Developmental Milestones and How They Impact Your Baby's Sleep

Updated Jun 9th 2022 | timer 4  min read

How Developmental Milestones can Impact Your Baby's Sleep
Mandy Treeby

Written By Mandy Treeby Chief Baby Sleep Consultant

While certain changes like growth spurts and teething lead to night waking, a true sleep regression is generally associated with physical and mental development. Let's look at some of the developmental milestones that may impact sleep and when you can expect them.


Getting the help and guidance you need to confidently manage these sleep setbacks is really important, Apps like the  Smart Sleep Coach by Pampers™ combine expert sleep coaching with tools to help you track your baby’s sleep so you can stay in the driver’s seat when sleep setbacks happen. It will help you see patterns emerge so you can celebrate as your baby re-adjusts back to their normal routine.

Changes in Sleep Patterns (usually around four months)

As your baby grows, changes start to occur in how she sleeps. Research shows that around four months old, babies begin to develop their circadian rhythm. Newborns spend most of their time in a deep sleep, but as the circadian rhythm develops, their sleep patterns start to look more like an adult. Older children and grown-ups cycle through different periods of light and heavy sleep throughout the night. During these phases of lighter, more wakeful sleep, your baby, who could once sleep through a marching band parading by, is more likely to be awakened by external factors, like light, noise and temperature.

The amount of sleep your baby needs will also change as she grows older. While newborns seem to sleep around the clock, as babies grow older, they experience longer periods of wakefulness and begin to form a regular  nap routine.

Rapid Developments and New Abilities (around six months)

By six months, you will begin to notice significant changes in your baby's development. It can seem like your baby is suddenly learning several new abilities at once. She will fine-tune her motor skills as she attempts to grab toys, put objects in her mouth, rollover, and sometimes even sit up when positioned. She is finding her voice and begins babbling and making new sounds. Her eyesight will improve, enhancing color recognition. These new abilities and stimuli are fascinating and can make it harder for your baby to fall asleep.

Emotional Development (around eight months)

In addition to gaining more physical abilities, like learning to crawl, by eight months, your baby is also beginning to understand object permanence or the idea that objects —and people continue to exist even when you can't see them. This new understanding can lead to some new emotions, particularly fear and anxiety. During this stage, your baby can experience separation anxiety and become more clingy and attached, leading to difficulty sleeping independently.

Increased Activity and Awareness (around 12 months)

By the time your baby reaches her first birthday, she is really moving! If she hasn't already taken those incredible first steps, she is working hard to master this pivotal developmental milestone. She can get frustrated that it's not happening fast enough, and she'll want to work towards her goal around the clock, even when she should be sleeping.

Your baby is also gearing up to say her first words, and she'll be experimenting even more with creating sounds. By this point, her eyesight has reached adult levels, which means she sees plenty of detail and is even more aware of changes to the world around her. This awareness can lead to clinginess, newfound fears and plain curiosity, making it harder to fall asleep.

Increased Independence (around 18 months)

By 18 months, your walking, talking toddler is developing a growing sense of independence. She wants to do more things on her own and is starting to test boundaries with her new favorite word, "No!" This increasing self-confidence is amazing as you watch your baby try new things and take more interest in grown-up activities, like helping put away groceries. However, it also means you'll likely be facing more battles at naptime and bedtime when she is more interested in her own agenda.

Read more about Stages of Sleep Regression by Age

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