The Four Month Sleep Regression

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So… your baby has been sleeping perfectly… until one day, she turned 4 months old, and suddenly everything went downhill…. Oh no!! What happened?!?!

Yup, that’s very common, especially for prop dependent babies. Let me take you through the reasons behind it:

1. There is a reorganisation of sleep at around the 4 month mark

  • Newborns only have 2 stages of sleep (1) REM Sleep (2) Deep Sleep and they spend about 50% in each of those stages. But at around 4 months, the amount of time spent in REM sleep reduces, making way for an additional of 2 stages of light sleep, i.e. Stage 1 & Stage 2 sleep. Their sleep is becoming more like an adult, and REM sleep is now down to 30%.
  • Besides, their little bodies are also going through a lot of change at this age, reaching developmental milestones like rolling over, using hands to explore, smiling, responding to their name, becoming more aware of their surroundings. It is no surprise that this reorganisation and developmental milestones can cause some disruption to your child’s sleep.

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2. Your baby start spending more time in light sleep

  • There is a lot more light sleep now (Stage 1 & Stage 2) when they reach 4 months, hence a baby can be easily woken during these stages of light sleep. Any loud noises, bright light, change in sleep environment that happen during these 2 stages of sleep may easily cause a baby to rouse.
  • As they go through cycles of sleep at night, it is also common that there will be a few naturally occurring wake ups when approaching the end of a sleep cycle. These naturally occurring wake ups may cause partial awakening in the middle of the night. Sometimes, it may be very brief and your baby was able to slide back into another cycle, while sometimes, that brief awakening can lead to a full wake up.

3. Your baby has a lingering sleep prop (e.g. nursing/ rocking/ bottle/ pacifier etc to sleep)

  • For prop dependent babies, the transitioning between sleep cycles can be the cause for constant night wakings. Your 4 month old baby is now more cognitively aware of her surroundings, and notices that the prop isn’t there anymore, leading to a full wake.
  • Hence naturally so, prop dependent babies can become really bad sleepers when they hit the 4 month mark, as they are constantly calling out for you to help them fall back asleep.

So, what can you do? For prop dependent babies, I would highly advice that you start introducing some good habits around sleep… the earlier you tackle this problem, the easier it is.

What you need to know is that babies go through a lot of development in the first few years of life, and some form of regression every now and then is normal. The good news is… it will be a lot easier to breeze through those regressions if your child has learnt the skills to become a great sleeper right from the start 😊

Is your baby going through a four month sleep regression and you don’t know what to do? Contact me and we’ll set up a consultation and go through this step by step together. Email at or call me at +60123542010.

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