12 Week Old Baby Development

Learn everything you need to know about your 12 week old baby. Track important developments and milestones such as talking, walking, growth, memory & more.

12 week old baby

Your Growing Baby

Bigger Baby Belly = More Sleep For Mama

The milestone you've been waiting for: At 3 months old, your baby's tummy is finally big enough to store enough food to get him through five (or more!) hours without snacking. That means that one of these days your baby could start sleeping through the night—or at least give you enough of an uninterrupted stretch of Zs that you feel less zombie, more human. But if you've still got a night owl, help him get there with these sleep-promoting steps:

  • Make sure he's not napping too often during the day or for more than three hours at a time since it might prevent him from conking out at night.
  • Try giving him a bit more to eat right before bed.
  • Don't dash into the nursery the second you hear him crying (and leave his diaper alone unless he pooped).

Letting your baby cry it out is easier said than done, but it's all about helping him learn to nod back off on his own. And as long as you're rushing in there to pick him up, he'll count on you to do so. Let him go for a little while—at least five or ten minutes—to see if he can drift back off before you offer up some Mommy or Daddy comfort.

By this week your baby can probably lift his head up 90 degrees when he's on his belly. He's also getting good at remembering things. He'll smile when you walk into the room—a clear sign of recognition—and he loves repetition, such as listening to the same books over and over or following the same daily sleep-play-eat routine. This actually helps boost memory and brain function, so keep it up!

Health and Safety Info

Babyproofing Must-Knows

Your baby isn't getting around on his own yet, which makes now the perfect time to start babyproofing. You don't have to go nuts with the full panoply of toilet-seat locks and padded coffee-table corners yet—you've got a few months before crawling or cruising will begin. But you might want to put away valuables or breakables he could get his hands on, such as picture frames on an end table within striking distance of his swing.

He'll also soon master the ability to spot and grab small objects on the carpet —lost coins, bits of lint, petrified pieces of rice from dinner two weeks ago—and shove them in his mouth. In part that's because he's beginning to really adore his own hands—waving them around, bringing them together in a clap, and wiggling his fingers. So while it's great that he can grab a toy, dust bunnies are a different story. Before you set him on the floor for tummy time, do a quick scan to make sure there's nothing harmful he can jam in his mouth while you're not looking. Get even safer by lying on your stomach next to him and looking around from your baby's perspective. You'll spot things you'd never notice otherwise (Hey, how'd that bottle cap get under the couch?) and keep your baby safe from choking hazards.


Pumping Tricks & Tips

If you're nursing—and heading back to work—you'll want to keep these dos and don'ts in mind when it comes to pumping:

  • Do try out your pump before you head back to the office (it takes some getting used to).
  • Do buy a small cooler bag and cold packs to keep the milk chilled during your commute home. You'll also need plenty of milk storage containers.
  • Don't forget to mark each container with the date the milk was pumped; otherwise they can get mixed up in the fridge or freezer.
  • Do secure a place to pump now, if you don't have your own office. (Make sure the door locks!) Keep in mind that you'll need a power source if you're using an electric pump.

If you're planning to pump, start now so your body can adjust, your baby can get used to the bottle and being fed by non-Mom types, and you can start building up a stockpile of frozen milk. Not only does it give you some backup— in case you have a meeting and miss a pumping time during the day— it also gets you accustomed to using your pump. Plus, having some extra bottles handy in the fridge means you can escape with your hubby for a quickie dinner, or even just hit the gym on your own while Grandma watches the baby. A little freedom goes a long way.

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