Development Milestones In Your Baby’s First 18 Months

Your baby may not seem like they’re doing much beyond sleeping and eating, but their little body is busy growing at warp speed. (Not to mention, they’re on a crash course learning about the world around them.) For instance, their weight usually doubles by the time they’re five to six months, and triples by the time they’re a year old. Along the way, they’ll hit important infant milestones. Of course, every baby is their own person, yet there are general stages of development they’ll go through, which tend to occur around certain ages. 

Below, we’re taking you on a journey through your baby’s milestones in the first year and a half. Fun fact: Infant milestones are based on your due date, not the day your baby was born. So, if your little one was a preemie (born before 37 weeks), be sure to take that into account and add those weeks back into the timeline. And remember, try not to fret if your infant’s development doesn’t precisely line up. It’s common for babies to lag behind in some areas and accelerate through other baby milestones. If you’re concerned, though, always consult your pediatrician. 

What Are The Stages of Infant Development?

Infant development milestones refer to when your baby starts doing little human things. These include advancing in their movements, intelligence, emoting, and interactions. Think better control of their wobbly noggin and wayward limbs, their first heartwarming smile and “mama,” their first cruise around the living room floor, and getting the hang of walking. They are quite literally baby steps, and they tend to occur every few months. Read on to learn what infant development milestones tend to be by age. 

2-month infant milestones: Around two months old, your baby will likely begin making their first strides in their motor development. You’ll start to notice them moving a little smoother and lifting or turning their head. You can help their progress along by doing things like “tummy time,” where you lay them down on their belly. This will encourage them to start trying to do little baby push-ups to lift off the floor and strengthen those itty bitty muscles.

They’ll also start vocalizing (aside from crying) by making little cooing and gurgling sounds. However, they will cry or become fussy if they’re bored—hey, nobody likes a waking snooze fest. Things start to catch their attention, like people or toys, and they may even be able to recognize people from a distance. All of a sudden, faces amuse them. The best parts, their eyes will start to search for you, they can briefly calm themselves down with a good ‘ol baby hand in mouth, and you may start to see their adorable chubby smile. Heart. Melted.

Then there’s the fact that, as you may have already noticed, your baby is a little toot machine. In their first few months of life, your baby’s immature digestive system tends to be pretty gassy. Your little one may also swallow too much air while feeding or crying, or they may have sensitivities to your breastmilk (due to your diet) or certain ingredients in formula. Be prepared for gassy bouts by keeping Infants’ Mylicon Gas Relief drops in either the dye-free or original formula around. They’re a safe way—even for newborns—to help quickly break up gas bubbles and help your baby naturally release them. And, no worries, the medicine in our gas drops won’t stay in your infant’s system—it’s not even absorbed.

To promote healthy digestion and boost your baby’s immunity, try giving them Infants’ Mylicon Daily Probiotic Drops, which help replenish “good” bacteria in their tummy. Bonus: If your infant is colicky, our probiotics can help reduce daily crying and fussiness by 50% or more over time when given daily!

(Read more about Why Babies Benefit From Probiotics.)

4-month infant milestones: By around four months old, your baby will probably have mastered the art of holding their head up, steady and unsupported, and pushing against things with their arms and legs. This leads them to rolling over from their belly to their back. They’re hand and eye coordination will also be coming together, allowing them to start holding and playing with toys.

Faces are now not only amusing, they’re worth studying. If your baby is happy or sad, they’ll be sure to let you know. Your infant will likely also start to cry in different ways for different reasons, such as hunger or sleepiness. (Psst: Get the 411 on How To Calm Your Crying & Fussy Baby.) Fortunately, this is also when they’ll start responding to your affection and enjoying playing with you. They may even begin mimicking your facial expressions. Cherubic smiles will also burst forth more, especially when they see people, and they’ll begin to babble expressively and copy sounds they hear.

6-month infant milestones: At about six months, those motor skills are really starting to gear up. Your little one may be able to roll all the way around. They’ll start to stand with some support and may bounce to their own little jig. If you plop them down on their little tushies, they’ll start being able to sit without any support. This is also around the time when you can start introducing solid food.

Curiosity in their surroundings will begin to emerge. Not only will your baby start looking around more, now, seemingly everything within reach starts going straight in their mouth, too. (Be extra careful, as always, not to leave small or dangerous objects nearby.) Those little hands are also getting more coordinated, so they may start passing things from one hand to the other.

Your baby will become more engaged and playful with people—especially you—and can even tell the difference between familiar faces and strangers. Their own face they’ll delight in seeing in a mirror. They’ll start responding to other people's emotions—good and bad—and react to sounds with sounds of their own. This is when they’ll start stringing varying vowels together, trying out consonants like m’s and d’s, and particularly, enjoying taking turns making sounds with you. Recognizing and responding to their name is also coming about.

9-month infant milestones: Pulling themself up to stand is a grand achievement around nine months, as is getting up into a sitting position by themself and starting to crawl. (Just be sure to watch them carefully, some babies are surprisingly fast on all fours.) Fine motor skills are now developing, and they’ll start being able to grasp small objects or morsels of food between their fingers. They’ll also be better at shifting things from hand to hand. If they see you hide something, they’ll look for it, making this the ideal time to start playing peek-a-boo with each other and truly blow their mind.

Whereas previously they learned to recognize strangers as strangers, now your baby may become a bit fearful of them and seek out your reassurance. Their vocalizations become more varied and they’ll mimic sounds and gestures. Your baby will also start pointing at things and discovering their favorite toys. They’ll likely understand what “no” means, but that doesn’t mean they’ll always listen to it—a cold hard fact that all of us parents learn.

12-month milestones: They’ve done it, yay! Your baby is now a year old and you can’t believe you’ve both come this far. Their first steps are imminent around this time, and your baby may even be able to stand on their own and “cruise” around the room while holding onto furniture. Then, with your encouragement, they’ll muster the courage to venture out on their chubby little wobbly legs. And, thanks mom, but they can get seated all on their own now. 

With this newfound physical freedom, your baby will also start exploring their world in different ways, like shaking things, or the less enjoyable, banging and throwing. Containers become fascinating: I can put things in and take them out, and put them in . . . They also start to use objects appropriately, like drinking from a sippy cup or brushing their own hair (kind of). No more do hidden things seem to disappear into thin air; now, your baby can hunt for them like a pro.

Your baby can now hand you a favorite book—and repeat their sounds and actions until they get your attention. They can point to the correct picture of an object when asked, as well as respond to other simple requests. You’ll also have a little helper while dressing them, because they may stick out an arm or leg to assist you. Patty-cake becomes a fun game to add to your repertoire, and your baby may start to show a preference for specific people in addition to you.

Mommy Pro Tip: Be sure to enlist those favored people for help when you’re away—this is also the age when your baby will start crying when they see you leave.

Little hands and fingers will begin to wave bye-bye (though it’s surely the last thing they want you to do), and not only can your baby understand the word “no,” they’ll be able to shake their head to tell you the same thing. Your baby will also be experimenting with saying the same words you do, and may use precious expressions, like “uh-oh.” Around this age is also when you may hear “mama” or “dada” for the very first time—music to your ears. 

18-month infant milestones: You’ve both come a long way. Now, your baby has graduated to using a spoon, and can help undress themself. They’ve also got places to go, since they can walk on their own—and run, as well as trail toys behind them in their travels.

You're now creeping up on the “terrible twos,” but starting around 18 months is when your baby’s new found autonomy can lead to the occasional temper tantrum. Thankfully, they’re also becoming more affectionate, so it should be hard to stay frustrated with them for too long. They’ll engage more by pointing out things they find intriguing, initiating play, and engaging in simple pretend games, like putting a baby doll to sleep.

By now, your baby is growing up and can say a few words, as well as recognize ordinary objects, such as your cell phone and shoes. They’ll also be able to follow single step directions, including “eat” and “lay down”—though the former may become a little more difficult if they’re a picky eater.

Now that you know what milestones are important for your baby, you can use the CDC’s handy Milestone Tracker App to help keep tabs on their progress up to the age of five.

Next: Have another bundle on the way? Learn How To Prepare Your Older Child For a New Baby.