Sleep Regressions in Babies and Toddlers: Ages, Signs, How Long They Last, and How to Help

What a regression is, when they happen, how long each one lasts, and the signs that disrupted sleep is not a regression at all.

Editorial content, aligned with the American Academy of Pediatrics safe-sleep guidance. Sources are cited in the text and listed at the foot of the page. · Last updated [date]

What is a sleep regression?

A sleep regression is a temporary period — usually a few weeks — when a baby or toddler who had been sleeping reasonably well starts waking more at night, fighting naps or bedtime, taking shorter naps, or waking earlier than usual. It typically shows up alongside a burst of developmental change: new movement skills, new awareness, a shift in sleep needs.

Two things worth knowing before anything else. First, "regression" isn't a clinical term. Sleep researchers describe infant sleep as consolidating over the first year — longer stretches, fewer wakings — with plenty of variation and plenty of backsliding along the way.²,⁸ What parents call a regression is usually one of those normal reversals, seen from inside a house where nobody is sleeping. Second, that framing is good news: a regression isn't something that has gone wrong, and it isn't something a parent caused. It's development showing up at night.

The goal, then, isn't to cure it. It's to keep sleep safe, keep the routine steady, and recognize the small number of situations where what looks like a regression is something else.

At what ages do sleep regressions happen?

Regressions cluster around predictable developmental windows. Timing varies by weeks either side, and some children skip some entirely.

The ages are not a schedule. A baby who crawls at seven months may have the "8–10 month" regression at seven. The trigger is the developmental change, not the calendar.

How long do sleep regressions last?

Most sleep regressions run two to six weeks. The 4-month adjustment is often on the shorter end; regressions tied to big motor or language leaps, or to a life change like a new sibling, can run to the longer end.

That two-to-six-week figure comes from pediatric sleep clinicians' experience, and it's consistent across children's hospitals and sleep practices.¹ It isn't a study result — no research has defined a "regression" and timed it — so use it as a rule of thumb. What the research does show is that night waking follows a bumpy path rather than a straight line: in a study following about 1,200 infants from 6 to 36 months, roughly two-thirds settled into consolidated night sleep by 6 months and stayed there, while about a third continued to wake regularly, with the biggest improvements happening between 6 and 15 months.⁴ Some backsliding along that path is the norm.

If it's been more than about eight weeks with no improvement, or sleep was never settled to begin with, that is not a regression. See "Is it a sleep regression, or something else?" below.

What makes a regression longer or shorter?

Five things, in roughly the order they matter.

What happens at each waking. A regression stretches when every night waking is met with a new way of getting back to sleep — rocking one night, feeding the next, the parents' bed the next. Each of those becomes something the child then needs. Responding the same way each time, whatever that way is, is what lets the regression end when the developmental trigger passes.⁹

The bedtime routine. A consistent wind-down is the best-supported single practice in infant sleep. In a study of more than 10,000 mothers across 14 countries, children with a regular bedtime routine fell asleep faster, woke less, and slept longer — and the more nights a week the routine was done, the bigger the effect.⁵

Progress on the milestone. A baby who gets to practice crawling or standing all day is less likely to practice it at 2 a.m.

What else is going on. Teething, a cold, travel, a clock change, a new sibling, a new bed. Regressions that coincide with two of these run long.

Sleep needs shifting under the schedule. A child who has outgrown a nap, or a bedtime that's now too early, will resist sleep in a way that looks like a regression and is really a schedule that needs adjusting. The sleep-needs section below has the ranges.

What are the signs of a sleep regression?

The signs are ordinary sleep behavior arriving suddenly in a child who wasn't doing it:

• Fighting naps or bedtime that used to go smoothly
• More frequent night wakings, often at the same points in the night
• Difficulty settling even when clearly tired
• Shorter naps, or naps that end abruptly at 30–45 minutes
• Waking earlier in the morning
• More crying, clinginess, or fussing around the bedtime routine
• Practicing a new skill in the crib — rolling, sitting, standing, talking — instead of sleeping

Two patterns get their own names. A nap strike is a stretch of refusing naps entirely despite clear tiredness, common around 12 and 18 months as nap needs shift. Bedtime stalling is the toddler version: one more book, one more drink, one more question, as the child's growing sense of autonomy meets a fixed bedtime.

What's not on this list: fever, ear-pulling, snoring, gasping, or a child who seems unwell. Those are covered in the section on what isn't a regression.

Why do sleep regressions happen?

Because sleep is a developmental skill, and it develops in jumps.

Sleep architecture matures. Newborn sleep is split roughly evenly between active (REM-like) and quiet sleep, with cycles of about 50 minutes and no strong day-night rhythm. Over the first months, sleep reorganizes into the adult-like pattern of distinct stages, longer cycles, and a circadian rhythm that puts the longest stretch at night.²,³ That reorganization is the engine behind the 4-month regression.

Motor milestones. Rolling, crawling, pulling to stand, cruising, walking. Each one arrives with a drive to practice it, and each changes what a baby can do in the crib. A baby who has just learned to stand will stand, and then may not know how to get back down.

Cognitive and social milestones. Object permanence — the understanding that a parent who has left the room still exists — arrives around 8 to 10 months and brings separation anxiety with it. Language bursts around 18 months and imagination around 2 years bring stalling, fears, and a mind that doesn't switch off on cue.

Sleep needs change. Total sleep falls across the first three years, and naps consolidate from several to two to one to none.⁸,¹⁰ A schedule that fit last month can produce bedtime resistance this month.

Everyday disruptors. Teething is blamed for more than it causes — in a prospective study that tracked 125 children daily through 475 tooth eruptions, teething was associated with mild symptoms including some sleep disturbance, but no symptom was consistent enough to reliably predict a tooth.¹¹ Illness, travel, a clock change, and a new sibling are more reliable disruptors than teeth.

The 4-month sleep regression: why it's different

Every other regression on this page is a temporary disruption that passes. The 4-month one is a permanent change that a baby has to learn to live with, which is why it deserves its own section and why "wait it out" is the wrong plan for it.

Around 3 to 4 months, a baby's sleep stops being newborn sleep. The cycles lengthen and separate into stages, including light stages in which a baby drifts close to waking at the end of each cycle.²,³ An adult passes through those moments without noticing. A baby who has always been fed, rocked, or held to sleep surfaces at the end of a cycle, finds the conditions different from the ones they fell asleep in, and calls for them to be restored. The result is a baby who was sleeping five-hour stretches at 10 weeks and is now waking every 90 minutes.

That's why the practical advice for this age differs from every other regression: the goal is to help the baby learn to fall asleep in the conditions they'll wake up in. The research on this is more solid than most of infant sleep — a systematic review of 52 studies found that behavioral approaches to bedtime and night waking (consistent routines, putting the baby down drowsy but awake, and graduated responses to waking) were effective for the large majority of infants and young children, with no evidence of harm.⁹ A randomized trial that followed families for two months found the same, with the added benefit of improved maternal mood.¹²

Two honest limits. Those approaches are studied from about six months; before then, the AAP's guidance is simply consistency and safe sleep, and a 4-month-old who still feeds at night is doing something normal. And "drowsy but awake" is a direction, not a rule — some babies take to it in a week, some take months, and the parent who can't do it every night is not failing.

What happens at 8, 12, 18 months and 2 years?

8 to 10 months. Two things arrive together: mobility (crawling, pulling to stand) and object permanence. The first means a baby can now stand up in the crib and may not be able to get down; the second means a parent leaving the room is now an event. Expect protest at bedtime, standing and crying, and waking that ends the moment a parent appears. Helps: lots of daytime practice getting down from standing; a short, predictable goodnight that's the same every time; brief, boring check-ins rather than a return to the old way of settling. See separation anxiety for the version that runs strong.

12 months. Walking, or the run-up to it, plus the start of the two-naps-to-one transition for some babies. The regression here is often a nap strike: the morning nap gets refused, the afternoon one gets pushed. Most children aren't ready for one nap until 14 to 18 months; forcing it at 12 produces an overtired evening. Helps: keep two naps but cap the morning one; move bedtime earlier on one-nap days.

18 months. Language, autonomy, and molars. The toddler who can now say "no" says it at bedtime. Helps: a routine with a fixed number of steps ("bath, two books, song, lights") that the child can predict and even lead; choices inside the routine (which pajamas, which book) rather than about it; the same response to every waking.

2 to 3 years. Imagination and fear arrive together, and so do big life changes — a bed, a sibling, potty training, preschool. Night fears are real to the child and don't respond to logic. Helps: a nightlight is fine (dim, warm; see night light color); a single comfort object; naming the fear and a short script for it ("the shadow is the chair; I'll check; you're safe"); keeping the crib until at least 3 unless the child is climbing out. Dropping the nap before the child is ready produces an early-evening collapse and a 5 a.m. wake-up.

How much sleep does my baby or toddler need?

Two sets of numbers are worth having side by side: what pediatric sleep medicine recommends, and what children actually do.

The range in the third column is the point. A systematic review of 34 studies found that "normal" sleep duration spans about six hours at any age — a 1-year-old sleeping 10 hours and one sleeping 14 are both within the observed range.⁸ If your child is at the low end, alert, and growing, they may simply need less sleep than the schedule assumes, and the "regression" may be a bedtime that's now too early.

Is my baby sleeping through the night "late"?

Probably not, and the phrase means less than it seems to.

In a study that followed 75 infants across the first year with parent sleep diaries, half were sleeping a five-hour stretch (midnight to 5 a.m.) by 3 months, and half were sleeping from 10 p.m. to 6 a.m. by 5 months — but the spread was wide, and the biggest predictor of sleeping through at 6 and 12 months was whether a parent was present when the baby fell asleep at 1 month.² In the larger study that followed infants to 36 months, about a third still woke regularly at night at 6 months, and a meaningful minority did at 3 years.⁴

More useful still: in a study of about 400 infants, whether a baby slept through the night at 6 or 12 months was not associated with their mental or motor development, and was not associated with maternal mood either — though it was, unsurprisingly, associated with breastfeeding.¹³ A baby who wakes at night at 9 months is not behind, and a parent who isn't sleep-training is not causing a problem.

How do I help my baby through a sleep regression?

The strategies with evidence behind them are few, and they're the boring ones.

Keep the routine, exactly. The same steps in the same order at the same time. The 14-country study found the benefit of a bedtime routine was dose-dependent: every additional night a week it was done, sleep improved.⁵ A regression is the time to hold the routine most tightly, not to abandon it.

Respond the same way to every waking. Whatever your approach — a hand on the back, a brief check, a feed if the baby is young enough to need one — do it the same way each time. The evidence for behavioral approaches is strongest when the response is consistent.⁹ The failure mode isn't picking the "wrong" method; it's changing methods nightly.

Drowsy but awake, where it works. Putting a baby down before they're fully asleep, so they fall asleep in the crib they'll wake up in, is the practice most consistently associated with self-settling.²,⁹ It's a direction to lean toward, not a test to pass.

Get the daytime right. Enough daylight and activity, plenty of practice for whatever new skill is keeping the baby up, and naps that match the child's current needs rather than last month's.

Adjust the schedule, gradually. If a nap is being refused day after day, the transition may be due — move it in 15-minute steps over a week or two rather than dropping it at once, and bring bedtime earlier on the days it goes badly.

About "wake windows." Charts of ideal awake time by age circulate everywhere. They're a practitioner convention, not a research finding, and the ranges vary by source. Use them as a starting point and let your child's tiredness cues — rubbing eyes, looking away, fussing — overrule the chart.

Protect your own sleep. Regressions are as hard on parents as on babies. Trading nights, napping when the baby naps, and asking for help are strategies, not weaknesses. The one intervention trial that measured it found maternal mood improved when infant sleep did.¹²

What's safe to try, and what isn't?

Every night, regression or not:

• Back to sleep, on a firm, flat surface, in the baby's own crib or bassinet, in the parents' room for at least the first six months. Nothing loose in the sleep space — no blankets, pillows, bumpers, or soft toys.⁶
• No weighted blankets, weighted swaddles, or weighted sleep sacks. The AAP's 2022 guidance advises against weighted products for infants, and the CPSC has warned that they are unsafe for sleep.⁶ DrParenting has a full page on weighted blankets and infants.
• Stop swaddling once a baby shows signs of rolling, which is usually around the same time as the 4-month regression.⁶
• A white noise machine is fine at a moderate volume, across the room, not next to the crib. See noise machines for babies.
• A nightlight is fine for a toddler with fears; dim and warm.

Not for babies and toddlers:

• Melatonin. Not for regressions, and not for any child without a clinician's involvement. The American Academy of Sleep Medicine's 2022 advisory cautions against using melatonin in children without medical guidance, and reports of pediatric melatonin overdoses have risen sharply.¹⁴
• Sedating antihistamines or any over-the-counter sleep aid.
• Essential oils, herbal teas, or supplements marketed for infant sleep.
• Positioners, inclined sleepers, or rockers for sleep. Not safe sleep surfaces.⁶
• Mouth taping, chin straps, or anything that restricts breathing or movement.

Sleep regressions in autistic and neurodivergent children

Sleep problems are far more common in autistic children than in the general population — clinical estimates run to half or more — and they tend to be longer-lasting and to respond less to the ordinary strategies.¹⁵ Children with ADHD and children with sensory processing differences also sleep worse on average. For these children a "regression" may not be a regression at all; it may be the visible edge of an ongoing pattern.

What helps is mostly the same as for any child, done more deliberately:

• Predictability above everything. A visual bedtime schedule, the same order every night, and advance warning of each step. Change one thing at a time.
• A low-input room. Dark, quiet, cool; blackout blinds; a white noise machine if the house is noisy; bedding and pajamas chosen by feel, with tags removed, for a child who is over-responsive to texture.
• Deep pressure before bed, awake and supervised. Firm hugs, being wrapped snugly in a blanket while awake, lying under sofa cushions. Deep pressure input has the strongest evidence of any sensory strategy in children¹⁶ — and none of it goes in the crib, and none of it means a weighted product for sleep.
• A movement outlet earlier in the day for a child who seeks input, so bedtime doesn't become the first chance to get it.
• A pediatrician's involvement. For autistic children, the AAP-endorsed practice pathway recommends screening for medical contributors to insomnia (reflux, constipation, sleep-disordered breathing, seizures) before anything else, then behavioral strategies, and only then, if needed, a discussion of melatonin under medical supervision.¹⁵

The DrSensory clinical side has a full page on sensory processing and sleep problems in autism, and an occupational therapist can build a bedtime plan around a child's specific profile. Find a pediatric occupational therapist.

Is it a sleep regression, or something else?

A regression is temporary, lines up with a developmental change, and improves within weeks. Anything that doesn't fit that shape deserves a different name and, often, a doctor.

Snoring and breathing pauses are the ones not to wait on. The AAP guideline on childhood obstructive sleep apnea recommends that every child be screened for snoring, and that a child who snores and has other signs be evaluated with a sleep study.⁷ In a population study of about 11,000 children, sleep-disordered breathing in infancy and toddlerhood predicted substantially higher odds of behavioral difficulties at ages 4 and 7 — even when the breathing symptoms had resolved.¹⁷ Nighttime mouth breathing and drooling are often the first signs; the nighttime drooling page covers what to look for.

Illness — ear infections, colds, reflux — is the most common non-regression cause of sudden bad sleep in babies, and it's the one parents most often mistake for a regression because the timing is a coincidence.

Does a sleep regression affect development?

A few weeks of disrupted sleep does not harm a child's development. The evidence for that is indirect but reassuring: infant sleep consolidation is so variable across the first three years that a large share of children who are developing normally spend months at a time waking at night,⁴ and in the study that looked directly, sleeping through the night at 6 or 12 months was not associated with developmental outcomes.¹³

What a stretch of poor sleep does do, temporarily, is what it does to anyone: a crankier, clingier child with a shorter fuse and less patience for learning something new. That resolves when sleep does. If it doesn't — if the behavior changes outlast the sleep disruption, or the sleep disruption never ends — that's the situation to raise with a pediatrician, and the section above on sleep-disordered breathing is the first thing to rule out.

The reverse question — whether development affects sleep — has a clear answer: yes, constantly. That's what a regression is.

When should I call the pediatrician?

Same-day or prompt call:

• Snoring most nights, gasping, or pauses in breathing during sleep
• Fever, ear-pulling, refusal to feed, vomiting, or a child who seems unwell
• A regression in skills — a child who has lost words, movement, or social engagement they had (this is a different kind of regression entirely and needs evaluation; see autism regression)

Next routine visit:

• Sleep disruption that has lasted more than about eight weeks with no improvement
• Daytime sleepiness, hyperactivity, or irritability that outlasts the bad nights
• A child who has never settled into a night sleep pattern by 12 months and it's affecting the family
• Autism, ADHD, or sensory differences are part of the picture and you want a plan built around them

Come with two weeks of notes: bedtime, wake times, night wakings, naps, and anything that coincided. A phone recording of a child's night breathing, if there's any snoring, is worth more than a description.

---

Frequently asked questions

Sources

1. Children's Health / UT Southwestern (Basora-Rovira E). Sleep regression in infants and toddlers. Clinician-authored guidance stating that regressions typically last two to six weeks. childrens.com. Checked September 3, 2026. Cited only for the two-to-six-week convention, which the text identifies as clinical experience rather than a study finding.
2. Henderson JMT, France KG, Owens JL, Blampied NM. Sleeping through the night: the consolidation of self-regulated sleep across the first year of life. Pediatrics. 2010;126(5):e1081–e1087. PMID 20974775. Seventy-five infants followed with parent diaries; 50% met the midnight-to-5 a.m. criterion by 3 months and the 10 p.m.-to-6 a.m. criterion by 5 months; parental presence at sleep onset at 1 month predicted sleep status at 6 and 12 months. doi:10.1542/peds.2010-0976
3. Henderson JMT, France KG, Blampied NM. The consolidation of infants' nocturnal sleep across the first year of life. Sleep Medicine Reviews. 2011;15(4):211–220. PMID 21051245. Review of sleep architecture maturation and the lengthening of sustained sleep across the first year. doi:10.1016/j.smrv.2010.08.003
4. Weinraub M, Bender RH, Friedman SL, et al. Patterns of developmental change in infants' nighttime sleep awakenings from 6 through 36 months of age. Developmental Psychology. 2012;48(6):1511–1528. PMID 22448981. doi:10.1037/a0027680. NICHD Study of Early Child Care cohort, about 1,200 infants; two trajectory groups — roughly two-thirds "sleepers" consolidated by 6 months and one-third "transitional sleepers" still waking, with the steepest improvement between 6 and 15 months.
5. Mindell JA, Li AM, Sadeh A, Kwon R, Goh DYT. Bedtime routines for young children: a dose-dependent association with sleep outcomes. Sleep. 2015;38(5):717–722. More than 10,000 mothers in 14 countries; a consistent bedtime routine was associated with earlier bedtimes, shorter sleep onset, fewer night wakings, and longer sleep, with a dose-dependent relationship to routine frequency. doi:10.5665/sleep.4662
6. Moon RY, Carlin RF, Hand I; AAP Task Force on Sudden Infant Death Syndrome. Sleep-related infant deaths: updated 2022 recommendations for reducing infant deaths in the sleep environment. Pediatrics. 2022;150(1):e2022057990. PMID 35726558. Back to sleep, firm flat surface, room-sharing without bed-sharing, nothing in the sleep space, no weighted products, stop swaddling at signs of rolling. doi:10.1542/peds.2022-057990. U.S. CPSC statement on weighted infant swaddles and blankets: cpsc.gov.
7. Marcus CL, Brooks LJ, Draper KA, et al.; American Academy of Pediatrics. Diagnosis and management of childhood obstructive sleep apnea syndrome. Pediatrics. 2012;130(3):576–584. PMID 22926173. All children should be screened for snoring; polysomnography for those with snoring plus other signs. doi:10.1542/peds.2012-1671
8. Galland BC, Taylor BJ, Elder DE, Herbison P. Normal sleep patterns in infants and children: a systematic review of observational studies. Sleep Medicine Reviews. 2012;16(3):213–222. Thirty-four studies; reference means and ±1.96 SD ranges for sleep duration — infant 12.8 h (9.7–15.9), toddler/preschool 11.9 h (9.9–13.8), child 9.2 h (7.6–10.8). doi:10.1016/j.smrv.2011.06.001
9. Mindell JA, Kuhn B, Lewin DS, Meltzer LJ, Sadeh A; American Academy of Sleep Medicine. Behavioral treatment of bedtime problems and night wakings in infants and young children. Sleep. 2006;29(10):1263–1276. PMID 17068979. Review of 52 treatment studies by an AASM task force. 94% of the studies reported that behavioral interventions were efficacious, and over 80% of the children treated showed clinically significant improvement maintained for three to six months. The abstract does not address adverse effects.
10. Paruthi S, Brooks LJ, D'Ambrosio C, et al. Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. Journal of Clinical Sleep Medicine. 2016;12(6):785–786. PMID 27250809. Infants 4–12 months 12–16 h; 1–2 years 11–14 h; 3–5 years 10–13 h, per 24 hours including naps. doi:10.5664/jcsm.5866
11. Macknin ML, Piedmonte M, Jacobs J, Skibinski C. Symptoms associated with infant teething: a prospective study. Pediatrics. 2000;105(4):747–752. PMID 10742315. One hundred twenty-five children followed daily; 475 tooth eruptions; teething associated with mild symptoms in the days around eruption, but no symptom was reliably predictive of a tooth. doi:10.1542/peds.105.4.747
12. Hiscock H, Wake M. Randomised controlled trial of behavioural infant sleep intervention to improve infant sleep and maternal mood. BMJ. 2002;324(7345):1062–1065. PMID 11991909. Behavioral intervention improved infant sleep problems and maternal depression scores at two months. doi:10.1136/bmj.324.7345.1062
13. Pennestri MH, Laganière C, Bouvette-Turcot AA, et al. Uninterrupted infant sleep, development, and maternal mood. Pediatrics. 2018;142(6):e20174330. PMID 30420470. Sleeping through the night at 6 and 12 months was not associated with mental or psychomotor development or maternal mood. doi:10.1542/peds.2017-4330
14. American Academy of Sleep Medicine. Health Advisory: Melatonin Use in Children and Adolescents. Adopted 9 September 2022. "Before starting melatonin or any supplement in their children, parents should discuss this decision with a pediatric health care professional." aasm.org. Checked September 3, 2026.
15. Malow BA, Byars K, Johnson K, et al.; Sleep Committee of the Autism Treatment Network. A practice pathway for the identification, evaluation, and management of insomnia in children and adolescents with autism spectrum disorders. Pediatrics. 2012;130(Suppl 2):S106–S124. PMID 23118242. Screen for medical contributors first, then behavioral strategies, then consider melatonin under supervision. doi:10.1542/peds.2012-0900I
16. Piller A, McHugh Conlin J, Glennon TJ, et al. Systematic review of sensory-based interventions for children and youth (2015–2024). Frontiers in Pediatrics. 2025;13:1720179. PMID 41321460. Strong evidence for deep pressure tactile input. doi:10.3389/fped.2025.1720179
17. Bonuck K, Freeman K, Chervin RD, Xu L. Sleep-disordered breathing in a population-based cohort: behavioral outcomes at 4 and 7 years. Pediatrics. 2012;129(4):e857–e865. PMID 22392181. About 11,000 children; sleep-disordered breathing symptoms predicted 20–100% higher odds of behavioral difficulties at 4 and 7, persisting after symptom resolution. doi:10.1542/peds.2011-1402

Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment.