Parents often wonder how to tell whether their baby is doing OK and growing as expected. Babies are quick to let you know when they’re uncomfortable, but it’s harder to tell if they are developing on track. Most month-by-month newborn development guides are written for full-term babies without medically complex conditions. But if your baby is in the neonatal intensive care unit (NICU) with a complex condition or was born prematurely, their developmental timeline may look a little different — and that’s OK.

Every baby develops at their own pace. Preemies and babies with complex medical or surgical conditions often need support to learn certain skills, but most will get there with a little more time. If your baby is growing, healing and making steady progress, that’s a great sign that they’re doing well.

Because it’s reassuring to know what progress can look like, our neonatal experts created a NICU developmental timeline for premature and medically complex babies. This timeline focuses on the first few weeks of life, when changes can happen quickly.

Here are a few things to keep in mind as you look at NICU milestones:

• Every baby develops differently, especially those in high-level NICUs.
• Some conditions impact specific areas of development, making certain skills harder — but babies are resilient and often adapt better than expected.
• While full-term development guides are broken into months, premature babies often change week by week, making short-term progress just as meaningful.

Premature baby milestones at 22 to 32 weeks' gestation

Babies born very prematurely often need significant medical support and long stretches of rest. In these early weeks, the most important milestones are not about activity, but about healing and growth. Your baby may spend most of their time sleeping, receiving care from the NICU team and slowly regaining strength.

What should you expect from your baby?

Very premature babies are often highly sensitive to their environment. Bright lights, loud sounds or too much handling can easily overwhelm them. Signs of overstimulation may include jittery movements, irritability, hiccups or frequent yawning. You’ll also notice that your baby needs long, uninterrupted periods of rest to heal and grow.

How can you support your baby in the NICU?

The best way to help your premature baby develop during this stage is by creating a calm, healing environment. Limit noise and bright light whenever possible, and spend time observing your baby to learn their unique mannerisms and stress cues.

In partnership with your NICU care team, you can provide comforting and developmentally supportive care, through strategies such as:

• Skin-to-skin contact (kangaroo care): Holding your baby against your chest helps regulate their temperature, breathing and heart rate.
• Containment: Gently cupping your baby’s head and feet at the same time can help them feel secure and calm.
• Scent bonding: Wearing a small piece of cloth against your skin and then placing it near your baby allows them to recognize your scent.
• Gentle interaction: Softly talk or sing to your baby, using a calm, soothing tone.
• Light management: Cover your baby’s eyes during necessary procedures and use the isolette cover to limit harsh lighting.
• Stress cue response: When you notice signs of overstimulation, try containment or soothing touch if your care team recommends it.
• Gentle care routines: A warm water sponge bath, based on the recommendations of your NICU team, can provide comfort.

Every premature baby is unique, and what works for one baby may not work for another. Ask your NICU care team what comfort strategies are appropriate for your baby. With your support, your baby can rest, heal and gradually build the strength they need for the next stage of development.

Premature baby milestones at 33 to 37 weeks' gestation

As your baby continues to grow stronger, you may notice small but meaningful changes. They may spend more time looking around when they are awake and show fewer signs of overstimulation compared to earlier weeks. Even so, your baby still needs plenty of rest and a calm environment to continue healing.

What should you expect from your baby?

During this stage, many premature babies begin to give clearer cues about their needs. While long stretches of rest are still typical, you may see early signs of feeding readiness. These include waking up before or during feeding times, sucking on a pacifier or showing the rooting reflex — when your baby opens their mouth and turns their head after their cheek or lips are touched. These behaviors are small steps toward breast or bottle feeding and are important developmental milestones in the NICU.

How can you help support your baby in the NICU?

As your baby adjusts to their surroundings, you can become more involved in their daily care. Spend time observing your baby to learn their stress cues. Parents can use the same comfort strategies as they would with full-term babies, just with some slight differences.

Premature baby milestones at 37 to 42 weeks’ gestation

By the time your baby reaches the age when most babies are born full-term, you may start noticing common newborn behaviors. They might start to be more alert, spend more time awake and begin exploring their surroundings. Still, it’s important to remember that your baby may not act exactly like a full-term newborn — and that’s OK. Focus on the incredible progress your baby has made and celebrate each step forward.

What should you expect from your baby?

At this stage, your baby will likely interact more with their environment. You may notice them trying to touch or grab items within reach. They may also spend longer times awake and respond more to the world around them. These milestones are an encouraging sign that your baby is building awareness and strength.

How can you help your baby?

By now, you might have gotten used to your baby’s personality and unique stress cues. Since your baby can handle more stimulation than before, you can begin to introduce new bonding strategies, with guidance from your NICU care team.

You might offer your baby safe objects to touch, such as soft blankets or grasping rings. Many babies enjoy looking at simple visuals like mirrors, black and white patterns, moving toys or pictures of faces. Allowing your baby supervised time unswaddled can also give them the chance to move freely. With each interaction, you’re not only helping your baby explore their world, but also strengthening the bond you share.

Premature baby milestones at 42 weeks to 3 months

For many families, this stage is when your baby might be ready to leave the NICU and head home, depending on their specific medical condition and progress. Typically, to go home, your baby must be feeding entirely by mouth or with the support of a nasogastric (NG) or gastrostomy tube (GT), steadily gaining weight, and on respiratory support that is suitable for home, most commonly low flow nasal cannula (LFNC).

If your baby meets these milestones, they may begin following a developmental timeline that looks more like that of a full-term baby. Still, every baby’s progress depends on their individual condition, so it’s important to talk with your care team about milestones and expectations.

What should you expect from your baby?

As your baby becomes stronger, you can expect them to be more alert during the day and sleep more consistently at night. They’ll continue interacting with you and with their environment. Around this time, babies may also begin reaching for and grabbing toys, and some may start rolling over or even attempting to sit — especially closer to the 3-month mark. These signs show that your baby is gaining strength and learning new skills.

How can you help support your baby in the NICU?

Once your baby is nearing discharge from the NICU, you’ll likely know their cues and personality well. Your role becomes even more important as you help them play, explore and meet new developmental milestones.

Introduce toys with new textures, shapes and sounds — always with supervision — to encourage sensory development. Help your baby practice reaching for and grabbing by placing objects within their sight and reach. Talking, reading or singing to your baby can help with bonding and early language development. You can also work with your care team to help establish healthy daytime and nighttime routines. At home, always make sure your baby  

By watching for changes in behavior, staying engaged and communicating with your care team, you’ll give your baby the best support as they transition out of the NICU and continue their development at home.

Rethinking milestones: Progress, not pressure

It’s completely OK to view developmental milestones as goals you and your baby need to achieve. But milestones should never be a source of guilt or pressure — especially for those who have babies who were born prematurely or have complex medical conditions.

Think of milestones as tools for you and your care team. They’re just one way to track your baby’s progress and identify areas where they may need some extra support.

Many factors determine when a baby reaches certain milestones, and it’s completely normal for one baby to learn a new skill before or after another. The most important thing for you to do is to take a broad look at your baby’s growth and progress throughout their NICU stay.