Understanding Infant Sleep – 3 things every new parent needs to know

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Babies are born earth side with little concept of night and day and often have little remorse for new sleep deprived parents.  The following are three important factors to help new parents understand their infant’s sleep.


Circadian rhythms are not developed in infants at birth

Newborn sleep is not governed by strong circadian rhythms. This is largely because as a fetus, they are tuned into their mothers’ physiological cues about day and night. Once a fetus is born, this intimate hormonal connection is broken and newborns must develop their own circadian rhythm of hormone production.

While it may take several months for your infant’s sleep to be more consistent and regulate, studies show that circadian rhythms begin to develop in the first days after birth (source).


There are two important hormones that promote or deter sleep

These hormones are melatonin and cortisol. In regards to sleep, melatonin is the hormone responsible for helping us to feel sleepy and less alert. It generally starts to peak in the blood stream around 9 pm and levels stay elevated for about 12 hours (source). Melatonin is produced and controlled by the pineal gland, a tiny pea-sized gland.

Babies are not good producers of melatonin, but production starts to regulate around 3-4 months of age. 

Cortisol is known as the stress hormone but is also responsible for waking us up. Cortisol levels are at their lowest roughly 3-5 hours after we fall asleep and gradually rise, peaking in the morning around 8-9 am (source).

In order to help infants sleep, parents and care givers need to help facilitate the production of melatonin at night and reduce the chances of cortisol being produced.  The following will help you help your baby sleep better:

  • Lights in general and in particular blue lights from tv’s and computer screens cause a decrease in melatonin production. When our retinas sense light it signals to the brain that it’s time to be awake.  When the pineal gland receives this message from the brain, the release of melatonin is stopped (source). Because babies struggle to make melatonin, it is very important to reduce any unnecessary exposure to light when they are learning to sleep and regulating their circadian rhythms.                                    
  • In babies and children, one of the main reasons cortisol levels can be high is from sleep deprivation (source). Sleep deprivation leads to stress which leads to increased cortisol.
  • Putting a baby to bed later or shortening their naps is counter intuitive because it just causes further sleep deprivation (source).
  • “Sleep begets sleep”.
  • Establishing regular wake and bedtimes as well as exposing your infant to light during the day (not while sleeping) will help your infant’s melatonin production and circadian rhythm regulate.


Infant sleep cycles are different than adult sleep cycles

The average adult will have sleep cycles that are roughly 90-100 minutes. When we first fall asleep, we pass through a few light sleep stages and then enter a deeper state of sleep. After the 3rd stage of sleep, we enter the deepest stage known as REM or “rapid eye movement”. It is in the REM stage that we dream. After REM sleep, we either wake up, or start the stages over (source).

Newborns also have stages and cycles of sleep, but there are differences.

I have observed infant sleep cycles averaging in length from 30-45 minutes and some studies indicate they may last as long as 50-60 minutes (source).

There are 5 stages of sleep in an infant under 3-4 months of age. REM sleep and non-REM. There are 4 stages of non-REM sleep: 

  • stage 1 – drowsiness, eyes may open and close, dozing, in and out of sleep.
  • stage 2 – light sleep, the baby moves and may jump or startle with sounds.
  • stage 3 – deep sleep, the baby is quiet and does not move.
  • Stage 4 – very deep sleep, the baby is quiet and does not move (source).

Newborns generally start out in active (REM) sleep and then enter non-REM sleep. About half of an infants sleep will be in REM sleep.

Because of the various stages and depths of infant sleep, babies tend to be lighter sleepers and float in and out of sleep often. When in the lighter stages of sleep and infant may wake very easily with sounds or light. This tendency to awaken easily appears to have a protective factor that may reduce the chances of oxygen deprivation, which is a known risk factor for SIDS (source).

Around 3-4 months of age, infants sleep patterns start to become more adult like. They no longer plunge directly into REM sleep after falling asleep and they start to spend more time in slow-wave ‘deep’ sleep (source).


How can new parents help their babies sleep?

The topic of newborn sleep is fascinating, but most sleep deprived parents just want to know when their baby will sleep through the night and what they can to to help their baby sleep better. Here are a few things to keep in mind:

  • The phrase “sleeping through the night” is relative and means different things for each family. One family may state it as from the time they the parents go to sleep and wake for the day. Another family may say it is the time from midnight to 8 am. In the sleep world and with infant sleep consultants and educators, sleeping through the night is generally a 10-12 hour stretch of time.
  • It is normal for both adults and infants to wake multiple times during a nap or night time sleep. This is known as a sleep cycle transfer. New parents often mistake these sleep cycle transfers or periods of light transitional sleep as their infant waking. Be careful not to rush to your baby too soon and allow them the opportunity to self-soothe and put themselves back to sleep. This is a skill they need to learn how to do on their own, or you will be doing it for them. If these unnecessary interventions are done regularly, you baby will have trouble learning to go back to sleep on their own (remember it is normal for them to wake often), or it will be come a habit and they will wake because they have learned to wake at a certain point during their sleep. Be patient and observant when responding to your infant and learn their quirks and cues.
  • Be very careful with night time light and activity before bed and during night feeds. As stated above, light will disrupt melatonin production and give the false sense that it is time to be awake. Feeds during the night should be all about business. Low or no nights, and no social talking or interacting.
  • Good goals for an infant nap are roughly 1.5-2.5 hours and eating upon waking from each nap.


If you feel your baby isn’t sleeping as well as they could be, please don’t hesitate to contact us. We would be happy to help you and your baby sleep better.


The content contained in this blog is for informational and educational purposes only. It is not intended as medical advice or to replace the advice of any medical professional. It is based on our opinions and experience working with newborns and their families. Other’s opinions may vary. It does not represent the views of any affiliated organizations. The reader understands that term “Babynurse” is often a word used to describe a newborn caregiver. However, unless otherwise disclosed, we are not licensed nurses in any state. By reading and/or utilizing any information or suggestions contained in this blog, the reader acknowledges that we are not medical professionals and agrees to and waives any claim, known or unknown, past, present or future.

© 2018 Bishop Enterprises, LLC All Rights Reserved


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