- When: usually somewhere between 8 and 10 months (corrected age for babies born early). Some call it the 9 month or 10 month sleep regression; it's the same stretch.
- Why: crawling, pulling up to stand and separation anxiety tend to arrive together, and small studies show new motor skills go with more broken sleep for a while.
- How long: often 2–6 weeks, sometimes in two waves, crawling first and standing later.
- What helps most: lots of practice by day, including sitting back down from standing, and the same short goodbye every night.
When does the 8, 9 or 10 month sleep regression start?
There's no single date. This one follows skills, not the calendar, and babies reach those skills at different times. For many it shows up around 8 months, with the first real crawling; for others closer to 9 or 10 months, when pulling up to stand arrives. That's why you'll see it called the 8 month, the 9 month or the 10 month sleep regression: parents are describing the same thing at slightly different moments.
For a baby born more than 3 weeks early, count from the due date. A baby born 6 weeks early who is 9 months old is developmentally closer to 7½ months, and may hit this stretch later. The calendar above does the math: enter the birth date and, if needed, the due date, and it shows whether the 8–10 month window is behind you, happening now or still ahead.
What's really going on
Two things come together at this age: big new movements and a new awareness that you exist even when you're out of sight.
New moves, practiced at night
A baby who has just learned to crawl or stand wants to do it, and the crib is where they wake up between sleep cycles. Several small studies that measured sleep at home with movement sensors found the same pattern: a new motor skill goes with a stretch of more broken sleep, and then things settle.
| Milestone | What the study found | Study |
|---|---|---|
| Crawling | 8-month-olds who had started crawling had more fragmented sleep than babies the same age who hadn't yet | Scher 2005, 59 babies |
| Pulling up to stand | in babies who pulled to stand early (by 8 months), the new skill was linked in time to a period of disrupted sleep | Atun-Einy and Scher 2016, 20 babies followed from 7 to 12 months |
| Walking (usually later) | learning a new motor skill brought temporary increases in night waking and movement at night | DeMasi et al. 2023, 78 babies |
The word that matters in all three is temporary. None of these studies found lasting damage to sleep; they found a bumpy patch while the skill was new.
Separation anxiety
Around the same age, babies start to understand that you can leave, and they don't like it. The CDC's milestones for 9 months include being shy, clingy or fearful around strangers and reacting when you leave: looking for you, reaching for you or crying. The AAP says separation anxiety usually peaks between 10 and 18 months and fades in the second half of the second year, and that a baby may wake up searching for you in the middle of the night. Bedtime, when you walk out of the room, is the hardest goodbye of the day.
Signs of the 8–10 month sleep regression
- Standing up in the crib and crying, because they can get up but don't yet know how to get back down.
- Crawling, rolling or rocking on hands and knees instead of settling.
- Clinging at bedtime and crying the moment you head for the door.
- Waking at night and calling for you after weeks of sleeping well.
- Shorter naps and earlier mornings.
If the waking comes with a fever, ear pulling during a cold, vomiting, poor feeding or fewer wet diapers, that points to illness rather than a regression; call your pediatrician.
How long does the 8–10 month sleep regression last?
Often 2 to 6 weeks, though nobody has measured this precisely. It sometimes comes in two waves: a few rough weeks around crawling, a calmer stretch, then another round when pulling up and standing arrive. Once a skill stops being new, it stops being so exciting at 2 a.m. Separation anxiety runs on a longer clock, but it shows up more as bedtime protest than as hours awake.
What helps
- Floor time, lots of it. Let your baby crawl, pull up and cruise as much as possible during the day, so the new skill is old news by bedtime.
- Practice sitting back down. Standing is easy; getting down is the hard part. During play, help them bend their knees and lower themselves from the couch or a low table. A baby who can sit down alone doesn't need you every time they stand in the crib.
- The same short goodbye. A predictable bedtime routine and the same few words when you leave make the separation less of a surprise. In a study of 405 families, a simple nightly routine cut night waking and shortened the time to fall asleep within two weeks.
- Brief, calm check-ins. If they cry, go in, lay them back down, say the same words, and leave. Quick and boring tells them you're near without turning the night into playtime.
- Keep two naps. Most babies this age still need two. An overtired baby has a harder time settling; on rough days an earlier bedtime helps.
- Same safe sleep. On the back to start, in an empty crib on a firm, flat mattress. A baby who now stands can climb on anything you leave in there.
What's next
After this stretch, many babies sleep well until around the first birthday, when walking and the first nap strike arrive: see the 12 month sleep regression. If naps are part of the trouble, the nap planner shows wake windows by age and suggests when to put your baby down for two naps a day.
Frequently asked questions
Is it the 8, 9 or 10 month sleep regression?
All three names describe the same stretch. It follows new skills, crawling and pulling up to stand, plus separation anxiety, so it lands whenever your baby reaches them, usually somewhere between 8 and 10 months (corrected age if born early).
Why does my baby stand in the crib and cry?
Most likely because they can pull up but can't yet get back down. They practice the new skill when they wake between sleep cycles, then get stuck. Practicing sitting down from standing during the day usually solves it within a few weeks.
Can separation anxiety cause night waking at 9 months?
Yes. The AAP notes that separation anxiety can mean a baby wakes searching for you in the middle of the night, and it usually peaks between 10 and 18 months. A predictable routine, the same short goodbye and calm, brief check-ins help.
How long does the 9 month sleep regression last?
Often 2 to 6 weeks, sometimes in two waves as crawling and then standing arrive. Studies of new motor skills found the sleep disruption was temporary.
Should I drop to one nap at 9 or 10 months?
Usually not. Most babies this age still need two naps, and refusing a nap for a few days during a regression isn't a sign to drop it. An earlier bedtime covers the rough days.
Is my 10 month old teething or is it a regression?
Teething symptoms cluster in a few days around each tooth; a stretch of several weeks is more likely the regression. If you see fever, ear pulling with a cold or poor feeding, call your pediatrician.
Sources
- Scher A., Crawling in and out of sleep, Infant Child Dev 2005: crawlers' sleep more fragmented than same-age pre-crawlers, 59 eight-month-olds
- Atun-Einy O., Scher A., Sleep disruption and motor development: does pulling-to-stand impact sleep–wake regulation? Infant Behav Dev 2016
- DeMasi A. et al., Infant motor development predicts the dynamics of movement during sleep, Infancy 2023
- HealthyChildren.org (AAP): Emotional and Social Development, 8 to 12 Months
- CDC: Milestones by 9 Months
- Mindell J.A. et al., A nightly bedtime routine: impact on sleep in young children and maternal mood, Sleep 2009
- Macknin M.L. et al., Symptoms associated with infant teething: a prospective study, Pediatrics 2000
- HealthyChildren.org (AAP): Corrected Age for Preemies
- Moon R.Y. et al., Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment, Pediatrics 2022
Spotted a mistake or an outdated figure? Write to [email protected].