The Happiest Baby on the Block

The New Way to Calm Crying and Help Your Newborn Baby Sleep Longer

By: Harvey Karp

Published: 2015

Read: 2020


Why do babies cry so much? One of the reasons is because babies are born immature. The brains of babies have not finished developing yet when they come out of the womb. Babies are born about three months too soon and miss a “fourth trimester” inside the womb. This makes it difficult for babies to deal with the many abrupt changes in their environment. Missing the calming rhythms of the womb, babies may cry a lot.

You can help babies adjust to life outside womb by imitating the conditions inside the womb. This triggers the baby’s natural calming reflex. Triggering this reflex requires precise actions.

This book suggests five “S’s” that help soothe babies and reduce colicky crying.

  • Swaddling (snug wrapping).
  • Side/stomach position (to calm the baby, never for sleep).
  • Shushing (low-pitched rumbling white noise).
  • Swinging (rhythmic, small motions).
  • Sucking (nipple, finger, pacifier).

The trick is to figure out how and when to do apply these techniques and what combination works for your baby.

Worth Reading

A practical, detailed and convincing guide to understanding why babies sometimes cry a lot and the things you can do to try and soothe them. We will undoubtedly be testing a lot of these ideas.

The book is quite repetitive, but that doesn’t detract from its usefulness too much.

Key Takeaways

  • Babies are born immature.
    • Their brain limitations make it difficult to adjust to the change in environment.
  • Help babies adjust by mimicking the conditions inside the womb.
    • Also: consistent response to develop secure attachment (low stress).

Key Concepts


  • Babies cry out of instinct.
    • They are trying to attract parental attention.
    • They are not trying to manipulate (yet).
      • Over time, crying becomes more intentional and directed.
  • Be predictable, consistent and kind in your response.
    • Secure attachment is the goal.
    • Nurturing your baby helps to develop confidence and trust, sense of security.
    • You can worry about spoiling / teaching bad habits later (around nine months).


  • Frequent, prolonged and intense crying or fussiness.
    • It starts around 2 weeks, peaks at 8 weeks, ends at 12 weeks.
    • Comes and goes abruptly.
    • Often during or after feeding.
    • Worse in the evening.
    • Occurs in healthy infants.

Possible cause of colicky crying: the missing fourth trimester

  • Babies are born before their brains are fully developed – their brains only have:
    • Life support systems (blood pressure, breathing).
    • Reflexes (sneeze, suck, swallow, cry).
    • Perception (senses).
    • Muscle control (limited).
    • State control (turn attention on and off).
  • Babies are deprived of the calming rhythms of the womb.
    • Babies have difficulties with over-stimulation (sudden noises, flailing arms, etc.)
    • Babies have difficulties with under-stimulation (silent room).
  • Colic is a baby’s response to the abrupt change in environment.
    • Some babies are better than others.
    • It depends on the baby’s temperament and brain maturity (state control).

Calming reflex

  • Babies are born with a number of in-born reflexes, that are:
    • Reliable.
    • Automatic.
    • Turned on by specific triggers, thresholds.
  • Examples of baby reflexes:
    • Crying, sneezing, rooting (feeding), stepping, Moro (falling).
  • Calming reflex.
    • Likely evolved to keep babies from moving into risky positions inside the womb.

The 5 S’s that turn on the calming reflex

  • Swaddling.
    • Wrapping the baby imitates the continuous touch and snug cuddling of the womb.
    • Being wrapped prevents over-stimulation and helps the baby focus.
    • Prevents babies to roll over on their stomach (during first four months).
    • DUDU wrap: down-up-down-up.
    • Don’t: bend arms, too loose, too hot, small blanket, blanket touches head, all day long.
    • You can stop swaddling after four months.
  • Side/stomach position.
    • Side position = calming reflex.
      • Stimulates womb-like sensation in the inner ear (similar to fetus position).
      • Reverse breast feeding hold, football hold, over-the-shoulder hold.
    • Back position = Moro reflex.
      • May cause a panicky feeling.
      • But, the back position it is the only safe position to sleep.
  • Shushing.
    • Mimics whooshing, low rumble sounds heard inside the womb.
    • Also helps babies sleep through the night post fourth trimester as the calming reflex fades.
    • Low pitched, monotonous droning white noise.
    • Adjust intensity:
      • Loud, high-pitch when crying (90dB).
      • Softer, low-pitch when calm (65-70 dB).
    • Don’t: all day long, high-pitched or irregular white noise during sleep.
  • Swinging.
    • Vigorous motion similar to what was experienced in the womb.
      • Start fast and jiggly, then slow down.
    • Support the head, but let it wobble gently (by shaking the bum).
    • Windshield wiper technique.
    • Don’t: shake, misalign head, neck and body.
  • Sucking.
    • Nutritive (feeding) or non-nutritive (pacifier) sucking.
    • Lowers heart rate, blood pressure and stress levels.
    • Reverse psychology to train baby mouth muscles to hold on to pacifier (through gentle tug).
    • Don’t: pacifier before breastfeeding routine is established, chemicals, sweets, dirt, strings.


  • Newborns:
    • Sleep 14-18 hours.
    • About 50% of sleep is REM sleep (active, finicky sleep).
    • Sleep cycles are about one hour (about 90 minutes for adults).
  • Wake-and-sleep.
    • Once in bed, wake up the baby.
    • Baby will fall asleep again quickly (hopefully).
    • This helps the baby to self-soothe (fall asleep by herself in the crib).
  • Schedules.
    • Flexible schedules (approximate times) work well.
    • Dream feed: between 10 PM and midnight.
    • Have a routine: low lights, white noise, bath, massage, milk, swaddle.

Other colic remedies

  • Massaging.
  • Walks outside.
  • Check for other issues that may cause colic:
    • Food allergies.
    • Constipation.
    • Too much or too little feeding.

Against SIDS

  • Only let baby sleep on the back.
  • Breast-feed.
  • Avoid over-heating and over-cooling.
  • Sleep in the same room as the baby.
  • Swaddle.
  • Pacifier at bed-time.
  • Don’t sleep with the baby, don’t sleep on a couch, sofa, etc.
  • No pillows, toys or loose bedding.
  • Supervised tummy-time during the day.

Red flags

  • Persistent moaning.
  • Shrill cry.
  • Vomiting (>30 grams, >5 times a day, green or yellow).
  • Change in stool.
  • Fussing during eating.
  • Abnormal temperature (<36.4C, >38C).
  • Irritability.
  • Lethargy.
  • Poor weight gain.

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