Many parents assume that developmental milestones should be sequential. But infant milestones are not distinct achievements that children hit, unlocking abilities as if leveling up in a video game. Some babies arrive at 4-month milestones early, while hitting other milestones late. Some babies may leap over a milestone entirely. There’s no reason for parents to stress out over most developmental milestones — it’s always best to look at a child’s development from a holistic perspective, rather than through a subset of specific skills. After all, your 4-month-old isn’t just an avatar collecting a bunch of cool skills — even if cool skills develop in droves at this age.
In the fourth month of life, infants become natural experimenters, and while their experiments can be disruptive — “What happens when I drop my pacifier this time?” — they are important. By 4-months-old, babies start to learn about their world and show you what they know.
4-Month Milestone #1: Baby Should Be Communicative
Baby communication is a bit more subtle than you might imagine. Absent the capacity for language, your kid has to rely on the tools they do have to try and get your attention. What are they? Crying, cooing, grabbing, dropping, kicking, giggling, making faces, and looking.
These methods of communication aren’t always pleasant. Picking up the dropped toy gets old somewhere around the 10th time, and crying is never fun. But these behaviors are important because they signal your baby has developed some important skills. Smiling at you to get you to smile back means they are becoming aware of their personhood. Dropping objects for you to pick up means they’re gaining an understanding of cause and effect. Watching your face and listening to your voice before making their own response means that they are beginning to understand your emotions.
When a baby becomes more communicative, in their special baby way, it means that their motor development and cognitive development are beginning to work in concert. And as these systems come together, they are beginning to connect your baby to a wider world outside themselves. Most important, not every baby will communicate in the same way. Look for your baby’s special mode of communication.
Red Flags: If your baby isn’t following objects with their eyes, or doesn’t vocalize or react to your face by 4 months, it could be indicative of an issue with cognitive development. While there’s no reason to be terribly worried if your baby’s health is otherwise sound, it’s definitely something you’ll want to discuss with your baby’s pediatrician
What You Shouldn’t Stress About: Being communicative does not mean that your baby will be signing or saying actual words. Mostly, they’ll just want to make sure they have your attention. Give it to them, for sure, but also let them lead. There’s no sense in trying to teach them more words through DVDs or flashcards. Those things won’t help. Just talk to them as you normally would.
4-Month Milestone #2: Baby Should Be Stronger
Physically, typical babies’ motor systems seem to “turn on” in a specific way — from head to toe and from the middle of their body outwards. Which is to say they develop control and dexterity over these systems in a top-down, middle-out manner. As they practice using all these muscles, from neck-to-core to legs, and from arms to hands to fingers, they will become stronger.
It’s not as if your baby will be lifting weights at 4 months, but they should be using their systems in concert in order to explore their world. They might push themselves up and be able to reach out during tummy time. They might keep their arms taut and pull as parents help them into a sitting position. They will look fairly stable and be able to look around freely, reaching out to play and explore. And when parents hold them in a standing position they should be strong enough to support their weight without their knees buckling.
Red Flags: A baby with erratic movements who does not seem to have control over their head may not be developing typically. Babies who are struggling with physical development might have a tendency to keep their limbs tucked up and may simply seem listless and floppy.
What You Shouldn’t Stress About: At 4 months, there’s no need for your baby to need to know how to roll over. If they are otherwise strong and alert, the movement will eventually come, as will the ability to sit independently and eventually move around on their own.
The Baby Milestones That Matter
There are fewer developmental milestones in the first year of your baby’s life than you might think. Here’s your month-by-month guide.
- The Only 1-Month Milestones That Matter
- The Only 2-Month Milestones That Matter
- The Only 3-Month Milestones That Matter
- The Only 4-Month Milestones That Matter
- The Only 5-Month Milestones That Matter
- The Only 6-Month Milestones That Matter
Non-Milestone Moments in Baby’s Fourth Month
Four-month-olds should be taking a couple of naps during the day along with a full night of sleep. That’s good news, but keep in mind that sleeping through the night doesn’t mean soundless sleep. They will naturally wake between sleep cycles just like adults. So before you rush in, see if they can settle on their own.
Also, take a look at your baby’s eyes. Weirdly, the color might be changing a bit, and you may not know what color their eyes will settle on for a few more weeks. This is natural, if a little sad. Goodbye, baby blues.