Baby milestonesthe first year, month by month

How CDC's milestone checklists work

The CDC's Learn the Signs. Act Early. program publishes free, downloadable checklists that describe what many babies can typically do by a given age. The checklists cover four areas: social/emotional, language/communication, cognitive (learning, thinking, problem-solving), and movement/physical development.

An important detail most parents never hear: CDC places each milestone at the age by which at least 75% of children are expected to be doing it. That means the checklists describe a normal range, not a rigid pass/fail exam. CDC is explicit that these milestones "are not developmental guidelines or standards" — they exist to start a conversation with your child's doctor, not to replace one.

In your baby's first year, CDC publishes checklists at 2, 4, 6, 9 and 12 months. Below is what each one covers, drawn directly from CDC's current published checklists.

Milestones by 2 months

By around 2 months, many babies:

• Social/emotional: calm down when spoken to or picked up, look at your face, seem happy to see you when you walk up, and smile when you talk to or smile at them.
• Language/communication: make sounds other than crying and react to loud sounds.
• Cognitive: watch you as you move and look at a toy for several seconds.
• Movement/physical: hold their head up when on tummy, move both arms and both legs, and open their hands briefly.

Milestones by 4 months

By around 4 months, many babies:

• Social/emotional: smile on their own to get your attention, chuckle (not yet a full laugh) when you try to make them laugh, and look at you, move, or make sounds to get or keep your attention.
• Language/communication: make cooing sounds like "oooo" or "aahh", make sounds back when you talk to them, and turn their head towards the sound of your voice.
• Cognitive: open their mouth when they see a breast or bottle if hungry, and look at their hands with interest.
• Movement/physical: hold their head steady without support when held, hold a toy placed in their hand, swing at toys with an arm, bring hands to mouth, and push up onto elbows or forearms when on tummy.

Milestones by 6 months

By around 6 months, many babies:

• Social/emotional: know familiar people, like to look at themselves in a mirror, and laugh.
• Language/communication: take turns making sounds with you, blow "raspberries", and make squealing noises.
• Cognitive: put things in their mouth to explore them, reach to grab a toy they want, and close their lips to show they don't want more food.
• Movement/physical: roll from tummy to back, push up with straight arms when on tummy, and lean on their hands to support themselves when sitting.

Milestones by 9 months

By around 9 months, many babies:

• Social/emotional: are shy, clingy, or fearful around strangers, show several facial expressions (happy, sad, angry, surprised), look when you call their name, react when you leave by looking, reaching, or crying, and smile or laugh during peek-a-boo.
• Language/communication: make a lot of different sounds like "mamamama" and "bababababa", and lift their arms up to be picked up.
• Cognitive: look for objects when they're dropped out of sight, and bang two things together.
• Movement/physical: get to a sitting position by themselves, move things from one hand to the other, use their fingers to "rake" food towards themselves, and sit without support.

Milestones by 12 months (1 year)

By around 12 months, many babies:

• Social/emotional: play games with you, like pat-a-cake.
• Language/communication: wave "bye-bye", call a parent "mama", "dada" or another special name, and understand "no" (pausing briefly or stopping when you say it).
• Cognitive: put something in a container, like a block in a cup, and look for things they saw you hide, like a toy under a blanket.
• Movement/physical: pull up to stand, walk while holding on to furniture, drink from a cup without a lid as you hold it, and pick things up between thumb and pointer finger.

Keeping a simple running note of what you notice each month, in a place like journal and insights in Mommy Refuel, can make it much easier to describe changes accurately at the next check-up rather than trying to remember everything on the spot.

When to talk to your pediatrician

CDC's core message is Act Early, not wait and see. Talk with your child's doctor and ask about developmental screening if:

• Your baby is not meeting one or more milestones for their age.
• Your baby has lost a skill they used to have.
• You have any concern at all about how your baby plays, learns, speaks, acts, or moves, even if you cannot point to a specific missed milestone.

CDC is clear that a missed milestone is not a diagnosis and does not mean something is wrong. It is simply a reason to bring it up, so screening and, if needed, early support can start sooner rather than later. Your pediatrician, and CDC's free Milestone Tracker app, can help you go through the full checklist in more detail.

A note on what this article can and can't do

Mommy Refuel is a wellbeing app for parents, not a medical provider, and this article is general information rather than medical advice. It cannot assess your individual child's development. A daily check-in and journal can help you notice patterns and put specific, dated observations in front of your pediatrician, and a visit summary can make those notes easier to bring to an appointment, but only a qualified health professional can evaluate whether a delay needs follow-up.