Sleep Like a Baby!

Sleep Physiology

Adult sleep

  • Progress through the non-REM sleep stages into deeper and deeper sleep before entering a REM period (where level of brain activity is similar to being awake)
  • Cycle repeats every ~90-110 minutes, with REM making up 20-25% of sleep

Infant sleep

  • Circadian rhythms most influenced by light, so when a baby is born after being in a uterus for 40 weeks, it cannot easily differentiate day from night
  • Early infancy: REM starts immediately upon falling asleep and makes up about 50% of the 50 minute sleep cycles
  • By 6 months: Sleep cycle is more similar to adult sleep
  • Transition is thought to be responsible for the “4-month sleep regression” (when infants seem to regress in terms of the amount of time they’re sleeping at once—typically presents as more night-time awakenings)

Newborns (0-4 months)

Average sleep in 24 hours: 16-20 hours!

Sleep patterns: 1-4 hour sleep periods followed by 1-2 hour awake periods

  • 50-minute sleep cycles = usually with an arousal at the end of each
  • Lots of REM = active sleep
    • Infant REM can consistent of movements such as smiling, frowning, sucking, and limb twitching, so sometimes parents are concerned that their baby is never getting restful sleep even when they actually are

Amount of day-time sleep = amount of night-time sleep

Periodic breathing (first 4 weeks)

Infants (4-12 months)

AAP recommends minimum and maximum sleep times (2016): 12-16 hours

Sleep pattern:

  • Day night differentiation develops between 6 weeks and 3 months
  • Sleep periods of 3-4 hours at 4-5 months
  • 6-8 hour periods at 6 months (no need for overnight feed after 6 months)
  • 70-80% of babies sleep through the night by 9 months
  • Nap 2-4 hours in 2 naps throughout day

Night-time arousals still occur every 90-120 min, but babies should be learning to self-soothe and return to full sleep

Common misconception regarding solid food: introducing solid foods helps to create the ability to sleep through the night, which is not true. This is all due to physiologic processes at work. Advise parents to not introduce solids too early in hopes that it will help the baby sleep through the night. 

Gross motor milestones that can disrupt sleep:

  • Rolling over (4-6 months)
  • Pulling to stand (9-12 months)
  • Separation anxiety (12 months)

Toddlers (1-2 yrs) and Preschool Age (3-5 yrs)

Toddlers (1-2 yrs)

  • Recommended sleep in 24 hours: 11-14 hours (including naps)
  • Sleep pattern: usually naps once daily, 1.5-3.5 hours

Preschool age (3-5 yrs)

  • Recommended sleep in 24 hours: 10-13 hours (including naps)
  • Sleep pattern: Napping declines, most stop by 5 years of age

SIDS and Sleep-Related Infant Deaths

Approximately 3500 infants die annually in the US from sleep-related deaths, including sudden infant death syndrome (SIDS)

  • Rate had not changed much since the 1990s

2016 AAP recommendations from the Task Force on SIDS*: 

  1. “Back to Sleep” for every sleep until age 1 yr
  2. Firm, flat sleep surface
  3. Keep soft objects and loose bedding away from the infant’s sleep area
  4. Room sharing without bed sharing for at least 6 months
  5. Consider offering a pacifier at nap time and bedtime once breastfeeding has been established
  6. Breastfeeding is recommended
  7. Avoid alcohol, tobacco, and other substances
  8. Obtain regular prenatal care and pediatric care, including immunizations

*Evidence to inform these recommendations is largely based on retrospective case-control studies

Common Pediatric Sleep Problems

Sleep Training 

Several different methods without a ton of high-quality evidence

Classic method – “cry-it-out” – Ferber method

  • Goal is to self-soothe – parents delay response or don’t respond at all to cries over night
  • Critics say this disrupts baby’s bond with parents

2016 study in Pediatrics: Behavioral interventions for infant sleep problems

  • 43 infants aged 6-16 months with parent-reported “sleep problems”
    • Group 1 = Control (education about infant sleep)
    • Group 2 = Bedtime fading
    • Group 3 = Graduated extinction
  • Results measured by parent activity monitors, sleep diaries, salivary cortisol levels (infant stress), and “strange situation procedure” (attachment)
    • Strange situation procedure = observe response when parents leave and come back in certain situations and compare this to when strangers enter and leave the room
  • Findings:
    • Both intervention groups had decreased time to sleep onset by 10 min or more
    • Only graduated extinction had significant decrease in nighttime awakenings
    • All groups had increase in total nightly sleep,
    • All groups had same stress and attachment measures
    • All groups showed improvement in reported maternal stress at 12-month follow-up, but occurred more quickly in intervention groups

No data to show that this helps or hurts long-term (study out of Australia showed no difference in children’s sleep, behavior or parent relationship at 6 years of age), and 20% of babies don’t respond at all. 

Further reading (and listening)!

Blog post based on Med-Peds Forum talk by Lindsey Mahoney, PGY3

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