Yes, The Fourth Trimester Is Real—And It’s Not Easy

It’s not your fault your newborn cries all the time. Blame the fourth trimester.

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There were plenty of sweet newborn snuggles when we brought our son home from the hospital, but there were also so many moments when my husband and I, baby books in hand, stared down at our crying newborn wondering, WTF do we do now?! Contrary to what we started to think, we weren’t the world’s worst first-time parents. It turns out there’s a reason our baby—and most newborns!—are so fussy. It’s called the fourth trimester, it affects both mom and newborn baby, and no one really tells you about it. But understanding the fourth trimester—a phrase that pediatrician and baby whisperer Harvey Karp, MD, coined to describe the first three months of a baby’s life—is crucial to getting through those tough first weeks at home with baby. We spoke to Karp, along with OB-GYN Heather Bartos, MD, to learn exactly what the fourth trimester is, how it affects newborns, and tips for surviving this tricky time at home with a new baby.

My OB-GYN didn’t tell me there was a fourth trimester! What is it?

If you are pregnant or have been pregnant, you know that pregnancy is broken into three trimesters, with the third one lasting twice as long as the first two (okay, so that’s not true, but it sure feels like it does). So why did your OB-GYN not mention this mysterious fourth trimester? Karp, who is the author of the Happiest Baby on the Block, uses this phrase to describe the first three months outside the womb, during which a baby goes through an intense period of change and development. According to the baby geniuses who developed the Wonder Weeks theory, in the first three months outside the womb, your baby will experience several mental leaps, and their little bodies rapidly mature, which is why your baby is extremely cranky during the fourth trimester. It’s hard work doing all that growing!

“Babies have an innate neurological response called the calming reflex … that gets triggered by rocking, shushing, etc.” —Harvey Karp, MD

Because of this rapid mental and physical development, Karp believes that babies are born too soon, even if they make it right up to their due date. Babies have to be born at 9 months because otherwise they’d be too big to pass through the birth canal. But if it were up to them, says Karp, they’d prefer a few more weeks inside the womb. “The fourth trimester is a metaphorical term, but it is absolutely a real thing!” Karp tells HealthyWay. “It is the few-month window following birth when babies are almost magically calmed and soothed by rhythmic sensations that remind them of being in the womb. It’s not just a theory, it’s biology. Babies have an innate neurological response called the calming reflex—a virtual off-switch for crying an on-switch for sleep—that gets triggered by rocking, shushing, etc.” Typically, babies who are having a tough time adjusting to life outside the womb constantly cry, especially toward the end of the day. They’re not trying to torture you, I promise. They’re simply trying to communicate their desire to be back in the cozy confines of the womb. Since that’s obviously not an option, Karp suggests the next best thing: Recreate the womb experience for your baby using certain soothing techniques.

How to Handle the Fourth Trimester: The 5 S’s will save your sanity.

Is the fourth trimester preventing you from bonding with your new baby as much as you’d like? Are you frantically googling phrases like “how to stop baby crying in the middle of the night” or “how to make it look like you got a full eight hours when you really only got two”? If that sounds like your situation, stop what you’re doing right now and memorize what I’m about to share with you. (You can thank me later, when your baby is sleeping peacefully in his crib.) Actually, you can thank Karp, who swears that his techniques for soothing baby are the next best thing to coming up with a highly realistic uterus impersonation. Says Karp, “In my work researching colicky babies, I’ve observed five womb-mimicking techniques—used throughout time and across cultures—that effectively calm babies. To make it simple for parents, I called them the 5 S’s: swaddling, side/stomach position, shushing, swinging, and sucking. Each one of these steps triggers the calming reflex and sends babies into a peaceful bliss.”

The First S: Learn to make a baby burrito.

Karp’s first S stands for swaddle. By the third trimester, baby was tucked tightly in the womb with little room to wiggle about. Outside the womb, they’re still not in control of their movements, so when they accidentally move their arm or kick a leg, it can be startling and scary. That’s where swaddling comes in. Swaddling your baby tightly recreates that snug, womb-like feeling and usually has an immediate calming effect on newborns.

The Second S: Sometimes side or tummy is okay.

But never to sleep! The only safe sleeping position for a baby is flat on their back, with no loose blankets or toys in the crib. If you’re holding a fussy baby, though, try holding her on her side or even her tummy. It should have a calming effect, especially if you’re swinging at the same time. When baby is calm or has drifted to sleep, then lay her flat on her back.

The Third S: Shhhhh!

Placing a baby in a totally silent room for sleep is kind of the worst idea ever. The womb was a pretty loud place, and babies calm more quickly when there’s some ambient noise in the background. You can either learn to shush like a pro (tip: way louder than you think you need to) or pick up a white noise machine to mimic those womb-like sounds.

The Fourth S: Swing, swang, swung?

According to Karp, babies bounce around in the womb a lot, which makes sense. Every time mom moved, baby moved too. Instead of rocking slowly in a chair to calm a crying baby, use a shorter, faster, swinging motion. Note that this is in no way the same as shaking your baby. It’s easy to get frustrated with a constantly crying baby. If you get angry or frustrated, hand the baby to your partner or another caregiver and take a break to calm down before returning to baby.

The Fifth S: Suck it, mom.

A lot of parents don’t want to give baby a pacifier because they’re afraid of nipple confusion early on. But if you have a crying baby, a pacifier might be just the trick to calming them down. That’s because babies are born with the urge to suck, even if they aren’t hungry.

I need more! What are some other calming techniques I can use in the fourth trimester?

“Things like babywearing and white noise machines are in fact 5 S’s techniques,” says Karp. “When you wear your baby, to her, it’s hardly different than being in your belly—she’s warm, snug, and constantly in motion. Swaddling works so well for sleep because, like babywearing, it reminds your baby of the womb’s embrace.” Looking for a good swaddle? I recommend the Karp’s Happiest Baby Sleepea Swaddle (hey, he is the expert!) or an Ergo Swaddler for easy wrapping. Both are moderately priced at around $25 and are waaaaaay easier than trying to snugly wrap your baby in a regular blanket. As for carriers, there are so many babywearing options, it’s kind of mind boggling. I loved my Sakura Bloom Sling when my son was a newborn, but he quickly outgrew it for daily use. To find a baby carrier that’s right for you, I suggest speaking to a certified babywearing expert (yes, they exist), who you can find through Babywearing International. “Whether you shush or use white noise, a hair dryer, or a vacuum cleaner, these are all loud, continuous womb-like sounds. As I’m sure you know, the rhythmic motion of car rides (and stroller rides) make babies deliciously drowsy,” says Karp. One mom I know absolutely swears by the Shusher, while another has a taped recording of the hair dryer that she can’t leave home without. And a word of advice from a mom who’s been there: Make sure you’re sufficiently alert when going for a car ride or using a device like the hair dryer to soothe your baby to sleep. Falling asleep at the wheel (or with a running hair dryer in your hand) is obviously dangerous. Once little one falls asleep, take a nap too if you need one.

The fourth trimester affects mom too.

I, like everyone else in the world, saw the photos of Kate Middleton looking oh-so-glam mere hours after giving birth to her third child. But I’d be willing to bet my whole stash of frozen breastmilk that the minute Kate and Will arrived home at Kensington Palace, Kate ran straight to the freezer, grabbed a bag of frozen peas, and placed them right on her ah, royal assets. How do I know this?

“The biggest thing no one tells you about the fourth trimester is how hard it is trying to take care of yourself … when you are up all night and constantly caring for a helpless baby.”  —Heather Bartos, MD

Because the fourth trimester doesn’t just affect babies. All moms, even duchesses, experience the fourth trimester, though in a different way from baby. After I gave birth, I didn’t even recognize myself. I felt like I had lost control of my own body. I sat on an ice pack for days and then cried when I needed that ice pack for my engorged breasts as my milk came in. “The biggest thing no one tells you about the fourth trimester is how hard it is trying to take care of yourself (showering, sleeping, quiet time) when you are up all night and constantly caring for a helpless baby,” says OB-GYN Heather Bartos. Bartos says that things like stretch marks and linea nigra don’t just magically disappear after giving birth. It’s hard to embrace these changes, so Bartos shared her favorite self-care tips for dealing with a postpartum body during the fourth trimester.

Stretch Marks

Even if you didn’t get stretch marks during pregnancy, you may get them postpartum. [Postpartum stretch marks] happen when skin rapidly changes (like shrinking after that 9-pound kid!)—so keep moisturizing after bathing, and also using something like a belly band can help,” says Bartos.

Linea Nigra

Linea nigra is the name for that dark vertical line some women get on their belly during pregnancy. Bartos says that the melanin changes in your skin do take a while to fade, but eventually the linea nigra will go away. In the meantime, try to keep your tummy out of the sun.

Engorged Breasts

Engorged breasts are the worst. Typically, you’ll experience engorgement three to five days after baby is born as your milk comes in or sometimes if it’s been a while since a nursing session. To reduce the likelihood of engorgement, Bartos says, “pump or feed as soon as possible. If you’re in a pinch, try hand expressing milk to ‘get the edge off.’” If you don’t have a breast pump yet, get one! They’re usually free or fairly inexpensive through your insurance. I’ll be honest though, my insurance-supplied breast pump did not work for me. Instead, I purchased a cheapie battery-operated travel pump, and it worked like a charm. All this is to say that if pumping isn’t working out, it may be the pump, so don’t be afraid to try a different kind.

Self-Care During the Fourth Trimester

While it can be hard for mom to find a free moment to relax, Bartos recommends taking time to complete daily meditation and low-impact exercises that can really help reduce stress. Here are her favorite practices (and you only need about 15 minutes to complete them!):

  • Alternate nostril breathing (1 minute): This premise is simple. Sit somewhere. You can sit up straight and cross your legs to look cooler. Take your index finger and put it to the side of your nose. Plug one nostril and take a deep breath in through the one that’s not plugged. Exhale through the same nostril. Repeat using the other finger and other nostril. The benefits of this exercise? Scientifically, it can reduce blood pressure but it also balances out your energy and does relax you.
  • Legs up the wall (5 minutes). Also known as Inverted Lake, this mild inverted yoga pose is known for a wide range of health benefits—improved digestion, brain function, relaxation, and sleep—and for its anti-aging effects. Ancient Hindu scriptures claim that this pose hides wrinkles in addition to banishing old age and death. While true yogis can do this pose from 30 minutes to several hours, we everyday gals can benefit from just 5 minutes of this a day.
  • Meditation (10 minutes) When I think of meditation, I think of a long, dreamy process, but in truth, you can do a beneficial mindful meditation in less than 10 minutes. (Heck, you can do it in just one!) If you’re new to the practice, there are guided meditations to take you through the steps. Try this 7-minute loving kindness meditation by meditation mama Megan Winkler. Apps like Calm (iOS and Android) and Headspace (iOS and Android) and hypnotherapy apps by Andrew Johnson are other options that provide a short respite from everyday stresses.

Don’t be afraid to ask for help during the fourth trimester.

“I think you should seek help any time you’re worried about your baby,” emphasizes Karp. “The 5 S’s soothe most colicky babies, so it’s really the first thing to try. There could be a medical concern if you’re confident you’ve mastered the precise techniques and your baby is still fussing a lot. …It’s always smart to get your pediatrician’s opinion.” That goes for mamas too. If you feel that something isn’t right with your body, don’t be afraid to reach out to your OB-GYN for postpartum care—postpartum depression and postpartum anxiety are more common than you’d think. If you just need a little TLC, you know what I’ve found? Sometimes the 5 S’s work on adults too. So if you’re feeling tired or down, grab that ratty blanket, swaddle yourself on the couch with a white noise machine, and take a nap to recharge.

Yes, The Fourth Trimester Is Real—And It’s Not Easy

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.