When your baby is first born, their stomach is only the size of a marble, stretching out over the first few weeks of their life. This means that they should be fed little and often - around every two or three hours. If you're bottle-feeding your newborn baby, you should only give them 0.5 ounces of breast milk during each feeding for the first few days of their life, gradually increasing the amount as their stomach capacity (and hunger) grows.