Dr. Harvey Karp’s 5 S’s: How to Calm and Soothe a Fussy Baby

Dr. Harvey Karp, in his book The Happiest Baby on the Block, explains that babies are actually born about three months earlier than they should be. If they stayed in the womb any longer, their heads would be too big to pass through the birth canal, and their bodies too large for the mother to carry.

That’s why the first few months of life are sometimes called the “fourth trimester.” During this time, our job is to create an environment that feels as close as possible to the womb — warm, cozy, and reassuring — so the baby can make up for that lost time.

If you’ve been wondering how to calm a fussy baby, this idea is key. When babies feel safe and comforted, their bodies relax, and they can sleep better, eat better, and grow with confidence.

In his book, Dr. Karp shares the famous 5 S’s — simple, effective ways to help your newborn feel secure and calm during those early months. Below, I’ll walk you through each of them and explain why following these steps makes such a difference. 🌙💛

The importance of comforting your baby

It has been every day more common in our society the belief that we "should not spoil our babies". That if we rock or nurse them to sleep, give a pacifier to calm them down, or give everything they need right away, they will always need those things and be "spoiled".

This belief is creating even more fussy babies and more sleep struggles than ever. To calm a fussy baby, the answer isn’t strict schedules or forcing independence — it’s connection. Babies sleep better and feel calmer when they feel safe, understood, and supported.

Instead of focusing on what books say your baby “should” do, pay attention to what your baby is showing you. Every baby communicates through behavior — you just need to listen.

Guides and articles are helpful, but they can not dictated how your baby needs to behave. Some things are just normal and we just need to adapt to them. Believing something is “wrong” only creates anxiety and guilt.

When you trust your instincts and comfort your baby when they need you, they learn the world is safe. And that safety leads to relaxation, better sleep, and true independence — naturally. 💛

S #1 - Swaddle

Wrap the baby tightly to mimic the womb's tight space and help with moro reflexes.

Swaddling helps recreate the snug, cozy feeling of the womb. When wrapped properly, your baby feels secure and comforted — and that can make a huge difference when you’re figuring out how to calm your fussy baby.

Many newborns startle easily and wake themselves up with their own arm movements. Swaddling gently limits those movements, helping your baby relax and sleep more soundly. Just make sure to follow the safety guidelines for their age.

S #2 - Side/stomach position

Hold your baby on their stomach against your chest, or on their side

Dr. Karp discovered (and I’ve seen it proven time and time again with the babies I’ve worked with) that babies calm much faster when held on their side or stomach — because that’s how they spent their time in the womb!

This position helps with the feeling of falling that often startles babies when they’re on their back). Try holding your baby on their stomach against your chest, or across your forearm, on their side, to help them feel safe and settled.

👉 Once your baby is calm or asleep, always place them on their back for safe sleep.

S #3 - Shushing

Making a "shushing" noise near the baby's ear to mimic womb sounds.

The womb wasn’t a quiet place — it was full of rhythmic sounds like blood flow and your heartbeat. That’s why “shushing” sounds, white noise, or even a gentle fan can work wonders.

A steady shushing noise helps recreate that familiar sound environment, signaling to your baby that they’re safe. Use your own voice or a white noise machine to help soothe them, specially during fussy times.

S #4 - Swing

Gentle, rhythmic motion, like rocking or bouncing.

Babies are used to constant motion before birth — every step you took rocked them! Gentle movement helps organize their nervous system and can quickly calm crying or fussiness.

Try gentle rocking, swaying, or using a baby swing. The key is rhythmic and small movements — never fast or rough. When trying to calm a fussy baby, movement can be one of the most effective tools.

S #5 - Sucking

Offer a pacifier or let the baby nurse, as sucking is naturally calming.

Sucking is one of a baby’s most natural reflexes and one of their most powerful ways to self-soothe. Whether it’s breastfeeding, a pacifier, or a clean finger, sucking helps your baby relax, lower their heart rate, and feel secure.

Don’t worry about “bad habits” at this stage — during the first few months, sucking is a healthy and necessary comfort mechanism. It’s nature’s way of helping your baby calm down and regulate themselves.

Bringing It All Together 💛

Dr. Harvey Karp’s 5 S’s work because they recreate the calm, familiar environment of the womb — helping your baby feel safe, understood, and deeply cared for.

Each “S” plays a role in teaching your baby that the world outside the womb can be just as safe and comforting. And I can say from experience — I’ve seen these techniques work wonders with the babies I’ve supported. When parents start using the 5 S’s with patience and consistency, their babies not only cry less but also begin to sleep longer and settle more easily.

If you’re still struggling to figure out how to calm your fussy baby or want a plan that fits your baby’s unique rhythm, I’d love to help. I offer 1:1 sleep consultations where we look closely at your baby’s patterns and create gentle, personalized strategies to help your whole family rest better. 🌙

You can learn more or schedule a session here: Sono Sleep Solutions