According to the American Academy of Pediatrics (AAP), "Exclusive breastfeeding is ideal nutrition and sufficient to support optimal growth and development for approximately the first 6 months after birth. Infants weaned before 12 months of age should not receive cow's milk feedings but should receive iron-fortified formula."
Exclusive breastfeeding for 6 months is generally agreed to meet infants' nutrient requirements, although there may be risk of deficiency of some micronutrients such as vitamin D and iron. Exclusive breastfeeding means an infant receives only breast milk. This means no water, juice, infant formula, or food. Mixed feeding describes a feeding pattern practiced by many women in the U.S., where the infant receives breast milk, supplemented with baby formula. Several recent surveys have shown mixed feeding to be a prevalent practice in the U.S. This type of feeding may improve intake for particular nutrients that are of special concern for infants 4 to 6 months of age (i.e., iron and vitamin D).
Parents should receive accurate information about all appropriate infant feeding options to help ensure their child's optimal nutrition and overall wellbeing, regardless of whether they choose to breastfeed or formula-feed their infant.
Infants weaned before 12 months of age should not receive cow's milk feedings but should receive iron-fortified formula. -- AAP
For mothers, breast feeding helps with recovery from pregnancy and childbirth and provides certain health advantages. Some studies show that breastfeeding may help reduce the risk of breast cancer and may help with weight loss.