Baby Sleep Regression Ages: The Complete Guide
4 months, 8 months, 12 months, 18 months... Why won't your baby sleep anymore? We break down every sleep regression, what causes them, and how to survive.
Sleep Regression Quick Reference
| Age | Duration | Main Cause |
|---|---|---|
| 4 months | 2-6 weeks | Sleep cycle maturation (permanent) |
| 6 months | 1-2 weeks | Growth spurt, sitting |
| 8-10 months | 3-6 weeks | Crawling, separation anxiety peak |
| 12 months | 2-4 weeks | Walking, nap transition |
| 18 months | 2-6 weeks | Independence, language, molars |
| 24 months | 2-4 weeks | Imagination, fears, toddler independence |
Every Sleep Regression Explained
What Causes It
- Permanent change in sleep architecture (cycles shift from 2 to 4-5 stages like adults)
- Baby now cycles between light and deep sleep every 45-60 minutes
- Increased awareness of surroundings
- Many babies learning to roll over around this time
Signs to Look For
- Waking every 1-2 hours at night (was sleeping longer stretches)
- Difficulty falling asleep at bedtime
- Short naps (30-45 minutes) that won't lengthen
- Fussier than usual, especially around sleep times
- More night feeds (even if previously dropped them)
How to Survive This Regression
- 1This is the only regression that represents a permanent change - sleep will not 'go back' to newborn patterns
- 2Focus on teaching baby to fall asleep independently if they haven't yet
- 3Ensure sleep environment is very dark and use white noise
- 4Watch wake windows carefully (around 1.5-2 hours at this age)
- 5This is often when parents consider sleep training
- 6Swaddle transition often happens here too - consider a sleep sack
Universal Sleep Regression Survival Tips
Stick to your routine
Consistent bedtime routines provide comfort and predictability during chaotic phases.
Watch wake windows
Overtired babies sleep worse. Adjust wake windows as your baby grows.
Don't start new habits you don't want to keep
If you bring baby to bed every night, it may become the new expectation.
Tag team with your partner
Take turns with night wakings to prevent burnout. Sleep deprivation is real.
Dark room + white noise
Optimize the sleep environment. These help with all ages and stages.
It will pass
Every regression ends. You will sleep again. This is temporary!
Frequently Asked Questions
Related Sleep Guides
Create Your Baby's Sleep Schedule
Use our free Sleep Schedule Calculator to get age-appropriate wake windows and nap times.
Open Sleep Calculator→Nap Window
Know exactly when your baby should nap, in seconds.
No tracking. No logging. No accounts. Ages 0–36 months.
Download on the App StoreFrom the makers of ParentCalc
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