Major Milestones in Your Baby’s First Year, Part 1: Newborn to 5 Months

Your baby’s first year is a period of remarkable change. Over these 12 months, you’ll witness them transform from a tiny bundle into a walking, talking, and interactive little person. In this first of a two-part series, Stanford Medicine Children’s Health pediatrician Amina Ahmed, MD, sheds some light on the significant milestones you should expect during your baby’s first year.  

Newborn to 2 months

In the earliest days of life, babies are busy adjusting to the world outside the womb. At this stage, they begin to strengthen their senses, refine reflexes, and connect with caregivers.

“For newborns, we’re looking at their muscle tone, we’re looking to see if the baby calms down when you’re holding and shushing them, and response to your touch,” Dr. Ahmed said. “It’s very, very normal in the first month for the babies to be sleeping most of the time.”

Around 1 month, your baby should start to be more wakeful, alert, and begin focusing on faces. “They are starting to get a sense of the world around them. At 1 month, they should be looking at your face when you are nursing them or talking to them,” she said. “They’re a little bit more alert after feeds and maybe just looking around.” At this age, babies may also start to smile, but it’s random and not necessarily a response.

By 2 months of age, babies will be able to track you from side to side and mimic you when you smile at them. 

“If you’re smiling, they may mimic that and smile back,” Dr. Ahmed said. “There’s a lot of what we call the mirror neurons acting out, and they’ll kind of mimic what you’re doing.”

At 2 months, babies will start orienting to sound. “If there’s a loud sound, they turn around. They can acknowledge that this is where the sound is coming from, or they respond to it,” Dr. Ahmed said. “If your baby is sleeping through you drumming on the table or something, that’s really concerning, and you should bring that up to your pediatrician.”

When giving your baby tummy time or letting them play unswaddled, you should start to see the baby trying to lift their head and moving their arms and legs more. “Their necks are not very strong yet, but they are lifting their head up a little bit,” she said. “They’re also moving all their limbs. It’s not just one arm; if that is happening, that’s always a concern.” Dr. Ahmed also mentioned that you’ll notice the baby’s body is starting to relax from the curled-up fetal position and the baby is opening their hands to grab and make fists.

3 to 5 months

Between 3 and 4 months of age, there’s a big jump in the maturity of your baby’s nervous system. You’ll see that reflecting in the baby’s development as they start giggling, smiling, and talking back with you and cooing. “During this time, it is really important to talk to your baby, sing to your baby, play with your baby; they will thoroughly enjoy it,” she explained. “You might hear the highs and the lows in their laughs and in their squealing. And that’s what we look for.”

They will also begin to track you throughout the room. So, if you walk into the room, they’ll orient to the sound track you as you’re walking.

At the same time, babies start getting a sense of their own body. “You’ll see them looking at their hands, and it’s almost like they are thinking, ‘Where did this thing come from?’ And then they start making the connection, oh, this is my own hand,” Dr. Ahmed said. “And then they’ll start bringing it to their mouth. And once they bring it into their mouth, it’s just this amazing sensation they’re getting in their brain, right? So, now they can not only feel their mouth with their hand, but they can also feel their hand with their mouth. So, there’s lots of sensations that they’re getting.”

Another big physical milestone is that babies will be able to hold their head up more and may even start rolling around at 4 months. As they get closer to 5 and 6 months old, they will start using their arms to push themselves up a bit when you put them on their belly.

Around this time, your baby will become much more aware of their surroundings. “They’ll be looking at the artwork on the wall. They’ll be interested in what they’re seeing. If you have a little something hanging over their crib, they will watch it move. They’ll enjoy looking at the patterns on the wall, fans, etc.,” she said.

Each month, your baby is building the foundation for future skills. However, it’s important to remember that every baby’s journey is unique.

“Every baby goes at their own pace. I cannot emphasize enough that people should try to make it to their well check appointments because that’s when your pediatrician is evaluating for different milestones,” Dr. Ahmed said. “I want parents to know in the back of their mind that there are going to be some babies who will not meet these milestones at the same time. Talk to your pediatrician. No matter if it’s a delay or they just need a little bit more encouragement, your doctor can counsel you on how you can support your baby’s development.”

Learn more about your baby’s milestones from 6 to 12 months in part 2 coming next month.

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