Growth and Development, Ages 1 to 12 Months

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Children usually move in natural, predictable steps as they grow and develop language, cognitive, social, and sensory and motor skills. But each child gains skills at their own pace. It's common for a child to be ahead in one area, such as language, but a little behind in another.

At routine checkups, your child's doctor will check for milestones. This is to make sure that your child is growing and developing as they should. Your doctor can help you know what milestones to watch for as your child gets older. Or you can look for sources of information and support nearby. Public health clinics, parent groups, and child development programs may help. Knowing what to expect can help you spot problems early. And it can help you feel better about how your child is doing.

Talk with your doctor about any concerns you have about your child's health, growth, or behavior. Do this even if you aren't sure what worries you.

Your relationship with your child will change as your child gains new skills and develops independence. As your child's world gets bigger, you can help your child grow in healthy ways. Here are a few things you can do. Spend time together. Be a good role model. Show your child love and affection.

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What to Expect

A lot of changes occur during a baby's first year. Here are some of the things that may happen.

Physical development.

Babies steadily gain weight and grow in length throughout this first year, often in growth spurts.

Cognitive development.

This is how the brain forms its abilities to learn and remember. Babies soon start to recognize familiar people. They slowly realize that people and objects exist even when they are out of sight. They start to connect what they see with what they taste, hear, and feel.

Emotional and social development.

Babies form bonds with their parents and other caregivers. When cared for in a loving and consistent way, most babies start to engage and interact with others.

Language development.

Babies start communicating with different types of cries. Then they progress to babbling.

Sensory and motor skills development.

As your baby's brain, nerves, and muscles grow, controlled movements become more refined. Newborn reflexes gradually fade.

Milestones by age

Each baby grows and gains skills at their own pace. It's common for a baby to be ahead in one area, such as language, but a little behind in another.

By around 2 months, most babies:

  • Smile as a way to engage others.

By 4 months, most babies:

  • Start using their arms with purpose. For example, babies may move their arms and squirm when excited. Or they may "swipe" at dangling objects.

By 6 months, most babies:

  • Have doubled their birth weight.
  • Are able to sit with little or no support.

By 9 months, most babies:

  • Get upset when you or another caregiver leaves.
  • May have started to crawl.

By 12 months, most babies:

  • Have tripled their birth weight.
  • Are expressive and have formed a close attachment to their parents.
  • Understand some words and start to figure out the meaning of many others.
  • May be able to say a few words.
  • May be walking.

Premature infants typically reach milestones later than others of the same age. But they are usually on schedule for their expected time of birth. For example, a baby born 2 months early might reach milestones 2 months later than a full-term baby born at the same time.

Healthy babies who were born prematurely usually reach normal developmental levels for their age by the time they are about 24 months of age. Learning and thinking skills usually are first to catch up. Motor skills are often the last to catch up.

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Common Concerns

During the first 12 months of a baby's life, it's very common for parents to have concerns about their baby's general well-being. Know that you likely don't have anything to worry about. But it's good to be aware of health, development, and safety issues to help prevent or respond to problems.

Sudden infant death syndrome (SIDS)

SIDS is the death, without a known cause, of a baby who is younger than 1 year old. Typically, a parent or other caregiver puts the baby—who seems healthy—down to sleep and returns later to find the baby has died.

SIDS is very rare, and it can't always be prevented. But you can help prevent SIDS by taking certain steps. Until your baby's first birthday, always put your baby down to sleep on their back.


You may just start bragging to your friends and family how your baby is sleeping through the night when—suddenly—that's no longer true. The fact is, sleeping patterns change.

Your baby may suddenly start to cry when it's nap time or bedtime. Or your baby may wake up during the night. Sometimes a baby gets too excited for sleep after they've mastered some new skill, such as jabbering or shaking the crib. Other times, hunger from a growth spurt, a change in routine, or not feeling well may interrupt a good sleep pattern.

Try to keep a nap and bedtime routine. Your baby will adjust if you stay consistent. And remember, napping can be good for tired parents too.


You may notice that your baby's feeding patterns change during this time. Parents often wonder if their baby is getting enough nourishment. The quality and quantity of a baby's feedings probably are fine if the baby is gaining weight steadily, is content most of the time, and is becoming more and more alert and active.


Babies cry a lot, especially in the first 2 months. Crying is your child's first way of communicating.

The amount of time your baby spends crying usually increases from birth until your baby is about 6 to 8 weeks old. After that, most babies will gradually cry less as they find other ways of communicating or consoling themselves.

If your child is crying, try to identify the type of cry. It helps to go through a mental checklist of what might be wrong and make sure your child is safe and cared for.

As you respond to the young child's other signals (such as whimpering, facial expressions, and wiggling), the child will usually cry less.


Babies love to put objects into their mouths. To keep your baby from choking:

  • Be careful about the size of toys your baby plays with.
  • Watch out for everyday items that your baby could swallow, such as coins.
  • Be careful as you start to give solid foods to your baby around 6 months of age. Help prevent choking on food by not giving your child round, firm foods, such as hot dogs, unless you first completely chop them into very small pieces.

Diaper rash

Diaper rash occurs most often in babies who are 9 to 12 months old. Even though a diaper rash is uncomfortable, normally it isn't serious. Usually the rash clears up when you:

  • Change diapers more often.
  • Are careful about cleaning your baby's bottom.
  • Apply nonprescription ointments to the rash.


Your baby is teething when the first teeth break through the gums. Teething usually begins around 6 months of age. But it can start at any time between 3 months and 12 months of age. Your baby may show signs of discomfort from sore and sensitive gums, be cranky, drool, and have other mild symptoms for a few days before a tooth breaks through the gum.

Sibling rivalry

It may take a few months before an older child shows signs of jealousy of a new baby. When your child realizes that the baby is there to stay, strong emotions and behavior problems may soon follow.

You can take steps to prepare for sibling rivalry. For example, you can:

  • Help your older child adjust by setting time aside for just the two of you.
  • Talk about how important it is for your older child to help care for the baby.
  • Give your older child a role in daily care, such as handing you a fresh diaper when you change your baby.

Separation anxiety

Starting around 6 months of age, your baby begins to feel uneasy when you go away. Starting around 9 to 12 months of age, your baby may cry and react strongly when you leave. This is called separation anxiety, or separation protest. You can help your baby manage these emotions by making sure that your child is well-rested and well-fed before you leave. It may also help to distract your baby, such as with a favorite toy.

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Promoting Healthy Growth and Development

A baby goes through so many changes that it can be hard for you to keep up with all the things experts say you "should be" doing to promote healthy growth and development.

Remember that the best things for your baby are usually the simplest. Loving, holding, changing diapers for, talking to, and feeding your baby are the things to focus on.

But you can always learn more about how to help your baby grow and develop in healthy ways.

  • Try to breastfeed.

    Experts recommend feeding your baby only breast milk for about 6 months. They also support breastfeeding for 2 years or longer.footnote 1 But your baby benefits from any amount of time that you breastfeed. Try to breastfeed for as long as it works for you and your baby.

  • Learn your baby's rhythms.

    You will gradually get a sense of your baby's unique sleeping and eating patterns. You will be able to help establish a routine by the time your baby is about 3 months of age. But be prepared to make adjustments as needed.

  • Help keep your baby's head from getting too flat.

    It's important to always put your baby to sleep on their back. But always sleeping on the back may make your baby's head a little flat. You can help keep it from getting too flat by changing your baby's head position regularly.

    • Allow your baby "tummy time" while your baby is awake and you are closely watching. Tummy time also helps your baby develop motor skills.
    • Cuddle your baby while holding their head up as much as you can. Don't place your baby in car seat carriers or bouncers for long periods each day.
    • Change your baby's head position during sleep at least every week. (Remember to always keep your baby on their back during naps and at bedtime.) A good way to make sure your baby's head rests in different positions is to switch which end of the bed you place your baby in each week. Babies usually turn their heads away from the wall, toward the inside of a room.
  • Care for your baby's teeth.

    Start to care for your baby's teeth as soon as you see the first baby tooth (primary tooth).

  • Keep your baby safe.

    Keep your baby safe from injury, drowning, burns, poisoning, and other dangers.

  • Choose child care wisely.

    Before you take your baby to a child care center, check the health policies of the center. Get the names of people and agencies you can talk to about the care center's safety record.

  • Encourage bonding.

    Consistently interact with and provide loving attention to your baby.

  • Recognize and reinforce behaviors.

    For example, when you interact with your baby, encourage smiling and eye contact.

  • Respond to crying.

    Your baby cries to communicate needs, such as feeling hungry or uncomfortable. You aren't spoiling your baby by promptly responding to these cues. Use comforting techniques, like cuddling and singing.

  • Stimulate learning.

    You help promote your baby's cognitive development through emotional bonding, interaction and play, and unconditional love.

  • Nurture speech and language development.

    Talking to, interacting with, and reading to your baby are all natural ways to promote language development.

  • Don't spank your baby.

    Don't spank your baby or use other types of corporal (physical) punishment. A baby age 1 month to 12 months is too young to know that there are certain ways they should behave. Try distracting a child who is doing something wrong or something that might be dangerous. For example, if your baby tries to pull the dog's tail, you can find a toy to get your baby's attention. Then move the dog to another area.

  • Don't worry about "spoiling" your baby.

    You can't spoil a baby at this age. Hold your child, and give them as much love and attention as you can. Your love and patience are critical for helping your child grow into a happy and confident toddler.

Parenting help

Taking care of your baby is an exciting time, but it can also be stressful. Some days you may simply feel overwhelmed. Ask for help when you need it.

  • Call a family member or friend to watch your baby and give you a break.
  • Investigate community resources that are available to help you with child care or other needed services.
  • Call a doctor or local hospital for some suggestions.
  • Find an online support group for parents.
  • Find a respite care facility.

    Some communities have respite care facilities for children. This is a place that provides temporary child care during times when you need a break.

Parents may also find that they have a harder time communicating with others. Feeling tired can make you more sensitive and lose patience more easily than normal. Learn coping skills to help you deal with anger and frustration. Call 1-800-4-A-CHILD (1-800-422-4453). They can guide you through a stressful time.

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When to Call a Doctor

Call 911 or other emergency services if you become so frustrated with your child that you are afraid you might cause your child physical harm.

Talk to your doctor anytime you have concerns about your baby's:

  • Physical development. (For example, call if your baby's growth seems to slow significantly or if your baby isn't consistently eating well.)
  • Cognitive development. (For example, call if your baby is not becoming more alert or active over time.)
  • Emotional and social development. (For example, call if you are concerned about how you and your baby interact or if you feel unable to nurture or emotionally connect with your child.)
  • Language development. (For example, call if your baby doesn't babble as expected or respond to your voice.)
  • Sensory and motor skill development. (For example, call if your baby doesn't consistently meet motor skill milestones, such as purposeful rolling over or crawling.)

Also see your doctor if your child has lost a skill that was previously mastered.

Routine Checkups

Doctors recommend that babies have routine well-child visits every 2 to 3 months from age 1 month to 12 months. During these visits, your doctor checks your baby's growth and development to see if your baby is reaching the milestones for each specific age. During these visits, you also can discuss any concerns you have. When your baby is age 9 months, the doctor may do a developmental screening test.

At every checkup, the doctor:

  • Looks at your baby's physical growth by measuring weight, length, and head circumference. These measurements are placed on a growth chart and are compared to previous and later markings to make sure that your baby is growing as expected.
  • Asks you about your baby's motor and sensory development, vision, and hearing. Your baby receives a thorough exam and gets immunizations.
  • Assesses your baby's emotional and social development by observing your baby's interactions with you. You will be asked questions about how you and the rest of the family are doing, how your baby is eating and sleeping, and whether you have noticed any changes in behavior.

The doctor will be especially interested in certain developments at specific ages. For example:

At 2 months:
  • Is your baby smiling yet?
  • Do you have a routine feeding schedule?
  • Are you bonding with your baby?
  • Is the rest of the family adjusting to the baby?
At 4 months:
  • Is your baby reaching and grasping?
  • Does your baby try to bring objects to their mouth?
  • Are crying spells getting shorter?
  • Is your baby settling in with the family? And is your family enjoying the baby?
At 6 months:
  • Is your baby able to sit?
  • How are your baby's sensory and motor development and hand-eye coordination?
At 9 months:
  • How is your baby eating?
  • Is your baby able to pick up objects?
  • Does your baby respond to their name?
At 12 months:
  • Does your baby walk while holding on to furniture?
  • Does your baby enjoy playing peekaboo or patty-cake?

Routine checkups are a good time for parents to ask about what to expect in the weeks to come. You may find it helpful to keep a list of questions to ask the doctor.

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  1. American Academy of Pediatrics (2022). Policy statement: Breastfeeding and the use of human milk. Pediatrics, 125(1): 1–15. DOI: 10.1542/peds.2022-057988. Accessed July 18, 2022.


Current as of: October 24, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

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