What is biologically normal infant sleep?

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In our culture, we learn from an early age that babies should be happy sleeping alone. Visit any pre-school and you will see the children playing with the dolls, then lying them down in plastic play cots when it’s time for sleep. In most movies and TV shows, babies sleep happily in cots, often in their own bedrooms, with only a lullaby needed for baby to drift off to sleep.

So is it any wonder that new parents expect the same of their newborn babies?

These new parents come home with their sweet-smelling bundle of joy, place them down into the brand-new cot with the organic cotton sheets, matching the freshly painted walls of the beautifully decorated nursery, then walk out, ready for a nap themselves…

Suddenly, their baby starts to cry.

They walk back in and quickly pick their baby up. Baby stops crying. Relief.

They place their baby back in the cot. But once again, baby screams.

'Hang on', they think in a panic, 'what is wrong with my baby?! Why won’t she fall asleep by herself in the cot? Why will she only sleep in my arms? Why does she wake up as soon as I put her down? Why does she wake through the night and only settle with a feed? How come she was sleeping well, and is now waking constantly again?'

All these concerns are valid and common, and they highlight one of the biggest issues in our society related to our smallest humans. This issue is unrealistic expectations when it comes to biologically normal infant sleep: 

  • The normal infant needs frequent feeding overnight
  • The normal infant prefers to sleep close to an adult caregiver, with preference usually given to the birth mother, whose smell and taste is familiar
  • The normal infant needs help to fall asleep, through feeding, motion, warmth and comfort
  • The normal infant cries when they are put down and left alone, to alert an adult caregiver to pick them up again and keep them safe
  • The normal infant may have bouts of frequent waking when they are going through a sleep progression due to a phase of rapid physical, mental or emotional development

So why are these behaviours normal? And how do we know that they are normal?

For the answer to these questions, we need to look at our babies from a basic, biological point of view. Nature is clever and our baby’s biology gives us lots of hints about the best ways to nurture them and keep them happy.

Why does my baby need frequent feeds overnight?

Human infants have small stomachs and breastmilk is easily digested. Our milk is similar to other primate milk in that it is low in fat and protein(1), which suggests that it is a type of milk that’s designed to be fed continuously. This is the first clever way for nature to ensure that we keep our babies close. It may be seen by some to be inconvenient that our babies want to breastfeed so often, but what better way to ensure they are always safe and close to their mother?

Artificial milk, made from cow or goat’s milk, contain more of the protein casein. This makes them more difficult for a human baby to digest (2), so these babies may feed less often. However, if you think that switching to formula will mean your baby sleeps more independently, think again! Babies’ needs are complex and they will wake for more than just food. They will wake seeking comfort too and this is normal and appropriate.

Why does my baby prefer to sleep close to me?

Your baby has spent the past 10 months living and growing inside your body. They have never known what it means to be separate from their mother and now that they are on the outside, it is just a matter of them slowly adapting to being in a different environment. Your baby’s individual temperament will determine how much sleep they need and how much time they are happy to spend sleeping away from you. Though you will hear that most babies sleep for 14 hours a day, that is an average. The range has been noted to be 9.7-15.9 hours (3). If you want to maximise their sleep, most babies will sleep for longer if they are in your arms or on your chest - and this is normal.

Is your baby getting enough sleep?

Some babies are perfectly happy to spend hours sleeping in their own space. Others will barely tolerate a few minutes. As your baby adjusts to life outside the womb, they will slowly start to learn that the world is safe. They also learn that sleeping alone for periods of time is OK, as long as their care-givers are predictable, reliable and responsive to their cries and needs.

Read more about your newborn baby

Why does my baby need my help to fall asleep?

Babies commonly need some form of parental input or assistance to fall (and stay) asleep. Many love to fall asleep while they are feeding. This is another example of a clever trick developed by nature as a way to help mothers nurture their babies. When babies breastfeed (or when they are skin-to-skin with a parent), their brains release a hormone called oxytocin. Oxytocin makes both baby and mother (or the other parent) feel loved and sleepy (4). Helping your baby off to sleep by feeding them and allowing this process to occur is perfectly normal - and is also beneficial to your baby’s developing brain.

In addition to feeding, babies will often like to be rocked, cuddled or bounced to sleep. This can seem frustrating to the parent who has been told, by both helpful family members or health professionals, that babies should be placed down awake and encouraged to fall asleep by themselves. This is often an unrealistic way for a baby to fall asleep and can cause endless tears for both baby and parents.

Why does my baby wake up and cry every time I put her down to sleep?

Humans are primates, and are referred to as a “carrying species”. This means that our young are programmed to want to be held and carried by their parents, most of the time. A baby who has fallen asleep in their parent's arms, will often wake up and call out if they are placed down on a cold, hard surface. This is nature being clever again: babies are helpless and as such, are primitively programmed to fear predators in the same way as other young mammals. Their best defence mechanism when they fear they have been abandoned is to cry so that an adult comes to pick them up and keep them safe (5).

Adapting to life with a newborn can be difficult, and accommodating their profound need to be close when they sleep can offer challenges for which many parents are unprepared.

Read more on ways to cope when you feel overwhelmed

Why is my baby waking frequently again when she was sleeping well?

Babies’ sleep development is not linear– there are many ups and downs within the first two years. The major brain changes that occur during periods of intense emotional, physical and mental development may mean that a baby who was previously sleeping through may suddenly wake frequently or take a long time settling to sleep. You may have heard these termed “sleep regressions”, but in fact, they are a sign that your baby is developing and progressing and their sleep is becoming more like that of adults. “Sleep progression” is, therefore, a more accurate term!

Read more about sleep and development

The bottom line is this: it is biologically normal for your infant to want to be close to you throughout the day and night, and to need your help and presence to sleep. It is also normal for them to wake frequently, to feed and seek comfort.

Meeting these needs by being responsive and sensitive to your baby will ultimately help to program their immature brain to recognise their world as safe, and their parents as reliable. This will nurture confidence, resilience and empathy.

Concerned your child's sleep may still be outside the range of normal?

Read more on when sleep isn't normal

Contributed by: Georgina Dowden, IBCLC, Registered Nurse, Registered Midwife, Little Sparklers Director 

Banner image credit: Vida Images

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  1. Ballard O, Morrow AL. Human milk composition: nutrients and bioactive factors. Pediatr Clin North Am. 2013;60(1):49‐74. doi:10.1016/j.pcl.2012.10.002
  2. Martin CR, Ling PR, Blackburn GL. Review of Infant Feeding: Key Features of Breast Milk and Infant Formula. Nutrients. 2016;8(5):279. Published 2016 May 11. doi:10.3390/nu8050279
  3. Galland BC, Taylor BJ, Elder DE, Herbison P. Normal sleep patterns in infants and children: a systematic review of observational studies. Sleep Med Rev. 2012;16(3):213‐222. doi:10.1016/j.smrv.2011.06.001
  4. Jillian S. Hardin, Nancy Aaron Jones, Krystal D. Mize, Melannie Platt. Parent-Training with Kangaroo Care Impacts Infant Neurophysiological Development & Mother-Infant Neuroendocrine Activity. Infant Behavior and Development, 2020; 58: 101416 DOI: 10.1016/j.infbeh.2019.101416
  5. McKenna, J. Sleeping with your baby: A Parent’s Guide to Cosleeping. 3rd ed. Platypus Media; 2012