By Angelica Videla — Certified Baby and Toddler Sleep Consultant, London | Supporting families across the UK, Europe, US, and Australia
Quick Answer
The 12 month sleep regression hits alongside a surge in motor and language development and often coincides with the transition from 2 naps to 1. It typically lasts 2 to 6 weeks — but nap timing needs careful management during this period to avoid making sleep significantly worse.
What is the 12 month sleep regression?
Around 12 months your baby is hitting multiple milestones at once — walking, climbing, beginning to talk, and understanding far more of what is said to them than they can express. This neurological activity does not stop when the lights go out.
The 12 month regression is also closely tied to the nap transition. Around this age many babies begin showing signs of nap resistance — fighting one of the two naps, taking longer to fall asleep at bedtime, or waking earlier in the morning. This leads many parents to drop to one nap — sometimes too early, which significantly worsens sleep.
The key at 12 months is distinguishing between a true regression, a nap transition, or a schedule problem. They can look identical but the fix is different for each.
Signs your baby is going through the 12 month regression
- Suddenly waking at night after sleeping well
- Fighting naps — taking much longer to settle or refusing one nap
- Waking earlier in the morning than usual
- Increased clinginess and separation anxiety
- More difficulty settling at bedtime
- Appearing overtired but resisting sleep
How long does the 12 month sleep regression last?
The developmental component of the 12 month regression typically resolves within 2 to 6 weeks.
However, two things can extend it significantly. First, dropping to one nap too early. If your baby drops to one nap before they are genuinely ready — which for most babies is between 13 and 18 months — they become chronically overtired, which disrupts night sleep and early morning wakings for weeks or months.
Second, sleep associations that strengthen during the regression. If the regression period involves weeks of extra feeding, rocking, or co-sleeping responses to night waking, those patterns often need a gentle reset once the developmental leap passes.
What makes the 12 month regression worse
Dropping to one nap too early. This is the most common mistake at this age and the one that causes the most prolonged sleep disruption. Signs your baby is genuinely ready to drop to one nap include: consistently refusing one nap for at least 2 weeks, not showing overtiredness on one-nap days, and being at least 13 months old. A regression is not a sign of readiness to drop a nap.
Inconsistent schedule. At 12 months your baby's internal clock is well established. Significant day-to-day variation in nap and bedtime timing disrupts circadian rhythm and worsens night waking.
Too much or too little daytime sleep. At 12 months most babies need 2 to 3 hours of daytime sleep. Too much pushes bedtime later and causes early morning waking. Too little causes overtiredness and fragmented night sleep.
How to handle the 12 month sleep regression
1. Hold the 2-nap schedule if your baby is under 13 months
Unless your baby has been genuinely refusing one nap consistently for at least 2 weeks, keep the 2-nap schedule during the regression. A temporary nap fight during a regression is not the same as being ready to transition. See our 12-month sleep schedule for timing guidance.
2. Adjust wake windows slightly
At 12 months wake windows are around 3 to 4 hours. If your baby is fighting naps, try extending the morning wake window by 15 to 20 minutes before shortening nap timing.
3. Keep bedtime early
During a regression, earlier is almost always better. A bedtime between 6:30 and 7:30pm protects against the overtiredness that makes everything worse. Later bedtimes rarely result in later mornings at this age.
4. Maintain a consistent bedtime routine
A predictable 20 to 30 minute routine — bath, milk, books, song, sleep — gives your baby clear signals that sleep is coming and reduces the cortisol spike that makes settling harder.
5. Do not introduce new sleep associations
The temptation during a regression is to do whatever works to get everyone back to sleep. But feeding or rocking to sleep repeatedly during a regression almost always means those habits need to be undone afterwards. A consistent, intentional response is worth the short-term difficulty.
6. Get support if you need it
The 12 month regression combined with the nap transition is one of the most confusing periods in baby sleep. If you are unsure whether to drop a nap, what schedule to use, or how to address night waking, a personalised sleep plan can give you a clear path forward.
Frequently Asked Questions
How long does the 12 month sleep regression last?
The developmental component typically resolves within 2 to 6 weeks. Sleep disruption that continues beyond 6 weeks is usually driven by schedule issues or sleep associations rather than the regression itself.
Should I drop to one nap during the 12 month regression?
Not unless your baby has been clearly refusing one nap consistently for at least 2 weeks and is not overtired on one-nap days. For most babies the 2-to-1 nap transition happens between 13 and 18 months. Dropping too early during a regression is the most common cause of prolonged sleep disruption at this age.
Why is my 12 month old suddenly waking at night?
The most likely causes are the developmental regression, a schedule that needs adjusting, or sleep associations that have strengthened. Check wake windows, ensure bedtime is early enough, and consider whether your baby can fall asleep independently at the start of the night.
Is it normal for a 12 month old to wake multiple times at night?
Some night waking is normal at 12 months, but waking more than once or twice and needing help to resettle usually indicates a sleep association or schedule issue rather than a developmental norm.
My baby slept through and now wakes every night — will it go back to normal?
It may — once the developmental leap passes. But if your baby needs help to resettle each time they wake, that pattern is unlikely to resolve on its own without some adjustment to how they fall asleep initially.
How this might look in real life
At twelve months, sleep can change in a very noticeable way.
- Baby is suddenly refusing the second nap of the day
- Bedtime takes longer because baby is more active and alert
- Night wakings have returned after months of sleeping through
- Baby seems ready for one nap but crashes by early afternoon
- Walking and new skills are affecting how easily baby settles