Wonder Weeks Are The Key To Calming Your Fussy Baby

Ever wonder what wonder weeks are? They may be the answer to your parenting prayers.

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When my son was around 4 months old, I was pretty sure that my normally smiley, sweet, angel baby had suddenly been swapped with a miserable little creature who cried all the time and simply would not sleep. Like, at all. It. Was. Brutal. And just as suddenly as he’d started acting like a sleep-deprived monster, my child’s sunny disposition returned. After some research, I discovered my baby was probably experiencing what’s commonly known (and feared by parents everywhere) as the four-month sleep regression. While researching my kid’s behavior during a precious moment of peace, I stumbled across the phrase “wonder weeks” several times, and it seemed to completely describe what we were going through with the sleep regression. Interestingly, it also explained other fussy behavior during what they say are milestone months of a child’s development. If your little one is experiencing sleep regression, separation anxiety, or simply can’t be soothed, the key to calming them may be understanding wonder weeks. I spoke to Xaviera Plas, CEO and co-author of The Wonder Weeks, about everything you need to know about wonder weeks (and how you can use that information to plan ahead for big developmental changes).

What the heck is a wonder week?

“Wonder weeks are developmental leaps,” Plas explains. “Until not so long ago, we thought babies developed gradually. Now, we know that development occurs in leaps. It takes a brain change to enable a baby to learn and do new things.” Plas’ parents, Dutch-born researchers Frans Plooij and Hetty van de Rijt, discovered that several primate species showed regression periods when the baby primates clung more closely to their mothers. Their initial findings led them to wonder (pun intended) if human babies would behave similarly during periods of developmental growth. Plooij and van de Rijt’s theories were correct, and they turned their research into a groundbreaking book. In 1992, they published the first version of The Wonder Weeks in Dutch. The book is now a tool for parents with fussy babies everywhere. Their research has been backed up by studies out of Britain, Spain, and the Netherlands. In a study of Catalonian infants, researchers at the University of Girona in Spain corroborated Plooij and van de Rijt’s theory that infant development occurs in leaps. According to the study, “There is evidence of major reorganizations in psychological development. These reorganizations appear to be marked by discontinuities, that is, sudden spurts or changes in the behavior patterns [of infants].” Thanks to her parents’ research, Plas says, “We now know exactly when a baby will make a developmental leap, a wonder week. The Wonder Weeks informs parents about these leaps (10 leaps in the first 20 months), when they are, what the brain change is all about, what a parent can expect after their baby took the leap, and most important, how parents can help their baby to make the most out of each leap.”

But wonder weeks aren’t exactly wonderful.

They do, however, indicate major milestones in your child’s development and growth. Plas tells HealthyWay that identifying a wonder week is easy: Just look for the three Cs: Clinging, Crying, Cranky. Oh boy. Now, before you plan to drop your kid off at Grandma’s and hop on the fastest flight out of town, remember: Your baby needs you most during a wonder week. “What would you do if your whole world changed drastically and suddenly?” asks Plas. “You would be clinging on to the only people you know (parents), you would be crying, and cranky, too, right? And if everything changed…you would lose your appetite, too, and you surely wouldn’t allow yourself a good night’s rest!” Even though it can be completely frustrating and overwhelming, this is how your child is going to deal with the first phase of a wonder week. You may also notice that during a wonder week, your baby wants to nurse nonstop and wakes up often during the night even if they’re usually a good sleeper. “If you think about all of these signs, you will notice that they are all signs of stress,” says Plas. “The start of each wonder week is a brain change, which is a lot to deal with for a baby.” Understanding that your child is about to go through or is going through a wonder week can help you plan ahead for fussy behavior. For example, you may want to reschedule that family vacation to the Bahamas if your baby will be going through a wonder week during that time. Lazing the day away in a beachside cabana might sound like your idea of paradise, but to baby, the stress of going through big neurological changes may be compounded by being in an unfamiliar location or different sleeping space.

Good news: You can comfort your baby during a wonder week.

“What your baby wants most of all when going through a leap is to get to know and familiarize itself with the new perceptional world he or she has entered with this wonder week,” says Plas. “This is why parents need to familiarize themselves with the perceptual world of that specific leap. It will help parents to really understand what their baby is going through. This way, parents can understand and help their baby much better. Plus, when a baby is helped to understand the new perceptional world, the fussy phase is shorter. Good bonus!” One way to really put yourself in your baby’s booties during a wonder week is to familiarize yourself with each wonder week well before it begins. Nicole Johnson, creator of the Baby Sleep Site, says, “It’s best for you not to create new long-term habits for a short-term problem.” That’s why Johnson developed a handy chart of the most common wonder weeks your child will experience. Parents, familiarize yourselves with this chart. Put it in your Google calendar. Get it tattooed on your arm. Do whatever it takes to memorize each developmental milestone and the corresponding wonder week. You’ll thank me later. For example, my baby slept through the night almost from birth. Then (as I mentioned earlier), he went through a four-month sleep regression. The first couple of nights, I tried letting him cry it out. Let’s just say it didn’t work. He cried for hours, even after I caved and tucked him into bed with me. A few days later, when I stumbled across Johnson’s chart, I realized, Oh, hey, this might be a wonder week. According to the wonder weeks chart,  right around four months, your child hits a big growth spurt. So, had I understood in advance that my baby was going to be cranky because he was growing, crying because his brain was learning something new, and clinging to me for comfort because he didn’t understand what was happening, I might not have gotten so incredibly frustrated with him, which would have been less stressful for both of us. During a wonder week, your baby may not nap or sleep consistently through the night. “We do often need to give our little ones more support during a wonder week, but if you can avoid going overboard and ‘extreme’ in how you handle it, you will get through it faster and back to better sleep faster,” says Johnson. “If you don’t normally bed-share, for example, if you begin bed-sharing, you are communicating that this is the new sleeping arrangement, and it’s not easy to change it back once the wonder week is over,” she explains. “If you need to, go ahead and sleep in your little one’s room or in a bed next to him or her. It’s a lot easier to get yourself out of their room than them out of yours.”

Sunny days, chasing the clouds (of wonder weeks) away…

Remember, parents: This too shall pass! The crankiness, crying, and clingy behavior your baby exhibits during a wonder week will eventually go away as your child passes from a wonder week into what’s called a sunny week. Praise be! So just to recap what we’ve learned so far, a wonder week happens in three stages. We’ve covered the first two: the brain change, which happens in leaps, and the fussy stage (the three Cs), which is when parents can help reduce the amount of stress baby experiences during a wonder week. The third stage is what Plas likes to cheekily call “The Week of Wonder,” or when your baby finally connects the dots and can apply the developmental change he or she just experienced to their new understanding of the world. After all this, says Plas, is a sunny week, or “a period that nothing changes in the brain, a period in which a baby understands the perceptual world it lives in. Until a baby is—like being struck by lightning—going through another brain change and thus back to another leap forward!” Parents can enjoy the sunny weeks by sticking to their child’s normal routines while still exposing them to new places, foods, and things. Sunny weeks are a great time to take trips with little ones because they’ll be more able to adapt to their new surroundings during a sunny week. During sunny weeks, though, parents should also be looking ahead to future wonder weeks, so they’re not totally ambushed during their child’s next big neurological development.

Get yourself the Wonder Weeks app ASAP.

“I decided to [download the Wonder Weeks app] because at about 5 weeks, Naomi became really fussy, and I was concerned she might be sick. I googled it and stumbled upon the wonder weeks,” says first-time mom Tracy Jarrell. “What it was describing sounded like what she was going through, so I downloaded the app. It has seemed to line up pretty well with her leaps and has helped because it helps me as a parent understand what she is going through developmentally and how to help get through the leaps with activities that helps her use the new connections she has made,” Jarrell says. “It has also reassured me as a parent that these are learning stages, so the clingy fussiness is just part of her learning.” Mom Kayla Hanks also downloaded the Wonder Weeks app after a friend suggested she try it. “My friend stated that this app was a lifesaver for being a first time mommy with twins,” she says. “I feel that in those first months, it definitely helped. I kind of felt like it gave me a heads up that my son would be experiencing increased fussing. My son is now over a year old, and I feel like I have a better grasp on his moods without the app.” The Wonder Weeks app (available from iTunes and Google Play) essentially creates a personalized developmental growth chart for your baby, so you know when your child’s wonder weeks are coming up (because while wonder weeks do happen during certain specific week ranges, your baby’s wonder weeks are likely different from another baby’s). The app also helps parents by teaching specific activities and coping techniques that apply to each wonder week as your child experiences it. The Wonder Weeks app isn’t free, but trust me, it’s worth the $2.99 to download, and the other in-app purchases paid for themselves a thousand times over the first time my baby experienced a wonder week. To get the most out of the app, Plas suggests, “Please always enter the due date (not birth date) of your baby because leaps are calculated by due date. And if you have any questions, ask us on Facebook, and we’ll always answer them!” We’re coming up on eight months with my munchkin, and according to my wonder weeks chart, that means we’re headed straight for another sleep regression (say it ain’t so!). But this time, thanks to the Wonder Weeks app (and lots of coffee), we’re prepared for the sleepless—and fortunately temporary—nights ahead.

Katie Martin
Katie Raye Martin is a freelance writer, navy wife, new mom, and chocoholic. In addition to HealthyWay, she has contributed to NextGenMilSpouse, a blog for the millennial military spouse, and Pregnant Chicken, a pregnancy blog. Since welcoming her first son a few months ago, Katie has become a pregnancy expert and cloth diapering connoisseur. When she’s not writing (or changing diapers) Katie is training for her first half-marathon.

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