diapers. If you see no wet diapers for 24 hours, you want to connect with your doctor or nurse.

7 days old baby:

The stomach is the size of an apricot and can hold 1.5 to 2 ounces of milk. Mature breastmilk consists of 90 per cent water and 10 per cent of carbohydrates, proteins and fats necessary for both growth and energy.