Healthy Sleep Habits, Happy Child
When to Start Sleep Training, #2
February 21, 2022

Found in age groups

Healthy Sleep Habits, Happy Child

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Healthy Sleep Habits, Happy Child

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A Healthy Child Needs a Healthy Brain, A Healthy Brain Needs Healthy Sleep

If you have not already done so, please read Blog Posts 1 through 5 that describe how sleep is important and beneficial. I will post specific information for parents and children based on my book, “Healthy Sleep Habits, Happy Child.” Please do not be put off by my book’s length. This is a reference book. Read only the topic of interest to you.

Blog 67When to Start Sleep Training, #2

When to Start Sleep Training

Blog Posts 49 and 57 discusses beginning sleep training as early as possible. What about letting your child cry at night to help your child sleep better using Extinction or Graduated extinction (Blog Post 24)? My book includes several parent reports describing how and why some parents allowed their children to cry to help them sleep better during the first weeks of life. But many find this objectionable for theoretical reasons. What are the facts regarding allowing very young infants to cry in order to help them sleep better?

  • One study showed that the more frequently mothers ignored their infant’s crying in the first nine weeks, the less frequently their infants cried in the following nine weeks. No adverse effects were noted regarding the mother-infant bond. “We found that crying at home did not differentiate between secure and insecure attachments” (Attachment & Human Development, 2000).
  • A second study asked the question: “Have you ever tried leaving your baby to cry it out during this time?” Here is their data:
Age of Child   Never/Once (%) A Few Times (%)  Often(%)  
Newborn (40-41 weeks
Gestational age)
63 29* 8
3 months 38 49 13*
6 months 40 52 8
18 months 32 37 31

The reason that I am showing the actual data is to emphasize that at term, 37% of mothers, and at 3 months, 62% of mothers allowed their child to cry sometimes in order to help their child sleep. This is in contrast to a popular misconception that nothing can or should be done to help children sleep before the age of 4 months.

Here are some of their findings and conclusions:

*:  Leaving an infant to cry it out a few times at term or often at 3 months was significantly associated with less crying at 18 months.

Leaving the child to cry it out “Was not associated with either adverse behavioural effects on infant development or infant-mother attachment at 18 months of age. We neither recommend leaving an infant to cry out nor responding immediately. Rather, most mothers appear to intuitively follow a differential responsiveness approach with most of them responding immediately at term and starting to adopt a differential approach from 3 months onward. Leaving an infant cry it out might not reflect parental neglect but it may rather reflect authoritative parenting which includes both limit setting and high levels of emotional warmth. If leaving infants to cry it out is occurring within the context of a warm mother-infant relationship, no adverse impacts have been demonstrated.” (Journal of Child Psychology and Psychiatry, 2020)

  • A third study asked mothers “Have you ever tried leaving your baby to “cry out’?” Cry out Users are mothers who used cry out “a few times” or “frequently”. Nonusers were those who reported not using cry out or used “cry out” only once. Here is their data:
Age of Child     Nonusers or Used Once(%) Users (%)  
3 months   77 23
6 months   55 45
18 months   39 61

Comparing ‘Users’ and ‘Nonusers’ (excluding those who used only once), it was observed, at 6 months, there were no differences in measurements of caregiver sensitivity (refers to direct observation of affectionate caregiving that is sensitive and responsive to the infant’s needs). Also, at 20 months, there was no difference in direct measurements of infant-mother attachment. By 12 months of age, infants of ‘users’ , compared to ‘nonusers’, had an easier temperament, fewer night wakings, and longer sleep durations.

Among ‘users’, “early adopters” used cry out at 3 months while “late adopters” started to use cry out at 6 months. Comparing early adopters and late adopters, at 12 months of age, there was less crying at bedtime and fewer night wakings in the early adopter group.

“Our data suggests that cry out contributes to the trajectory of infant development, including potentially preventing later problems. Infants of cry out users had reduced negative temperament, reduced night waking, and increased hours of sleep at 12 months of age, compared to nonusers. Cry out is not associated with infant-maternal attachment.” (Journal of Developmental and Behavioral pediatrics, 2020).


  1. My baby is 10 weeks old and I have been trying to lay him down drowsy but awake. I’m finding that he often fusses until he is over tired and then it’s very difficult to get him down. He ends up pecking at my chest and clawing at me until I finally nurse him sleep.

    1. Simply shorten the interval of wakefulness by 5-10 minute increments until you see that he fusses less or not at all during your soothing. Please let us know how it goes.

  2. I want to say that you changed my life and have changed thousands of mothers’ lives here in Brazil. I’m a doctor who became a sleep consultant at FSI after devouring all your books and applying them to my children. Today we are pioneers in the method of extinction, and thousands of families have been transformed into happy families. All because of you. Thank you, thank you, and thank you.

  3. We sleep trained our baby (6 months old) and he started to sleep through the night. But on the fifth night of the training he woke up around 3.30 am and cried till morning. We’ve been putting him to sleep early ~5.30 pm with two day naps. He was fussy all day perhaps because of teething. What can we do at night during teething time to give him some comfort and not create bad sleep habits?

    1. Whenever there is an acute change in your child that might indicate pain or illness, call your child’s doctor. Teething pain disrupting sleep is a myth (Blog Posts 36-37).

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