6 minute readWhy does sleep regression happen?
“Why?!” is a question many a new parent will ask (or possibly scream at the top of their voice) when faced with a sleep regression — “why me?!”, “why now?!”
Yet in fact, there’s only one true sleep regression, and this typically occurs around the 3-4-month mark — hence, it’s often referred to as the 4-month sleep regression. This happens because your baby’s newborn sleep cycle is transitioning to a more “adult-like” pattern, and is an important part of your baby’s development.
But of course, your baby’s sleep needs are constantly evolving, and this means they’ll often be faced with temporary periods of sleep disruption. So while the so-called 6-month and 9-month sleep regressions are something of a myth, it’s not unusual for your baby’s sleep pattern to be knocked temporarily “off track” at various stages.
What causes temporary sleep disruptions?
These temporary sleep disturbances can be the result of a combination of factors: they often occur alongside significant developmental stages, which can include cognitive advancements as well as physical changes. They can also happen when your baby’s routine is disrupted, such as when transitioning them from a crib to a bed.
These are some of the most common reasons sleep disturbances happen:
Developmental milestones. As babies grow, they learn new things like rolling over, crawling, walking, and talking. This can sometimes make it harder for them to settle down and sleep, as they process these new skills and sensations.
Cognitive growth. Your baby’s brain is rapidly maturing in terms of memory, knowledge, and awareness. As these cognitive functions develop, they may resist sleep or wake up more frequently during the night.
Teething. The physical discomfort of their first teeth emerging may mean your baby wakes up more often or has trouble getting to sleep (although this should last only 3-5 days after the tooth emerges).
Illness. Any kind of illness can temporarily disrupt a baby’s sleep pattern, whether it’s a cold, an infection, or an upset stomach.
Growth spurts. Growth spurts often lead to increased tiredness, but they also cause babies to wake up more often during the night — particularly as they’re often hungrier and may require more nighttime feeds than normal.
Separation anxiety. Emotional factors can also contribute to sleep disturbances, and babies who develop separation anxiety may struggle to sleep due to the unease they feel when being left alone in their crib.
Changes in routine. Most babies favor consistency, so any significant changes in their routine or environment, including adapting to a new bed, traveling, or moving home, can trigger sleep disruptions.
Changing nap timetables. As your baby grows, they’ll need fewer naps during the day. But transitioning them from three daily naps to two, for example, may cause a temporary disruption to their nighttime sleep as they adjust.
What are the signs of sleep regression?
Sleep regression usually happens when your baby is around 3-4 months old, and signals a permanent change in their sleep behaviour. Because it’s such a significant step in their development, this period is often accompanied by a temporary worsening of your baby’s sleep, and they may become more fussy or difficult to settle as they navigate this transition.
Of course, not all babies experience the 4-month sleep regression in the same way — some may become increasingly fussy or clingy around bedtime, for example, while others may wake more frequently during the night or find it harder to settle. Some babies experience very little sleep disruption at all during this stage.
What are the signs of temporary sleep disruption?
As we’ve mentioned, the “official” sleep regression typically rears its head around the 4-month mark for many babies, but most will experience temporary sleep disruptions at various stages throughout their development. These can occur at any time, and may be characterised by one or more of the following:
Increased night wakings. Your baby may start waking up more frequently during the night, even if they previously slept through it.
Difficulty falling asleep. Your baby may take much longer to fall asleep than usual, even if they appear tired.
Resistance to sleep. Your baby may become resistant to bedtime and start fighting sleep altogether.
Shorter naps. Your baby’s daytime naps may become shorter or more erratic — which can impact their nighttime sleeping routine, too.
Increased fussiness or clinginess. Your baby may be particularly fussy or clingy around their normal bedtime.
How to alleviate sleep disturbances
While sleep disruptions often come on suddenly and there aren’t always warning signs that one is on the way, identifying the signs as early as possible can help you put measures in place to help deal with the issues quicker, whether that means adapting your baby’s sleep schedule or simply tempering your own expectations.
By spotting the signs of a sleep disruption early, you may be able to introduce changes such as:
Adjust their bedtime routine
If your baby is overtired, making their bedtime earlier can help prevent them from becoming so exhausted that they resist sleep.
If they seem full of energy at bedtime, moving it slightly later might give them more time to wind down and feel ready for sleep.
Alter their nap schedule
If their daily naps are typically long or frequent, reducing the number or duration of naps can help your baby consolidate more sleep at night.
Conversely, if they’re overtired due to shorter naps, encouraging more daytime sleep may prevent them from becoming too exhausted by bedtime.
Introduce calming pre-sleep activities
A warm bath or a gentle massage before bedtime can soothe and relax your baby so they feel more ready to sleep.
Reading a quiet bedtime story or playing soft, soothing music can become a nightly routine that signals it’s time for bed.
Offer extra comfort and reassurance
If they’re struggling to settle at night, consider spending a little more time holding, cuddling, or rocking your baby before putting them down.
If they wake up frequently during the night, respond with soothing actions such as patting or shushing to reassure them.
Set realistic expectations
Understand that sleep regressions are temporary and a normal part of your baby’s development — nearly all babies have them.
Be prepared for more frequent wake-ups or rough nights, but remind yourself that sleep regressions don’t last forever.
While the 4-month sleep regression is an unwelcome inevitability for most parents (a very lucky few notwithstanding), knowing how to spot the telltale early signs can at least prepare you for what’s to come — and help you come out the other side relatively unscathed. In any case, it’s important to remember that it’s actually a very important stage in your baby’s development, and crucially — it will pass.
Reviewed by Rosey Davidson, Sleep Consultant, founder & CEO, in November 2024.