Harvey Karp's 5 S's, Explained
Swaddle, side, shush, swing, suck — what each of the five S's does, why they work together, and how to run the shushing step at the right volume.
Based on the idea that the first 3 months are a "fourth trimester" where babies benefit from womb-mimicking stimulation. The calming reflex is strongest during this period.
Swaddle
Wrap snugly with arms at sides. Recreates the womb's containment and prevents the Moro (startle) reflex from waking baby. This is the foundation for the other S's.
Side/Stomach
Hold baby on their side or stomach for calming (never for sleep — always place on back to sleep per AAP guidelines). The "football hold" works well.
Shush
Loud, sustained "SHHHH" near baby's ear. Mimics blood flowing through uterine arteries (75-90 dB in the womb). Match crying volume, then decrease. A sound machine can supplement this.
Swing
Small, rapid jiggling movements (1-2 inches). Not shaking — always support the head. Mimics the constant motion of the womb. A swing or car ride also works.
Suck
Offer a pacifier, clean finger, or breast. Non-nutritive sucking triggers the calming reflex and is associated with reduced SIDS risk. Often the "finishing touch."
For informational purposes only. Always consult your pediatrician for personalized guidance.