Somehow that tiny, sleepy little newborn is now (or about to be) a 3-month-old baby! With each passing week their personality shines brighter, their awareness increases and their brains and bodies get stronger. At 12 weeks old, baby is making connections at breakneck speed, building those neurons and feeling more and more at peace in their environment, not to mention smiling and engaging more than ever as the people in their life fall more and more in love with them. Here’s what to expect from 12-week-old baby milestones.
12-Week-Old Baby Milestones & Development
Buckle your seatbelts; it’s time for another growth spurt. By now you’ve likely experienced one or two of these bursts and all that can come with them: increased hunger and fussiness, changes in sleep patterns and the strange sensation that when you pick them up in the morning, they suddenly feel heavier. Take comfort in the fact that these periods usually last no more than a few days.
Some days your 12-week-old baby will do more growing than other days, but it all averages out to a gain of about 1 ounce a day and 1 inch a month. Their head circumference will increase by another centimeter or so this month as well. If they weren’t already in the next size of clothing, it’s likely that it’s time to put away the 0 to 3 month size and bring out the 3 to 6 month outfits.
So what 12-week-old baby milestones should you be on the lookout for? Baby is getting stronger and is now probably able to lift their head and chest up when they’re on their tummy. Some little ones this age are even starting to try to roll over. Though they probably won’t consistently reach this milestone until they’re 4 to 6 months old, it’s more important than ever to not leave them unattended on a bed or changing table.
When you’re holding baby, they can now support their own head, and if you hold them on a surface, they’ll push their feet down to stabilize. In the coming weeks, baby may even be able to sit up with support.
At this age, baby is probably pretty interested in their hands as they open and shut them, bring a hand to their mouth, kick and swipe at dangling objects and can finally grasp and shake that rattle you keep offering them.
At 12 weeks old, baby doesn’t miss a thing; they’re watching faces closely, following moving objects with their eyes and recognizing familiar things and people at a distance. They’re becoming more coordinated and are starting to use their hands and eyes in sync. Baby is also probably turning toward sounds, beginning to babble and even imitating some basic sounds.
If they haven’t gained all of these skills yet, it’s likely you’ll be seeing these by the end of the month. If they aren’t responding to sounds, smiling, tracking with their eyes or bringing hands to mouth at 12 weeks, it’s worth flagging these concerns at the upcoming well visit.
12-Week-Old Baby Health
Baby is probably eating about the same amount as the last few weeks (unless they’re actively going through that growth spurt), but the biggest difference now is their efficiency. Breastfed babies in particular will likely have picked up speed as they’ve gotten the hang of things. A feeding may have taken up to an hour when they were itty bitty, but at 12 weeks it may take half that or even less. How much should a 12-week-old baby eat? About 4 to 5 ounces per feeding every three to four hours is typical.
For the last three months you’ve probably been told to hold and feed baby as often as they want, but at 12 weeks it can feel like the expectation suddenly shifts as advice streams in to get them on a sleep schedule and sleeping through the night. But don’t stress. If your child goes down easy and sleeps six to eight hours overnight, then keep doing whatever you’re doing (and try not to brag to your overtired parent friends). If not, take comfort in knowing that even by 6 months, only two-thirds of babies are sleeping through the night.
Your 12-week-old baby should be getting around 15 total hours of sleep, with nine to 10 of those overnight and four to five during the day.
You may or may not have noticed that baby’s Moro reflex is starting to disappear, meaning there’s less need for swaddling—which is good, since it’s time to transition to a sleep sack or other option now that baby may begin rolling soon.
Common cold As much as we try to protect our kids, they’re bound to get sick from time to time. The common cold is one of the most, well, common childhood illnesses, and typically isn’t dangerous. If your 12-week-old baby has a fever of 100.4 or higher, give the pediatrician a call. In most cases, the cold will go away on its own, so you can do your best to treat the symptoms. If baby is congested, then a nasal aspirator can help clear them out. Most importantly, keep them well-hydrated with breast milk or formula.
COVID Although babies are less likely to contract COVID-19 than adults, it’s certainly still possible; since the start of the pandemic, almost 15.4 million babies have tested positive (about 18 percent of the total). Since babies younger than 6 months have immature immune systems, aren’t eligible for the vaccine, can’t wear a mask and are at higher risk of complications, it’s important to take special care should your 12-week-old baby test positive for COVID. Like adults, babies can be symptomatic or asymptomatic, but regardless, call your pediatrician immediately if they test positive. If their recommendation is to stay home, then follow standard quarantine procedures, try to keep baby away from healthy members of the family and keep them hydrated. If breastfeeding, keep up with it, since this will help boost their immune system. Family members who test negative for COVID but are still caring for baby can mask in their presence to reduce the risk of transmission.
12-Week-Old Baby FAQs
When can baby get a COVID vaccine?
You may be wondering when your little one can get vaccinated against COVID. Both the Moderna and Pfizer coronavirus vaccines are recommended by the American Academy of Pediatrics (AAP) for babies aged 6 months and older—so the answer is soon, but not yet!
How early can I sleep train baby?
There isn’t a clear consensus on when to sleep train baby, but some pediatricians suggest starting when baby is around 4 months old. If you’re considering it, check in with your child’s doctor to make sure there aren’t any medical reasons to hold off, and then read up on the different methods to find one that jives with your parenting approach. Keep in mind that every book and blog you read will present their method as the best one, and oftentimes their advice goes against one another. For an already sleep-deprived parent, this can make you feel like you’re losing your marbles. Just focus on finding something that works for you. Take it slow, and know that one way or another, your child will eventually sleep.
Timely 12-Week Topics
When will baby start to roll over?
Rolling over is a pretty exciting milestone because it’s one of the first big physical developments that reminds parents that mobility is just around the corner. Babies typically start consistently and purposefully rolling from stomach to back when they’re 3 to 4 months old. It may happen a few times before that, but it’s usually a fluke. It’s generally a bit harder for babies to roll from their back onto their tummies, and often takes them an extra month or so to get a handle on that direction.
Now more than ever, it’s critical that you never leave baby unattended on any surface above the ground, for even a second. Also, make sure the area around them is clear when they’re doing tummy time, since they may roll over at any moment. The first few times they do it they may be so surprised that they burst into tears, but rest assured that they’ll keep going and get used to it in no time.
Returning to work
If you’ve gone back to work or are gearing up for the return, you’re probably having a lot of mixed emotions about the end of parental leave—perhaps excited, sad and stressed. Whatever your feelings are, they’re completely valid. It’s a big transition! Make it easier on yourself by making sure you have all the necessary supplies: A portable pump, breast milk storage bags, perhaps a cooler to keep your milk cold on long commutes, maybe some breast pump cleaning wipes if you don’t have access to a sink. If you’re experiencing feelings of guilt, reframe the narrative in your head (earning an income, spending time with other adults and stimulating your mind are all good things for you and your family) and focus on quality time with baby over quantity. If you’re feeling overwhelmed with your lengthy to-do list, try some mindful breathing exercises. Above all, give yourself grace as you navigate this new phase.
Keep an eye out for paternal postpartum depression. It’s not only new moms who are susceptible: Up to 25 percent of dads suffer from postpartum depression in the first six months, with one study showing the highest rate of paternal PPD between three and six months after baby’s birth. Possible signs could include increased irritability, decreased motivation, loss of interest in activities, fatigue or lack of engagement with their child. The transition to parenthood is a huge one and impacts everyone differently. A professional therapist can help get to the bottom of these issues and offer some helpful coping strategies.
Put yourself out there. There’s no denying that having a kid changes things. While you can and should maintain friendships with your pre-parenthood friends, it’s also important to nurture new relationships with people who are going through the same stuff as you in real time. It can feel as awkward as dating to put yourself out there, but there are plenty of ways to make new parent friends. Check Facebook for any local playgroups, head to family events in your neighborhood, strike up a conversation with fellow parents at the playground or ask family and friends for introductions. You’ll be glad to have a friend who’s just as eager to discuss sleep challenges and weird baby behaviors as you!
Products You Need at 12 Weeks
Toys for a 3-month-old. Stock up on some developmentally appropriate playthings that’ll stimulate baby’s senses and help promote their motor skills. These are our favorite toys for a 3-month-old.
Crib. If you haven’t yet made the transition from bassinet to crib, the time is fast approaching. While many expectant parents have this set up before baby even arrives, others wait until they need it. These are some of our favorite cribs.
Crib mattress. The type of crib mattress you pick is important, not just for baby’s comfort, but also for their safety. Find something that’s breathable, firm and fits snugly in the crib frame.
Crib sheets. A fitted crib sheet is the only type of bedding that should be in baby’s sleep space. We love these soft, chic and safe options!
Weekly Activity for Your 12-Week-Old Baby
It may sound silly to have a conversation with an infant who doesn’t yet talk, but it’s actually the perfect time to start practicing with your 12-week-old baby. Now that they’re beginning to babble and mimic sounds, their communication skills are taking off. When baby starts babbling, wait for them to pause, then respond with words. You can comment on the sound they just made, ask them a question or ponder what outfit they’d like to wear today. Then look expectantly at your child with a big smile on your face; chances are, they’ll wait their turn and respond with some enthusiastic babbles. Keep going as long as this “conversation” persists. Research shows that babies who experience this kind of back and forth have bigger vocabularies later on than those who don’t.
Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.