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The 4-month infant sleep regression

If your baby is suddenly waking up frequently at night and resisting naps, you're likely experiencing the 4-month sleep regression, a phase that can be exhausting for both you and your little one. As a fully certified sleep consultant and a mum myself, I understand your concerns and want to reassure you that this phase is a normal part of your baby's development. Most infants go through this regression around the 3-4 month mark, but the good news is, it’s manageable. For those of you feeling overwhelmed by your baby's sudden change in sleep patterns, I'm here to guide you through understanding the 4-month sleep regression and provide practical strategies to help you and your baby through this challenging but totally normal developmental stage. For more detailed information including how sleep works, how babies learn, routines and schedules download the Baby Sleep Guide.

Because I know how busy you probably are, here is everything I'm going to talk about, so you can jump to what you need to know about the 4-month sleep regression before your little one wakes up!

What is a sleep regression?

A sleep regression is a period where a baby or toddler, who previously slept well, suddenly experiences frequent night awakenings, difficulty in falling asleep, sleepless nights, or shorter naps. Sleep regressions are a normal part of development commonly occur around 4, 8, 12, 18 months, and 2 years, during key developmental phases. Don't worry, these regressions should be temporary, usually lasting just a few days to a few weeks. All you need to do is make sure your baby has good sleep hygiene and a consistent sleep routine. However, if your baby's sleep problems are persisting it is worth consulting a sleep specialist to gain strategies to get sleep back on track.

What is the 4-month sleep regression?

The 4-month sleep regression is marked by significant changes in a baby's sleep patterns around four months of age, it is also the only true sleep regression that all baby's go through. This is because at 3-4 months, all baby's sleep architecture changes due to the development of their circadian rhythm (also known as their body clock). During this time, babies also experience rapid brain development and heightened sensory awareness which can also lead to them to waking more frequently especially when transitioning between sleep cycles.

Common signs that your baby is experiencing the 4-month sleep regression are:

Increased night waking
Increased fussiness
Changes in feeding and napping habits
More heightened awareness with how they fall asleep.

To learn how sleep works and how to avoid future sleep regressions, download the Baby Sleep Guide. The guide includes information on how sleep works, how babies learn, awake times, schedules and much more.

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Why babies have a 4-month sleep regression

At 4-months of age, a baby’s sleep changes more than any other point in their lifetime. Although a newborn and 4-month appear the same while sleeping, what is happening in their brain is different.

How long will the 4-month sleep regression last?

The 4-month sleep regression can span a few days to a few months and depends on how parents respond. The child's temperament and their ability to fall asleep independently also influence the length and impact of the sleep regression. Some relaxed and mild tempered babies prefer to fall asleep on their own and do not struggle with sleep once their circadian rhythm has formed. However, when a baby’s sleep association is dependent on their parents, the full effects of the sleep regression are felt, and when a baby won’t sleep, often the whole family suffers from sleep deprivation. If sleep issues persist or there are concerns about a child's sleep habits, consulting a healthcare professional is advisable.

What is happening during the 4-month sleep regression?

During the 4-month sleep regression a perfect storm of development changes are happening in your baby's brain to cause a sudden onset of frequent waking. Here are main developments that are causing the change in your baby's sleep architecture and causing the four-month sleep regression:

1. Formations of Sleep Cycles

Like adults, while babies sleep, their developing brains are going through a sequence of stages called a sleep cycle. The development of the circadian rhythm causes a baby's sleep cycle to become more defined and is the biggest reason babies experience the 4-month sleep regression. Overnight babies go through multiple sleep cycles, and it is when they are transferring to a new sleep cycle that they often wake.

2. Developing a Circadian Rhythm and 24-hour cycles

At 3-4 months of age your baby is developing their circadian rhythm, which causes a more consistent pattern with their sleep wake cycle. Our circadian rhythm, also known as our body clock, controls our sleep and waking rhythms, along with other 24-hour cycles including hunger, thirst, hormone levels, body temperature and intestinal activities.

3. Increase in awareness

Compared to newborns, a 4-month-old baby is much more aware of how they fall asleep (e.g cuddled or rocked). This increase in awareness for many babies leads to a regression in their sleep.

Do all babies experience the 4-month sleep regression?

No, while all 4-month-old babies experience brain development as their circadian rhythm grows, not all babies suffer the 4-month sleep regression. The effects of the sleep regression may not occur or might be very mild when parents have worked on independent sleep strategies with their child as a newborn.

Is it really a sleep regression?

I am frequently asked, "why is my baby having a sleep regression at specific ages?" The answer is often, the disruption in sleep isn’t necessarily a sleep regression rather another problem with similar symptoms such as:

1. Hunger:

A growing baby needs frequent feedings. If your baby wakes up crying and calms down after feeding, hunger might be causing them to wake rather than a sleep regression. If you rely on feeding to sleep, you may be encouraging frequent night wakings.

2. Illness or Discomfort:

A cold, ear infection, or other medical issues can affect sleep. Check for symptoms like fever, congestion, or unusual fussiness.

3. Developmental Leaps:

While these are often the cause of sleep regressions, leaps can also lead to changes in behaviour around sleep and are not sleep regressions per se, but rather adjustments to new skills like rolling or crawling.

4. Environmental Changes:

Changes in the sleeping environment, travel, or disruptions in routine can temporarily affect a baby's sleep.

5. Overstimulation or Overtiredness:

An overstimulated or overtired baby may have difficulty settling into sleep or staying asleep.

6. Sleep Associations:

Dependence on certain conditions or actions to fall asleep (like rocking or feeding) can cause frequent awakenings especially when those conditions have changed during the night.

Will the sleep regression affect my baby’s health and development

Yes, but not always negatively, because sleep regressions are simply the byproduct of your baby developing healthily. However, prolonged sleep disturbances can cause your baby to become over tired, which of course can cause a range of problems such as cat napping, and fussy eating habits. The best way to deal with a sleep regression is, to make sure sleep is a priority.

Why does my baby wake up screaming?

A major factor in the 4-month sleep regression is a baby’s ability to independently transfer sleep cycles. How a baby feels falling asleep, whether feeding or being held, is a very different feeling to waking up alone in bed. When a baby transfers sleep cycles and realises they feel differently to how they did falling asleep they will start crying. Once those same actions are re-created, the little one will fall back asleep.

When will my baby sleep through the night again?

When it comes to the burning question of, when a baby should sleep through the night? Technically, the truth is, no one sleeps through the night, we all briefly wake between sleep cycles. However, if by "through the night" you mean sleeping for a longer, uninterrupted stretch, then you can encourage this by starting to help your baby develop healthy sleep habits like, the ability to self-soothe and connect sleep cycles without external assistance.

6 tips for managing the 4-month sleep regression

For parents struggling with the 4-month sleep regression, try these tips.

Prevent your baby from becoming overtired

Watch your baby’s-tired signs very closely and lay your little one down for a sleep before they become overtired. Both early and late tired signs, along with month by month awake times are listed in the Baby Sleep Guide.

Establish a clear and consistent bedtime routine

Create a predictable sleep routine for your baby to help them understand when their sleep time is approaching.

Encourage the formation of good sleep habits.

Encourage self-settling and re-settling skills with your baby so they can independently transfer and connect sleep cycles. Teaching self-settling is not easy for parents however, time and time again the feedback I receive from parents who have done sleep training is, how pleasantly surprised they were with how quickly their little one learned to self-settle.

Consider what your baby’s sleep association is

Think about how your little one is falling asleep and how this may be contributing to their short naps and night waking.

Create a comfortable sleeping environment.

Consider the sleep environment, is the room dark enough? Is there lot's of external noise? White noise and blackout curtains could be your secret weapon to managing sleep regressions.

Encourage healthy feeding habits

Focus on your baby having full feeds and not snack feeding.

When to ask for help

If the 4-month sleep regression is becoming too much and you are feeling sleep deprived, consider getting some help for you and your baby. Help can come from a parent, friend, parent hotline, general practitioner, or a baby sleep consultant. For more information on navigating the 4-month sleep regression, download the Baby Sleep Guide - 4 -24 months or consider a 1:1 consultation.

Note from Author:

As an Early childhood and primary educator, Mother and baby sleep consultant I have seen first-hand how important sleep is to a child’s long-term development. Working with families to develop healthy sleep habits is a passion of mine. To book a consultation please contact me.

Reference:

Ferber, R. (2013). Solve Your Child’s Sleep Problems. Ebury Publishing

Turgeon, H., & Wright, J. (2015). The Happy Sleeper. Scribe Publications

4-Month Sleep Regression: Everything you need to know!