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Infant Milestones (0-1 Year)

Growth and Development | Physical Development | Cognitive Development | Emotional & Social Development | Language Development | Sensory & Motor Development

Your newborn will grow and change more in the first year of life than during any time, making it an exciting and sometimes nerve-wracking age for parents. During this time of rapid growth and physical development, make sure to take your infant in for the regular checkups recommended by your pediatrician and to stay up-to-date on any immunizations.

Because so much is new for both parents and child, it is important to know when to call a doctor. Should your baby become ill, make sure that you are giving him or her medicine that is safe for children and administering the proper dose. Never hesitate to reach out to your child’s pediatrician if you have a question or concern.

During the first 12 months, you can promote healthy infant growth and development through frequent feedings, emotional bonding, a stimulating environment and addressing sibling rivalry. You should also address any household safety issues that could harm your baby. 

Learn more about your newborn's milestones:

Growth and Development

For the first several months, your newborn will only need breast milk or formula for proper nutrition. When your baby is able to sit upright in a highchair and begins showing interest in food, you can start transitioning your baby to solid foods with pureed foods and cereals (iron-fortified).

While every baby is different and will grow at his or her own pace, during the first year your baby will change dramatically in five areas of development: physical, cognitive, emotional and social, language, and sensory and motor skills.

Every baby is different. Always ask your pediatrician if you have questions or concerns.

Physical Development

By four months babies grow about 3 inches and gain an average of 4.5 pounds from their birth length and weight. Their head circumference also grows between .25 and .5 inches a month during the first year of life. By six months, their weight has usually doubled from birth, averaging a gain of .5 oz to 1 oz. a day. Growth may begin to slow around this time for infants and become more gradual. By their first birthday, babies have grown about 10 in. in length and their weight has tripled.

Some babies may begin teething at this age, with the first tooth coming in between four to 18 months.

Cognitive Development

While a baby’s cognitive ability and senses develop, his or her ability to interact with the people and environment around him or her increases.

Beginning around one to two months of age, babies will turn their head towards and take an interest in objects and people. By three months, this interest evolves into an ability to anticipate familiar things and to react to them.

During the fourth month of life, your baby's vision will improve, and most are able to link the senses of sight, taste, hearing and touch together to form an identity of one object or person, called sensory integration. Between six and nine months of age, babies begin to recognize those familiar sights, sounds and touches. They are also able to better understand absence and create memories, a skill called object permanence.

After gaining a better understanding of what is familiar, babies around nine to twelve months of age become more prone to watching others and exploring objects and environments. Personality, curiosity and emotion become more apparent during this age.

Emotional and Social Development

As infants at one month begin to better express their feelings (often with alert, widened eyes and a rounded mouth) the bond between parents and baby strengthens.By two months, your baby may begin to interact with you by smiling, called the “social smile,” along with making eye contact and moving arms. As early as two to four months, babies will grow attached to familiar caregivers.

At four to six months of age, babies become more social, and their facial expressions can now readily express emotion, such as anger and happiness.Between six to nine months, they will use those expressions to communicate both preference for caregivers and anxiety at their absence. They may cry, turn away or become upset when separated from caregivers, called separation anxiety, or act uneasy around strangers, called stranger anxiety.

Towards their first birthday, around nine to twelve months, separation anxiety and stranger anxiety may decrease, while babies increasingly demonstrate preference and affection for caregivers. Independence also increases as your baby may begin to explore more by crawling or even walking.

Language Development

While infants do not usually begin to speak in the first year of life, development of language skills does allow them to understand and to communicate with others. Although not yet understanding what's being said, around one month, infants will turn to a soft voice, especially that of a parent’s.

By three to six weeks, they begin to use certain cries to express different needs, such as hungry or sleepiness.

What we refer to as "baby talk” begins at two months with cooing, or “ih” and “uh” sounds. Babies may also watch speaking mouths and respond. Around five months, babies progress to babbling, or repeating sounds for attention and expression. They may even begin to recognize their name.

By six to nine months, infants will begin to imitate sounds and rhythms of speech. They may still babble to communicate but can also recognize the word “no,” respond when told to “wave bye-bye” and begin to understand simple commands.

By their first birthday, the words “mama” and “dada” can be tied to parents by infants and even used. The names of other family members or pets may also be understood when they hear them.

Comprehending more words by this age, babies will tend to jabber with tone and inflection that mimics conversation.

Sensory and Motor Development

As muscles begin to strengthen during the first month, most babies are able to lift their head for a short time while lying on their stomach. Other limb movements at this time may be due to newborn reflexes, such as the startle reflex, where a baby throws out his or her arms and spreads fingers when confronted by a loud noise or surprise. These reflexes begin to fade away by six weeks.

At three months, infants now have better control of their head and begin to appear fascinated with their hands. They will also now knowingly hold onto the fingers of others as a way to gain attention. Around four months, control and balance of their head, neck and trunk will allow them to begin to roll over.

Still unsteady at four months, babies might sit with their hands out front to balance them in a tripod position. However, by six to nine months, leg and trunk coordination have improved, allowing babies to sit, crawl and sometimes even pull themselves up to stand. At seven months, your baby's eyes have developed almost to the same extent as your own.

In the few months before their first birthday, more control over their hands and fingers let babies better grab small objects with their thumbs and index fingers, rather than their palms. As they start to learn and interact with all their senses, babies have a tendency to put objects in their mouth, making baby-proofing your home extremely important.

Until they are able to walk independently, babies will use furniture and other objects to pull themselves up and “cruise” around the room. Be sure to secure any heavy objects that could topple over, such as bookcases and dressers, and move any potentially harmful objects well out of reach.

Learn about the next age range: Toddler (2-4 Years).