The digestive system begins to develop in the womb, but significant maturation occurs postnatally. At birth, an infant's digestive system is still immature. The stomach has limited capacity and produces less acid, while enzymes necessary for digestion are not fully active. Over the first few months, these functions gradually improve. For example, the enzyme lactase, which is critical for digesting breast milk, is present in high amounts during infancy and decreases as the child grows.
