Baby's development during the first three months

  • A newborn’s brain, digestive system and the five senses rapidly progress soon after birth.
  • Healthy brain growth and baby development is influenced by nutrition, especially intake of key components such as DHA and Iron.
  • Your baby’s developing digestive system needs only breastmilk or formula, at least until four months.

Your baby is growing rapidly throughout his first years of life. A healthy full-term baby will typically double his birth weight at six months, triple at one year and almost quadruple before he turns three. That’s why keeping track of his height and weight is so important to your baby's growth and development.

Don’t miss an inch

Baby's growing quickly! Check out MyGerber Tools to keep track of lots of things from how your body changes during pregnancy to how much your baby eats as they start to sprout. 
The amazing brain
Remarkably, by the age of two, our brains reach around 80% of their adult size. The first few months his brain will develop lots of complex systems that carry into later in life. Building these pathways rely on the right nutrients and, without them, his brain may not develop to its fullest. Zinc, Iron, iodine, B vitamins, Choline and omega-3 fats, such as DHA, are some of the keys to a healthy developing brain and your baby's growth and development. The first few months, your baby’s brain will obtain these nutrients from breastmilk or infant formula.

Baby’s developing tummy: a work in progress

During the first few months, your baby is producing a limited amount of digestive enzymes. He’s only capable of digesting the proteins found in breastmilk or infant formula. As he grows, his digestive tract is also maturing, which will eventually allow him to eat and successfully digest different foods.


During the first week in your baby's development, small frequent feedings are best. Too much formula or breastmilk and he could spit up! Now is the time to start learning his hunger and fullness cues.

Breastmilk is naturally gentle on your baby’s developing digestive system. Because newborn digestive systems are developing in the first 3 to 4 months, they can be very sensitive to protein sources other than milk from Mom. The protein in breastmilk is usually well digested and tolerated by his developing digestive system.

Your baby is getting all that he needs from breastmilk or infant formula up until about four months, so there’s no need to hurry along the process.
How was the information in this article?
Is my baby at risk for food allergies?
Read More
Your baby's hunger & fullness cues
Read More
Off to a nourishing start
Read More
The road from newborn to infant
Read More
Newborn developmental milestones
Your baby's need for iron
Read More