Here's Everything You Actually Need To Know About The Wonder Weeks

It's normal to feel constantly baffled in the weeks and months after you welcome a new baby. First there’s a learning curve to figure out your baby’s temperament and learn what different cries mean. Just as you think you’ve got it and established a schedule, something changes and you’re back at square one. When we need to learn about developmental milestones or troubleshoot issues like sleep problems, we turn to books and articles for information. Your friends might have even suggested reading about the wonder weeks. But what are the wonder weeks? This way of connecting milestones to behavior was created by Hetty van de Ritj and Frans Plooij, authors of a book by the same name.

Simply put, the wonder weeks are those especially fussy periods over the course of the first year-and-a-half of your baby's life when they want to be held or nursed all the time, sleep quality declines, and there is generally more crying and crankiness going on. In The Wonder Weeks book, van de Ritj and Plooij link these fussy periods to a baby's mental development:

"Research has shown that babies make 10 major, predictable, age-linked changes – or leaps – during their first 20 months of their lives. During this time, they will learn more than in any other time. With each leap comes a drastic change in your baby’s mental development, which affects not only his mood, but also his health, intelligence, sleeping patterns and the 'three Cs' (crying, clinging and crankiness)."

All parents, whether or not they read the book, can't help but notice these fussy periods in their children. Sometimes we call it a sleep regression or speculate that baby must be getting a new tooth. Inevitably, the child emerges from the difficult period with a new skill such as the ability to stand up, or increased progress in something like language acquisition. I've certainly observed these developmental leaps in my own two kids. Knowing that the hard behavior will pay off with something positive makes it easier to get through. It also reminds us of parenting's great truth: every stage is temporary; this too shall pass.

While parents will certainly notice the wonder weeks as they unfold, reading the book makes you more prepared by knowing when to expect them (perhaps you might line up extra help from family or friends if you know the following week is going to be rough) and understanding what's happening in your child's brain at that specific time. The Wonder Weeks can't offer a magical solution for a baby who is waking up in the middle of the night to practice standing up, but it can help you focus on the positive side — that all of this fussing will lead to very healthy and important growth.

Over email, Romper talked to The Wonder Weeks CEO Xaviera Plas-Plooij. She explains that the first edition of the book was published in Holland in 1992. It made its American debut in 2003 and the most recent version, released in September 2017, provides "very good information about healthy sleeping habits of infants and the correlation with leaps. We show parents why babies sleep like they do (hint: these sleep ‘problems’ we think we have… they might actually be a sign of good development of your baby!)."

Overall, "our book doesn’t tell parents what to do or how to do something," Plast-Plooij explains. "We give parents insights into their baby's developing mind so that they can make their own choices. And the other huge difference between other books and The Wonder Weeks is that we only write about the mental development of babies. Other books give information about how much milk a baby needs, etc."

The book offers the most comprehensive information, says Plast-Plooij, but if you don't want to read another book right now, there are several Wonder Weeks apps, including an audio book and milestone memory keeper.

Check out Romper's new video series, Bearing The Motherload, where disagreeing parents from different sides of an issue sit down with a mediator and talk about how to support (and not judge) each other’s parenting perspectives. New episodes air Mondays on Facebook.