The consensus among sleep specialists is that there are roughly six stages of sleep regression at different ages—when the baby is 4, 6, 8, 12, 18, and 24 months old.

While sleep regression is a common term, there is no medical consensus on its definition. Additionally, little published research exists on infant sleep regression.

Typically, these regressions relate to the various developmental milestones a baby experiences, such as learning to sit up, crawl, and walk.

These regressions can have links to separation anxiety, big life changes, and a desire for independence.

This article explains the stages and possible causes of sleep regressions and other reasons a baby may experience sleep disturbances.

Baby sleeping at a stage of sleep regressionShare on Pinterest
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The term “sleep regression” refers to a period of time when a baby or toddler experiences a negative shift in their sleep back to a previous pattern.

Often, sleep regression signs include:

  • fighting naps or bedtime
  • difficulty falling asleep
  • taking shorter naps or skipping naps
  • frequently waking at night
  • fussing and crying

These changes in sleep patterns can be distressing for a parent or caregiver. However, they are a natural part of early years’ growth.

There is not much current and formal research on infant sleep regressions. However, it seems they occur for various reasons, including:

  • developmental milestones, such as learning to crawl, walk, or talk
  • needing to transition to one nap per day
  • separation anxiety
  • growing desire for independence
  • life changes, such as potty training, moving from crib to bed, or getting a sibling

However, sometimes, what looks like a sleep regression is more of a sleep disruption due to growing pains, teething, hunger, and reflux. Additionally, babies may have trouble falling and staying asleep because they have not established solid sleeping habits.

Every infant is different, and sleep changes in babies and toddlers can vary in timing, duration, and frequency.

However, sleep regressions commonly occur around 4, 6, 8, 12, and 24 months.

Signs include:

  • changes in nap routines
  • waking more frequently at night
  • restless sleep
  • trouble falling back asleep

Four-month sleep regression

Typically, the 4-month sleep regression is the first sleep pattern change babies experience. However, not all babies experience it. It might come a month or so earlier or later for those who do.

Sleep changes at this stage are typically the beginning of a permanent alteration in a baby’s sleep pattern. Around this time, babies start sleeping more like adults and less like infants, so this “regression” typically represents a springboard into more mature sleeping patterns.

Learn more about the 4-month sleep regression timeline.

Six-month sleep regression

Generally, babies around this age wake at night because they are hungry. Maybe they are breastfed and still need a night feed, or perhaps they need to replenish the calories they burned during the day from practicing their scooting, crawling, and sitting-up skills. Separation anxiety and teething are also possible causes of sleep changes at this stage.

Eight-month sleep regression

As with most sleep regressions, this appears to coincide with developmental changes such as learning to pull themselves to a standing position or crawl.

Additionally, some babies get their central incisor teeth between 8 and 12 months, possibly contributing to sleeplessness. Anyone with concerns about teething may ask a pediatrician for advice.

Learn more about the 8-month sleep regression.

Twelve-month sleep regression

Similar to most sleep regressions, the 12-month sleep regression seems to occur due to the baby’s growing skills and awareness of the world around them.

Caregivers keep babies on a regular bedtime routine to help this regression pass.

Eighteen-month sleep regression

Toddlers undergo many changes around the middle of their second year, and some of those changes may contribute to the 18-month sleep regression. One change might be a change in the toddler’s circadian rhythms — more specifically, the 24-hour sleep-wake cycle.

Babies begin establishing a sleep-wake cycle during the first 4 months of life. However, rapid eye movement (REM) and non-rapid eye movement (NREM) change over a person’s lifetime, including the first 5 years of life.

This may cause some toddlers to start fighting their usual bedtime. REM and NREM are sleep phases important for various mental and physical processes.

Additionally, some toddlers go through the 18-month sleep regression because they are dealing with separation anxiety and do not want to be away from their parents or caregivers.

Learn more about the 18-month sleep regression causes, management tips, and self-care for adults.

Twenty-four-month sleep regression

Typically, the 2-year sleep regression is the last one.

Causes may include:

  • life changes such as potty training or moving to a toddler bed
  • return of separation anxiety
  • night terrors, nightmares, and nighttime fears, such as a “monster under the bed”

There are a few ways caregivers can help ease this regression, including:

  • initiating one life change at a time, for example, introducing a toddler bed and then potty training or vice versa
  • increasing wake time between the afternoon nap and bedtime
  • teaching skills to cope with nighttime fear

Sleep regressions can be a difficult time for both babies and caregivers. While every situation will vary, some common techniques may help manage these early life sleep changes, including:

  • establishing a sleep routine for both the infant and caregiver
  • maintaining an active waking-hours schedule to aid tiredness
  • creating a cool, dark environment for sleep
  • waiting before first responding to cries
  • allowing the child to fall asleep in bed rather than elsewhere, to build routine and associations

A sleep regression is an abrupt change in an infant’s sleeping pattern, and many babies experience several stages of sleep regression during the first 2 years of life.

Typically, these sleep regressions have links to the baby’s developmental changes, though other factors, such as teething, can influence shifts in their sleeping habits. For the most part, sleep regressions stop after around the 2-year mark.