The 12 month shift is a real one. Your baby is on the edge of toddlerhood, and their sleep is changing along with everything else.
If your baby has just turned one and their sleep has suddenly become unpredictable, you're not imagining it. Around 12 months, many babies go through a clear shift in how they sleep, what they need at bedtime, and how they move through their days. It can feel like a regression, but really, it's a transition into a whole new stage of childhood.
Let me walk you through what's behind this shift, when to expect things to settle, and how to support your baby gently through it.
What's happening at 12 months
A lot is changing all at once. Your baby is likely walking or close to it, which is one of the biggest physical and cognitive milestones of the early years. Their language is starting to take off. Their personality is showing up in clearer ways. They're noticing the world with more depth and asking for more from it. All of that growth is exhausting, exhilarating, and disruptive to sleep.
At the same time, sleep itself is changing. Their daytime sleep needs are shifting (some babies are getting close to dropping a nap, others are still firmly on two). Their wake windows are stretching. Their bedtime might be drifting later. Their nighttime sleep often becomes lighter for a stretch as their brain integrates all the new skills.
How babies move through sleep continues to mature too. Around 12 months, the boundary between deep sleep and lighter sleep continues to develop, which can mean more brief wakings or harder resettling for a few weeks.
Why this shift is real
The 12 month shift gets less attention than the 4 month one, but it's just as significant for many families. The combination of physical milestones, cognitive growth, and changing sleep needs creates the conditions for a temporary unsettling. The good news is that it's almost always temporary, and by the time it eases, your toddler often emerges with more settled sleep on the other side.
Some signs of the shift include sudden bedtime resistance, more night waking, shorter naps, longer wake windows, frequent calls for you in the night, and a general sense that the routine you'd built is no longer fitting.
What helps
Start by checking your baby's daytime sleep needs. Around 12 months, many babies need a longer wake window between the morning nap and the afternoon nap, or between the afternoon nap and bedtime. If sleep needs have shifted but the schedule hasn't, you may be putting them down too early, which leads to short naps and more night wakings.
Nap dropping happens sometime between 13 and 18 months for most babies, but the lead in to that drop can begin at 12 months with shorter or skipped morning naps. If you're seeing signs of that transition, it's okay to start playing with the timing.
A calm bedtime rhythm becomes even more anchoring at this age. Predictability is your friend. The same flow each night helps your baby's body recognise that it's time to wind down, even when the rest of the day has been full of new things.
Lean into extra closeness through this shift. Your baby is on the edge of being a toddler, but they're still very much a baby in many ways. Extra cuddles, longer bedtime stories, slower transitions all help them settle into the new stage feeling held.
Try not to make big sleep changes during this period. If you've been thinking about moving rooms, dropping a feed, or transitioning to a new sleep setup, consider waiting a few weeks until the shift has settled. New skills often need to integrate before adding more change.
If you'd love a deep, gentle understanding of what's happening in your baby's brain through every stage, the Your Baby's Brain guide walks you through it. It includes what's happening developmentally at each age, how it affects sleep, and how responsive caregiving builds the brain connections that support better long term sleep. It's a deeply reassuring resource for moving through shifts like this.
The 12 month shift is real, and it's also temporary. Your baby is growing in ways that are nothing short of amazing, and you're growing right alongside them.
