Wonder Weeks Leap 1 – William’s Experience

Links to Amazon on this blog are affiliate links*

wonder week 5 leap 1

I was introduced to the Wonder Weeks when Caroline was a few weeks old. I was immediately intrigued and got the free app on my phone.

The app asks for your baby’s due date to calculate prediction on when they will enter what it calls leaps, or “fussy phases”.

“From our research, we are now able to predict, almost to the week, when parents can expect their babies to go through one of these ‘fussy phases’.”

The Wonder Weeks (van de Rijt and Plooij), page 2

I decided to track her phases based on her due date, as well as her birth date, just out of curiosity.

As it turned out, Caroline reached her leaps almost perfectly to the predicted start day…based on her birth date, not due date.

As a result, I tracked her developmental leaps based on her birth date.

The book is absolutely fascinating. I wrote a review on it here.

The app has valuable information and is useful for tracking purposes, but the book has a plethora of information on the skills learned in each leap, and signs to watch for etc.

It even has checklists of abilities that your baby is likely to start showing during each wonder week.

We really enjoyed reading about these leaps, and have decided to follow along with William’s wonder weeks as well.

I, again, tracked both his due date and his birth date in the app to see which he’d line up with. He hit wonder week 5 (leap 1) perfectly- based on his birth date.

If I’d followed his due date instead, it was saying he had over a month before reaching it. It was clear immediately that this wouldn’t be the case.

He’s just finished up the first leap, and he exhibited many of the skills noted in the book.

My goal is to report on all 10 leaps during his first year. I’ll discuss how the leaps went for him, the timing, skills exhibited, etc.

You can find all of our wonder week reports on this leaps and milestones page.

The First Wonder Week

wonder week 5 leap 1 during baby's fifth week of life

Wonder Week 5 is actually the first wonder week. Wonder weeks are labeled by the week that they happen during your baby’s life.

The first leap, or first wonder week, happens during week 5 of your baby’s life. So, it is called wonder week 5.

Specifically, leap 1 (wonder week 5) is referred to as “Wonder Week 5: The World of Changing Sensations”.

“At about 5 weeks, and sometimes as early as 4, your baby will begin to take the first leap forward in his development. New sensations bombard your baby inside and out, and he is usually bewildered by them.”

The Wonder Weeks (van de Rijt and Plooij), page 38

William entered this leap right on time!

Wonder Weeks Chart

Page 47 in the Wonder Weeks book, shows the first checklist of interests and physical changes that may occur during wonder week 5.

For more detailed information, check out the book! Here is our experience with each of the skills:

“No two babies are exactly the same. Each baby has his own preferences, temperament, and physical characteristics, and these will lead him to select things in this new world that he, personally, finds interesting. Where one baby will quickly sample everything, another will be captivated by one special skill.”

The Wonder Weeks (van de Rijt and Plooij), page 16

In other words… your baby may check off everything that is listed on this checklist, or find a few special skills to focus on.


  • Looking at things longer and more often (the book also mentions that they can see farther now, so more things catch their interest). William is definitely doing this!
  • Listening to things more and paying more attention to sounds is also something he’s doing.
  • He is more aware of being touched. He really leans into my snuggles now and rubs his face against mine. When eating, he grabs at my shirt, and he’s doing a lot more intentional grabbing in general.
  • Smells- I didn’t notice him focusing on this skill much, but I also didn’t test it with different smells to see if he’d notice.
  • Smiles for the first time- William gave some definite grins and happy gurgles during this leap.
  • Expressing likes and dislikes more often is something that he’s just barely starting to do now that he’s finished the leap.
  • He is staying awake longer at times, and is definitely more alert when he is awake.
  • He’s also very distracted when nursing. He will scream and scream for food, but then as soon as I sit down with him to feed him, he’s just looking at my face, looking around, and even investigating my nipples. He’s hard to keep focused right now!

Physical Changes:

  • I didn’t notice any breathing changes, but the book mentions breathing more regularly.
  • Startling and trembling less often is something that I noticed a little bit with him.
  • Crying real tears for the first time was something that happened! William has had a couple of real tears.
  • Chokes less, vomits less, and burps less are also mentioned. I’ve noticed specifically that he is burping less often and it is harder and harder to get one out of him!

Signs and Fussiness

William was definitely more fussy during this time.

As the book puts it:

“…your baby goes through a whole set of changes that affect his senses- the way he experiences the world, the way he feels, even the way he digests his food. His whole world feels, looks, smells, and sounds different.”

The Wonder Weeks (van de Rijt and Plooij), page 46

As a result, he’s using a lot more energy figuring things out, and taking it all in. He’s more alert, and just wanting to be up longer.

But that doesn’t mean he’s not tired and needing to sleep!

William had a harder time going to sleep and was more fussy at the starts of nap times- especially during the witching hours (6 pm – midnight was his hardest time).

Prior to this leap, he was also very restless the last hour of his naps. I’ve noticed that this has decreased.

Once he’s finally asleep, he’s sleeping longer.

Once he was out of his leap, and out of his most recent growth spurt (in the 6th week), he was a bit more tired. Almost just in recovery mode.

Now we seem to be coming out of recovery mode, and he is just very alert and happy and enjoying all of his new skills.

He even decided to roll from his belly to his back shortly after this leap! Super early!

I’m always excited to see what the next developmental leap brings. Leap 2 will be arriving around week 8! Check back to the leaps and milestones page to see his progress updates!


Hi there! I’m Katrina (aka Mama). I am a former engineer and chemistry teacher, turned stay at home mom and mom blogger. I have been blogging since 2015, and have taken my love of engineering and science, and tried to applied many of the same methods to my parenting adventure.

I have a huge passion for Babywise and prioritizing sleep for our children. I am mom to 3 (including one angel baby that had trisomy 13). A huge mission of mine is to share her story and legacy. I am a big believer in being real and doing what works for YOUClick here to subscribe to my weekly newsletter to follow our story. 

This blog is intended to be our story and our ideas- including successes and failures along the way. You can also find me published at Today Parenting, Her View From Home, VitamedMD, Love What Matters, and The Mirror. Follow me on Facebook and Pinterest for more parenting tips and to hear more about our journey!

Find me on: Web | Twitter | Facebook