The 4-month sleep “regression”

The 4-month sleep “regression”

What is the 4-month sleep regression? Is there such a thing as a 4-month breastfeeding crisis? Throughout the breastfeeding journey, there are many moments of change. In fact, the baby’s entire first year brings many changes. When babies are born, their brain still needs to learn a great lot of things, as they are biologically very immature. They need to learn so many things, such as talking, sitting, walking… and one of the big things they have to learn is to sleep like adults.

What’s going on?

When they are around 4 months old, babies usually start to suddenly sleep “worse” and wake up more often than when they were newborns. Therefore, this phase is also called the 4-month sleep “regression.”* And when this happens, mothers and families worry and think that they have done something wrong or that their baby needs something else:

  • Maybe you didn’t get your baby used to sleeping well enough?
  • Maybe it’s your fault because you have not done any sleep “training”?
  • Maybe your baby gets hungry during the night?
  • Maybe your baby gets hungry because they don’t get enough milk from you?

Or you might simply think you can’t do this anymore and you just need more sleep!

So what is really happening?

The answer to all of the previous questions is no. What really happens is something that all babies go through, regardless of whether they have breast, bottle, or a combination of both. So, the first thing you need to know is that all babies always wake up more often at around 4 months, no matter what they eat.

So they are not hungry?

No, it is very unlikely that your baby is hungry. The 4-month sleep “regression,” which is also sometimes wrongly called a breastfeeding crisis, means that babies now wake up more and more frequently during the night. But this is a developmental leap that is not related at all to their nutrition or any particular type of feeding.

Why do they wake up more now?

At around 4 months, babies learn two new sleep phases, like the ones we adults have, that babies don’t have at birth yet. This makes their sleep more superficial and restless; they move, make noises, and wake up nervous.

But they accept breastfeeding and calm down

Yes, breastfeeding makes it easier for babies to know that everything is going well and that their mother is by their side, even when they are not hungry. Suckling has a magic effect: it relaxes them and makes them sleepy. Breastfeeding is not to blame when they wake up; on the contrary, it is helping, as it makes it easier for babies to get back to sleep.

How long does this last?

For a little while, there’s no way around it. Usually, it takes around a month until your baby learns these new sleep phases. During this time, babies continue to wake up frequently, sometimes as often as every hour, and calm down quickly with breastfeeding.

Are you sure my baby is not hungry?

No, this is not a sign of being hungry. Unfortunately, many families get pushed by poor advice to stop breastfeeding and give their baby a bottle of formula milk (sometimes even with baby cereal in it) at night so they sleep longer.

Does that work?

The first challenge is usually to get an exclusively breastfed baby to accept a bottle. If they never had a bottle before and this is their first experience with it, they are unlikely to take it and may strongly demonstrate their rejection. If a baby has mixed feeding, it is easier for them to take a bottle at night, but it’s still likely that they continue to wake up despite having a bottle. Then, you must resort to alternative methods to put them back to sleep again, as the time spent suckling on the bottle alone will not be enough.

Risk of tooth decay

  • If you do decide to offer formula or breastmilk with baby cereal in a bottle, you need to know that this can increase the risk of tooth decay and obesity. To avoid this, if your baby already has teeth, you have to brush their teeth after feeding and make sure they do not keep the bottle in their mouth throughout the night. On the other hand, to avoid childhood obesity, never force a baby to eat; bottle feeding and giving solid food should also always be on demand so babies can self-regulate.

Do you need more information?

To talk about your individual situation to our experts, you can find them in the consultation channel of our app LactApp, which is free to download for iPhone and Android and where you have a lot of information about breastfeeding and motherhood.


*At LactApp, we prefer to use the word “regression” in quotation marks because, in reality, babies are developing and advancing their development, reaching milestones. The word “regression” is a perception of adults when babies’ sleep pattern does not meet their expectations.

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