Ah wonder weeks! You’ve heard of them – but what do they mean? When will they happen? And most importantly – how do you survive them?

Here’s what you need to know about the sometimes-less-than-wonderful wonder weeks!

Oh so ‘wonderful’ wonder weeks!

Being a new parent is full of wonder. Wondering if you will ever sleep again. Eat a hot meal. Speak a complete sentence to your spouse. And just when you think your baby has settled into something vaguely resembling a routine, everything changes! Enter wonder weeks. The Australian Breastfeeding Association describes these as fussy periods when your child is “clingier, crankier, cries more and sleeps less”. Sounds like fun times. So what are the wonder weeks, what do they mean – and how do you survive them?

So what are the wonder weeks?

Wonder weeks are pretty amazing times for your baby! Just as your baby has growth spurts where they go through big changes, so too does their brain! Called ‘wonder weeks’ by Dutch doctors Plooij and van de Rijt, these changes in mental development happen at 10 predictable times in the first 20 months of your baby’s life. At each, your baby is making a big leap forward – meaning their brains are changing, they are capable of perceiving new things about the world and are ready to learn new things.

Wonder weeks can be a less amazing for you. Because of the drastic changes happening in your baby’s brain, they can feel frustrated and overwhelmed by new abilities they haven’t yet mastered. This can lead to ‘stormy weeks’, regression periods that can affect your baby’s mood, appetite, sleep and behaviour, with more crying, clinging and crankiness. The good news is that after each of these changes, your baby is able to learn new things and is often much happier. These times are called ‘sunny weeks’. You can read more about the science behind the wonder weeks here.

What’s happening for your baby at each wonder week?

Here’s what’s happening for your baby at each of the wonder weeks or ‘leaps’ forward in your baby’s development. Tip: use your baby’s expected due date to work out when to expect the wonder weeks – for this reason premmie babes may reach the wonder weeks later.

Leap 1: the world of changing sensations

The first wonder week happens at around 4 to 5 weeks after your baby’s due date. This is when your baby starts to become more aware of their senses, inside and out. There are so many things to process and respond to! Feeling the movements of their arms and legs, and the touch of hands, water and clothes on their body. Smelling and tasting milk, and feeling movements in their stomach and bowel. Hearing sounds and seeing the movement of lights and colours in the world around them. All this can be overwhelming and overstimulating for your baby! The good news is that after this leap, your baby will start to be more alert and show more interest in their world. You might notice them being less startled by touch, responding to sounds and smells – and starting to smile in response to familiar faces!

Leap 2: the world of patterns

The second wonder week happens at around 8 weeks, when your baby starts to recognise simple patterns in the world around them.​ Your baby might stare intently at patterns of light or colour and listen to familiar sounds, like the tick of a clock. Your baby will also start to be aware of patterns in the way their body moves, such as moving their arms and hands in and out of view. After this leap, you might notice your baby looking at patterns, discovering parts of their body and showing signs of trying to grasp toys.

Leap 3: the world of smooth transitions

The third wonder week happens at around 11 to 12 weeks. Your baby will no longer make the jerky movements of a newborn, starting to move their arms and legs more smoothly. Your baby may start waving their arms towards things they want to touch, and start to turn their head to follow sights and sounds. Delightfully, your baby may start to grin and laugh!

Leap 4: the world of events

At around 19 weeks the fourth wonder week happens, and your baby begins to understand that some events cause another in the world around them. Your baby will become even more active as they try to experiment in making things happen! You will notice your baby trying to do many new things, as well as better grasping skills, more interest in toys – and signs of boredom or impatience!

Leap 5: the world of relationships

The fifth wonder week at around 26 weeks means your baby begins to understand the relationship between things. Your baby will start to explore, lifting, throwing, looking underneath. This can be the time when your baby starts to show separation anxiety, because they begin to understand the distance between two things – if mum walks away, I can’t get to her!​

Leap 6: the world of categories

The sixth wonder week at around 37 weeks means your baby begins to understand that there are groups or categories in their world. Your baby will start to recognise that some objects, sensations, and people belong together in groups. The way they explore the world may seem very methodical as they use all their senses to understand the similarities and differences in their world.

Leap 7: the world of sequences

At around 46 weeks the seventh wonder week happens where your baby starts to understand sequences, that there is a certain order to doing some things. Your baby may look for what things go together and how they go together before trying to put them together or stack them on top of each other​. Your baby will be able to do simple puzzles, stack toys and understand the order of getting dressed.

Leap 8: the world of programs

Around your baby’s first birthday, at about 55 weeks, the eighth wonder week happens and your baby starts to understand the idea of programs. This builds on the sequences learned at leap 7, where one event leads to another and adds the idea of ‘if-then’. It means your baby can understand that what happens next depends on what just happened – putting on gumboots signals a different activity than putting on slippers. Your baby will become an observer and an experimenter to understand what causes what in their world.

Leap 9: the world of principles

The ninth wonder week happens at around 64 weeks, and your child is able to change between everything learned so far – and will love to play with this!​ You may see your child start to be more skillful with language and physical tasks, and practice emotions – including nagging, negotiating and bargaining – to engage people, get their own way or get you to do something for them. Your child will begin to want to do things themselves, think ahead and understand possessions. These are cute times as your child starts to role play, imitate and understand humour!

Leap 10: the world of systems

Around 75 weeks or 17 months, the tenth wonder week happens where your child understands how to apply what they have learned more flexibly and to adjust their behaviour to changing situations. Your child will start to develop empathy, become less egocentric and start to understand sharing. You will notice better language skills and acting out to test boundaries.

Check out this amazing video of how your baby really sees the world.

Surviving the wonder weeks

Ok, so you know when the storms are coming and why. All that learning and growing is wonderful for your baby – but less so for you, the exhausted caregiver! So how do you survive the wonder weeks?

Expect crankiness and crying. Your baby can cry and be unsettled no matter how well you are caring for them. Remember crying is the only way your baby can communicate with you at the moment. Your baby isn’t trying to get at you and won’t be spoilt if you comfort them. If you think your baby’s crying might be colic, there are some great tips for things to try.

how to settle baby

Expect changes in sleep. Wonder weeks can mess with your baby’s sleep – and yours. Your baby might start waking more or take longer to get settled. If your baby is not sleeping, here’s 7 things to check!

Expect clinginess. It’s normal for babies to be less settled and more clingy at these times. Be patient, this will pass as your baby adjusts to their new stage of development.

Find out how to help your baby. You can read all about each stage and how to help your child’s development in The Wonder Weeks book by Van der Rijt and Plooij.

It’s ok to find it hard. Trying to comfort a crying or unsettled baby can make you feel impatient, frustrated, upset or helpless. These feelings are normal – they don’t mean you’re not a great mum, probably just a weary one!

Look after yourself. Ask for help and take breaks when you can. It’s ok to need support. Check out the Child and Youth Health website or contact the Parent’s Helpline.

Need a laugh? Check out this light-hearted look at why the first year is so damn hard! 


I love my three country kids - and all things writing! Like most mums, I wear lots of hats - writer, children's author, organisational psychologist and the pairer of the odd socks!

Write A Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.