Baby sleep regression by age: how long each one lasts and when it ends
If a week ago they were sleeping through the night and now they're waking up every hour, it's not that you did something wrong — it's probably a sleep regression. Here's what it actually is, which ages it tends to show up at, and how long each one lasts.
How long does a sleep regression last?
Most sleep regressions last between 2 and 6 weeks, depending on the age — the table below has the typical range for each one. They rarely end overnight: the nights get better gradually. If the rough patch goes on well beyond 6-8 weeks with no improvement at all, it may not be a regression, and it's worth mentioning to your pediatrician (see the FAQ below).
What a sleep regression actually is
A sleep regression is a stretch of several weeks where a baby who was sleeping relatively well suddenly starts waking up a lot more, taking longer to fall asleep, or fighting naps. It's not bad luck, and nothing's "broken" — it almost always lines up with a developmental leap: something new happening physically, cognitively, or emotionally that keeps their brain more active right when it should be winding down.
It's the same mechanism that triggers cortisol when a sleep window gets missed — except here it's not just one night, it's several weeks in a row while the brain processes the leap. That's why a regression doesn't "fix itself" overnight, and it isn't permanent either: it passes, even when it doesn't feel that way in the moment.
While it lasts, what helps most is staying with them, not letting them cry. If they fuss a little while settling back to sleep, you can reassure them with your voice and give them a moment to settle; if they cry, be by their side. Repeating the same routine every night, with you close by, is what gives them security until it passes.
Quick reference: sleep regressions by age
| Age | Typical duration |
|---|---|
| 4 months | 2 – 6 weeks |
| 8 – 10 months | 3 – 6 weeks |
| 12 months | 2 – 4 weeks |
| 18 months | 2 – 6 weeks |
| 2 years | Variable — weeks, sometimes longer |
These are general ranges, not a life sentence — some babies barely notice a given regression, and others carry it a bit past these weeks. Not every baby goes through every one: some clearly hit the 4-month regression and barely notice the 18-month one, or the other way around.
Regression month by month, with the cues for each one
This one's different from the others: it's not just "a rough patch," it's a real, permanent shift in how they sleep. Their sleep moves from a newborn pattern to one organized into cycles, with lighter stages in between — for the first time, something closer to adult sleep.
- Wakes up far more often than usual, especially between sleep cycles
- Struggles much more to fall back asleep once awake
- Naps get shorter overnight, sometimes down to 20-30 minutes
- More general irritability, especially by the end of the day
What changes here isn't "temporary" — the new sleep pattern is here to stay. What is temporary is how hard the adjustment feels while they get used to it.
This lines up with crawling, pulling up to stand, and the first strong wave of separation anxiety — suddenly it's much harder for them when you leave the room.
- Wakes up crying and reaching for you, not just making noise
- Actively protests when you leave the room
- Practices pulling up or crawling in the middle of the night, half asleep
- Daytime naps take a hit too, not just nighttime sleep
It's common for them to want to practice the new skill (pulling up to stand, especially) in the crib in the middle of the night, even exhausted — the body insists on drilling whatever it just learned.
Less universal than the others — not every baby notices this one — but it tends to line up with starting to walk and with the transition from 2 naps to 1.
- Fights the morning nap, even though they still need it
- More energy right before sleep, harder to "switch off"
- Wakes up earlier than usual in the morning
If it lines up exactly with the switch to one nap, it's worth not making both changes at once — let one settle before pushing the other.
Here another wave of separation anxiety collides with teething and a brand-new sense of independence — "I don't want to sleep" starts being a real sentence, not just a cry.
- Actual tantrums at bedtime, not just protest
- Actively asks you to stay, or calls out the moment you leave
- Wakes at night calling for you, not just crying
The independence piece is new compared to earlier regressions: it's no longer just that sleep is hard for them, it's that they're starting to decide they don't want to.
The most different one of all: this is when real nighttime fears and first true nightmares show up, along with a new ability to negotiate they didn't have before.
- Asks for "one more" before bed — book, water, a hug
- Starts putting words to being afraid of the dark or of being alone
- If they've already moved from crib to bed, they'll get up on their own and come find you in the middle of the night
It looks less like a pure sleep problem and more like something emotional — worth treating it that way, not just as a scheduling issue.
How to tell a regression is ending
Regressions rarely stop overnight. The usual signs are gradual: wake-ups become less frequent, falling back asleep takes less time, naps start to lengthen again, and the bad nights get mixed in with better ones. A single good night in the middle of a rough stretch doesn't mean it's over, and a bad night after a few good ones doesn't mean it's back — look at the pattern over a week, not at one night.
If the bad nights come in short bursts around a new tooth, or come with fever or other signs of illness, it may not be a regression at all: see teething and baby sleep. And if naps are the main problem, short naps have their own causes.
What about the 6-8 week and 6-month "regressions"?
You'll often see a "6-week," "8-week," or "6-month" regression mentioned online. These are far less consistent than the four above, and many babies don't have a clear one. Around 6-8 weeks, sleep is still very immature, and changes can come from growth spurts or the first signs of a day-night rhythm (see newborn day-night confusion); around 6 months, new skills like rolling over or sitting up and shifting nap needs can all play a part. They tend to be shorter and milder, and the same idea applies: keep the routine, stay close, and look at the pattern over a week.
This is the what and the when — not the how to fix it
Knowing it's a regression (and not that you've done something wrong as parents) already takes a lot of the weight off. But for the exact steps that help shorten it, tailored to your baby's age, sleep setup, and pace, the full guide has you covered.
See my personalized guideFrequently asked questions
How long does a sleep regression last?
Most sleep regressions last between 2 and 6 weeks, depending on the age: about 2-6 weeks at 4 months, 3-6 weeks at 8-10 months, 2-4 weeks at 12 months, and 2-6 weeks at 18 months. If the rough patch goes on beyond 6-8 weeks with no improvement, it's worth talking to your pediatrician.
How do I know when a sleep regression is ending?
The signs are usually gradual: wake-ups become less frequent, falling back asleep takes less time, naps start to lengthen again, and good nights begin to mix in with the bad ones. Look at the pattern over a week rather than a single night.
Is there an 8-week sleep regression?
Many parents report a rough patch around 6-8 weeks, but it's much less consistent than the 4, 8-10, 12, and 18-month regressions. At that age sleep is still very immature, and changes can come from growth spurts or the first signs of a day-night rhythm. It tends to be shorter and milder.
Is a sleep regression the same as a bad habit I need to correct?
No. A regression is temporary and tied to your baby's development, not to anything you've done wrong. There's no need to start over with sleep habits — though it can be a good moment to reinforce them once it passes.
Can I make the regression worse depending on how I react?
The regression itself isn't something you cause or avoid by doing "everything right" — it's development. What can happen is that a new sleep prop you introduce during those weeks (like rocking them all night) creates an association that outlasts the regression itself.
What if it lasts a lot longer than the typical weeks?
If it goes on for more than 6-8 weeks with no improvement at all, it's worth mentioning to your pediatrician to rule out medical causes (reflux, sleep apnea, ear infections) — not every extended stretch of night waking is a developmental regression.