"My baby was sleeping great, but suddenly wakes up crying all night", "They're fussy for no reason and just want to be held" - Sound familiar? Your baby might be going through a Wonder Week.

What Are Wonder Weeks?

Wonder Weeks is a concept developed by Dutch researchers Hetty van de Rijt and Frans Plooij. It suggests that babies go through 10 mental developmental leaps during their first 20 months.

Wonder Weeks is a popular guide many parents find helpful. However, it won't match every baby exactly, so use it as a general reference.

Signs of a Mental Leap

When a leap begins, your baby may act differently:

Sleeping well then suddenly waking frequently
Refusing breast or bottle or eating less
Fussy and crying for no apparent reason
Not wanting to be separated from mom
Only falling asleep when held

If you notice these changes, think "my baby is growing!"

The 10 Mental Leaps

Leap 1: Week 5 (World of Sensations)

Baby starts experiencing the world more intensely. Senses become sharper, which can be overwhelming.

Changes: More alert, responding to sounds

Leap 2: Week 8 (World of Patterns)

Baby discovers their hands and feet belong to them. Starts recognizing simple patterns.

Changes: Staring at hands, kicking feet playfully

Leap 3: Week 12 (Smooth Transitions)

Movements become smoother. Head control improves, can connect movements.

Changes: Holding head up, reaching for objects

Leap 4: Week 19 (World of Events)

Understands cause and effect. "If I shake this, it makes noise!"

Changes: More interest in toys, interactive play

Leap 5: Week 26 (World of Relationships)

Understands distance and relationships between objects. Separation anxiety often begins.

Changes: Crying when mom leaves, stranger anxiety

Leap 6: Week 37 (World of Categories)

Can classify objects into groups. "This is food, that's a toy."

Changes: Sorting objects, purposeful actions

Leap 7: Week 46 (World of Sequences)

Understands order of events. Anticipates routines like "eat → play → sleep."

Changes: Predicting routines, sequential play

Leap 8: Week 55 (World of Programs)

Plans and executes complex actions. Works through multiple steps to reach a goal.

Changes: Problem-solving attempts, using tools

Leap 9: Week 64 (World of Principles)

Begins understanding rules. Knows what "no" means.

Changes: Testing boundaries, negotiating

Leap 10: Week 75 (World of Systems)

Realizes they're an independent person. Wants to do everything themselves.

Changes: "I do it!" expressions, asserting preferences

How to Handle Wonder Weeks

Extra Cuddles

Babies feel insecure during leaps. Physical contact is the best comfort. Hold them more, speak gently.

Keep Routines Consistent

Maintain regular sleep and feeding times. Consistent routines provide security.

Offer New Stimulation

Provide age-appropriate toys or activities. Help satisfy their curiosity.

Take Care of Yourself Too

Leaps are hard on parents too. Remember: "It's not my fault, baby is just growing." It's okay to ask for help and take breaks.

Frequently Asked Questions

Q: Are Wonder Weeks timing accurate?

They're approximate. Expect ±1-2 weeks variation, and every baby is different. Use as a reference guide.

Q: Do they apply to preemies?

For preemies, calculate from your due date, not birth date.

Q: How long do leaps last?

Usually 1-2 weeks, sometimes up to 3 weeks.

Q: Does every baby show the same signs?

No, symptoms vary. Some babies are very fussy, others barely show it.

Track Baby Changes with BebeSnap

Recording changes during Wonder Weeks helps you spot patterns:

Sleep logs: Check if waking more than usual
Feeding logs: Track intake changes
Notes: Add memos like "extra fussy today"

Looking back, you'll understand "oh, that was a leap!"

References

Wonder Weeks Complete Guide: 10 Mental Leap Stages Explained