Growth and development phases that modify baby and child sleep

Your baby slept like an angel and suddenly changed from day to night? The problem with this can be a natural cause: the child’s development and growth.

Your baby’s development and growth in the first year and beyond can cause changes in your sleep. See how leaps in development, spikes in growth, and separation anxiety can interfere with sleep.

The child’s first year is a period of extraordinary change for the whole family. This is an exciting and challenging time, when babies learn to communicate their needs and parents learn how to meet them.

You may think that your baby’s development (such as learning to roll, crawl and walk) and growth has nothing to do with sleep, but the truth is, they go together! Below is a description of the phenomena called developmental leaps, growth spikes, and separation anxiety.

Development leaps

Developmental leaps are acquisitions of specific functional skills that occur at certain times. The pace of development is not constant: there are some periods of accelerated development and others where there is a slowdown.

Every time your baby develops a new skill, he becomes so excited and obsessed with the achievement that he wants to practice it all the time, including in his sleep. In other words, one of the ‘side effects’ of all this work that babies’ brains are doing is that they don’t sleep as well as they do during periods when they’re not working on mastering a new skill. They may even resist established routines.

In the period that immediately precedes the so-called developmental leap, the baby may suddenly feel lost in the world, as their perceptual and cognitive systems have changed, there was neurological maturity, but not enough time to adapt to the changes. Then the world seems strange to him, and the result of the anxiety generated is usually the desire to return to his base, to what is already known to him, namely, Mom! As a result, it is common for them to become more needy, needing more cervix, and there are also often changes in their appetite and sleep.

So, at these stages, you just need to have a little patience and empathy with the baby – after the process of acquiring the new skill (such as laughing, crawling, sitting, interacting, walking) the baby takes a leap in development and demonstrates happiness with the end of the ‘crisis’. In other words, on the one hand, the baby is happy with the new skill and independence that comes with it, and is already able to move away from Mom. On the other hand, she feels anguish and fears about this new situation. This gives you mixed feelings: it’s like a ‘mad dance’ between separation and attachment, where the baby will fluctuate between the two for a while.

The duration of each jump varies, but usually after a few weeks the difficult phase passes and everything returns to normal. Babies and children need loving care, empathy, and new experiences, not expensive toys. Talk to your baby, sing, play with him, read to him. These are key activities for brain development. Developmental leaps do not stop in childhood but continue into adolescence. (1-2).

These acquisitions occur in several aspects: motor development (learning to use muscle groups to sit, walk, run, balance, change positions and others), development of fine motor control (use your hands to eat, draw, dress , playing an instrument, writing, and many other things), language (development of speech, use of body language and gestures, communication and understanding what others say), cognitive development [in the first two years, according to Piaget, sensory development occurs -motor, which includes thinking skills such as learning, understanding, problem solving, reasoning and memory (3)] and social development (interacting and relating to family, friends and teachers, showing cooperation and empathy).

Some variation among children is expected, but an experimentally observed chronology of periods of developmental leaps is as follows:

  • 5 weeks (1 month): baby’s vision improves, he can see patterns in black and white, becomes more interested in his surroundings and can follow objects briefly with his eyes. He spends staying awake for slightly longer periods (about 1 hour or a little longer between naps). It is also at this time that baby starts to cry with tears and smile for the first time or more often than before.
  • 8 weeks (almost 2 months): differences in sounds, smells and tastes become more noticeable. He realizes that the hands and feet belong to the body and starts trying to control these limbs. The baby also begins to experiment with his voice. It is also at this stage that the baby starts to show a little of his personality: it is now that the parents start to notice which things, colors and sounds the baby likes the most. After this jump the baby will be able to turn his head towards something interesting and consciously make sounds. All these new experiences bring insecurity to the baby, who probably seeks more comfort from the mother’s chest. This can make the mother worried if she produces enough breast milk, which is not the case, as production adjusts to demand (see also below on growth peaks).
  • 12 weeks (almost 3 months): the baby discovers more nuances of life: at this age the baby can already see an entire room in the house, turns around when he hears loud sounds, and manages to put his hands together. He’ll watch and mess with his parents’ face and hair, and he’ll find he can scream. After the jump, the baby will practically no longer need support to keep his head up. As with the other jumps, the parents are the safe haven of the baby’s world and he relies on that. He may start to react differently outside the home or in a stranger’s lap. While the baby is very curious to notice the world around him, he is also very sensitive to news and therefore feels more comfortable and safe in the arms of his parents.
  • 19 weeks (4 and a half months): around the 14th. until the 17th. weeks the baby may seem more ‘impatient’. This is one of the longest jumps: it lasts about 4 weeks, but it can be extended for up to 6 weeks. The baby cries more, has extreme mood swings, and wants more attention and cuddle. He manages to reach out and pick up a toy, shake it and put it in his mouth, pass it from hand to hand. He can get his first tooth. The sounds that the baby makes become clearer and more complex, he can make some sounds like ‘baba’, ‘dada’. Everything smells, sounds and tastes different now. He sleeps less. He finds people strange and seeks greater body contact when he is being breastfed. After this jump the baby will be able to turn on his back and stomach down, and vice versa, crawl forward or backward, look carefully at pictures in a book; react by seeing your reflection in the mirror and recognizing your own name.

This is one of the most significant developmental leaps and one in which a greater number of mothers tend to report changes in sleep. Probably because the sleep pattern has seemed to get into a rhythm since the baby was born, and this change is seen as a ‘regression’, in which the baby tends to wake up quite a bit for a few weeks while working on the jump. And since that jump is only completed 1 or 2 weeks before starting work the next one (of 26 weeks), it’s a long period of bad sleep and irritable baby at this stage of life.

  • 26 weeks (6 months): Already in the 23rd week the baby seems to become more ‘difficult’. He seeks greater body contact during play. The baby is already able to coordinate the movements of the arms and legs with the rest of the body. He sits unsupported and puts objects in his mouth. At this age he begins to understand that things can be in, out, up, down, back, in front, and he uses that in his games. He comes to understand that when Mom walks, she will pull away and that scares him, so he complains when Mom leaves. After this jump, the baby will be interested in exploring the house, closets, drawers, finding labels, lifting rugs to look at what’s underneath. He turns around to pay attention to the voices, manages to imitate some sounds, rolls well in both directions and starts leaning on something to stand up. It acquires maturity to receive solid food. This phase can last around 4-5 weeks.
  • 30 weeks (7 months): baby tries to throw himself forward to reach objects, hits one object against another. He can start to crawl, speak a few syllables and better understand the concept of permanence of things. He can wave goodbye. He feels anxiety about strangers.
  • 37 weeks (8 and a half months): the baby becomes ‘temperamental’, has frequent changes in his mood, from cheerful to aggressive and vice versa, or from overly loving to tantrums in a matter of moments. He cries more often. He wants to have more activities and protests if he doesn’t have them! He doesn’t want his diaper changed, he sucks on his fingers. He protests when body contact is broken. He sleeps less, has less appetite, moves less and “talks” less. Sometimes he sits still and daydreamed. The baby is now starting to explore things in a more methodical way. He comes to understand that things can be classified, for example, he knows what is food and what is animal, whether live or in a book. He speaks “mama” and “papa” without distinction of who is the mother or the father. He crawls, points at objects, looks for hidden objects, uses his thumb and index finger to hold objects.
  • 46 weeks (almost 11 months): the baby realizes that there is an order in things and attitudes, for example, putting shoes on their feet and toys in the closets. He then gains an awareness of his own attitudes. Instead of separating objects, it starts to join them. After this jump the baby will be able to point to something or person at your request, will want to ‘talk’ on the phone and stick keys in key holes, look for something you have hidden, try to take off your own clothes. Say “mama” and “daddy” to mom or dad correctly. She stands up for a few seconds, moves more, understands the “no” and simple instructions.
  • 55 weeks (almost 13 months): usually the stage when the baby starts to walk – a very significant leap in development. Speaks more words than “mama” and “papa”. Scribble with chalk.
  • 64 weeks (almost 15 months): the baby combines words and gestures to express what he needs, eats with his hands, empties containers, puts lids on the appropriate containers, imitates people, explores everything in front of him, starts games, points to parts of the body when asked, responds to some instructions (eg, “give me a kiss”), uses a spoon and fork, pushes and pulls toys while walking, plays ball, goes in reverse.
  • 75 weeks (17 months): baby uses about 6 words regularly, likes imitation games, likes to hide toys, feeds a doll, plays ball, dances, sorts toys by color, shape and size. She looks at books alone and scribbles well.

Growth Spurt

Growth spikes are phenomena that refer to the baby’s growth itself, not its development. During peak periods, babies start to request more feeds than usual, as they need more food to grow at this now faster pace. So the baby who slept long periods at night may start waking up more and requesting more feeds. This need usually lasts from a few days to a week, followed by a return to the smaller feeding pattern, but now with the mother’s body adapted to produce more milk.

It is very important to respect the increased demand for breastfeeding, as it is only with free demand that the production of breastmilk adjusts perfectly to the baby’s needs.

During these periods, the mother may misinterpret the baby’s increased demand for feedings – she may feel that her milk is not being enough, or that it is ‘weak’ and think that the solution to the situation is to offer a supplement of artificial milk. However, it is a mistake to offer bottles with artificial milk during these periods, as this undermines nature’s perfect balance of producing milk in line with the demand for feedings. In other words, when giving artificial milk, a powerful stimulus in the breast is lost, the body understands that it does not need that feeding, and starts to produce less and not more as it is necessary!

Common periods of peak growth occur around 7-10 days, 2-3 weeks, 4-6 weeks, 3 months, 4 months, 6 months and 9 months and beyond. The peaks continue to occur throughout the child’s growth, including adolescence, when physical and emotional changes are most noticeable.

Dr. Jeny Thomas, physician and breastfeeding consultant, affiliated with the American Pediatric Association and the Academy of Breastfeeding Medicine reflects on believing in the ability to breastfeed the baby:

“Most women don’t believe that their bodies that created this beautiful baby are capable of breastfeeding the same baby. Research shows that supplement use and early weaning are increasing. Why don’t we believe in our bodies in the postpartum period? I don’t know But I hear every day that the mother is complementing because “my milk doesn’t satisfy you, it’s not enough.” Of course it is. Babies need to be fed all the time – and they need to be with you all the time.

A baby nursing at its mother’s breast is getting components to develop its immune system, activating its thymus, warming up, feeling warm and comfortable, safe from predators, having normal sleep patterns and activating its brain (oh, and even) acquiring food for these processes. They’re not just “hungry” – they’re obeying their survival instincts.” (4)

Separation Anxiety

From 6 to 8 months, on average, the baby begins to realize that he is a separate individual from his mother. This discovery brings him anguish and panic, so he tends to demand a lot of attention from his mother and may cry more than usual. This phase is completed in a long process that continues to manifest itself in one form or another until two to three years, or even five years, according to other experts.

You have to take the intensity of your feelings seriously. The baby is not “flattering”, “sticky” or “handy”. As the mother is her world and represents her safety, and as the notion of permanence (that is, everything that is out of sight) is not fully established, this anxiety is very accentuated. Most of the nerve connections in the brain are made in childhood, and the way we deal with an infant’s emotions has a profound effect on how these connections will be reflected in the infant’s ability to handle his own emotions as an adult. In other words, early childhood experiences and interaction with the environment are the most critical parts of a child’s brain development. (5)

The separation anxiety system, located in the lower brain, is genetically programmed to be hypersensitive. In the early stages of human evolution it was very dangerous for the baby to be far from its mother. If he didn’t cry to alert his parents of his whereabouts, he wouldn’t be able to survive.

So, when the baby suffers from the absence of his parents, the same areas in his brain are activated as when he suffers physical pain. That is, the language of loss is identical to the language of pain. It makes no sense to alleviate physical pains like a cut on your knee and not comfort emotional pains like separation anguish. But unfortunately, this is what many parents do, because they cannot accept that their child’s emotional pain is as real as their physical one. This is a neurobiological truth that we should all respect.

The development of the frontal lobes naturally inhibits this separation anxiety system.

It is important to understand that the “critical” period of emotional and social development occurs in the child’s first 18 months. The part of the brain that regulates emotions, the amygdala, is formed early according to the experiences the brain receives. The development of emotional attachment, empathy and trust, and all aspects of emotional intelligence provide the foundation for developing other emotional aspects as the child grows. So, emotionally and responsively nurturing the baby is important for the child to learn empathy, happiness, optimism and resilience in life.

Social development, which involves a child’s self-awareness and ability to interact with others, also takes place in stages. For example, sharing toys is something a 2-year-old’s brain isn’t fully developed to do well! So she doesn’t get angry with her child under 2 years old who doesn’t want to share the toys. This social ability is more common and positive in children over 3 years of age.(6)

So, if the mother has to leave her young child to work or for another reason, a lot of affection, conversation, patience and consistency in attitudes are needed so that he can continue to trust her and overcome this period of crisis. It is also very important to make sure that the baby has created an emotional bond with the other caregiver. (7)

Some studies have detected long-term changes in the Hypothalamus-Pituitary-Adrenal axis of the infant brain due to short separations, when the child is in the care of an unknown person. This stress-response system is critical to our ability to cope well with stress in adulthood and is very vulnerable to the adverse effects of premature stress. (8)

Some people justify their decision to let the baby down as a form of “stress inoculation”, which means introducing the baby to moderately stressful situations so that he can learn to deal with tension. Those who claim that babies who cry for a prolonged period of time only experience moderate stress are deceiving themselves as getting rid of the baby or not comforting him (day or night, when they cry or ask for more feeds or cervix than usual) can result in permanent adverse effects on the child’s brain. She may experience panic, which means a significant and dangerous increase in stressful substances in her brain, which can result in an oversensitization of her fear system, which will affect her in her adult life, causing phobias, obsessions or fearful isolation behaviors. (9).

Some practical ideas for reducing Separation Anxiety in your baby are in the previous article on baby’s return to work and sleep such as practicing quick and daily separations, avoiding transfer from lap to lap, and understanding separation anxiety as a positive sign.

Also, at this stage, try to spend as much time as possible with your baby, especially if you work outside the home. Set aside the moments right after the workday reunion to have exclusive dedication to it. Sit comfortably, make eye contact, nurse, interact with your baby. You may be tired and stressed after the long workday, but if you can find some energy to welcome your baby with joy, you will also feel better after a few minutes of meaningful reconnection. Only then think about dinner, bathing and other chores. Consider promoting closeness at bedtime if you suspect your baby has been waking up more at night because of a peak of separation anxiety.

Other changes

Some events, such as the birth of a little brother/daughter, introduction of new foods (see tips for feeding that promotes sleep), the mother’s return to work and entry into day care, travel, illness, separation from parents, friction with classmates, absence of a loved one and others can interfere with the child’s sleep. Be very patient and always offer him security, so gradually the routine can be re-established.

In Short

Developmental leaps and growth peaks are different events and their chronology does not perfectly overlap, although they can occur concurrently.

Growth spikes are about feeding (baby wants to eat more, including at night!) and jumps are about development (baby may want to eat and sleep less).

Separation anxiety is a very critical phase, perhaps the most critical in human development. As babies become aware of the world around them, they begin to form important relationships with the people in their lives, quickly learn that certain people are vital to their happiness and survival, and suffer distress when these people appear and disappear. This has a direct influence on your sleep, especially if the mother returns to work or promotes a weaning (or other type of separation) when the baby is experiencing separation anxiety.

All phenomena are important and can alter the baby’s sleep. But it’s comforting to know that affection, support, love, hugs, empathy and breastfeeding on demand, regardless of the stage they are in, is what the baby needs.

After all, what does “Growth Spurt” mean?
We could translate (not literally) as PEAK OF GROWTH.

baby sucking
It is a phenomenon that occurs in babies and, in which, they request more feeds than usual. These needs usually last from a few days to a week, followed by a return to the smaller feeding pattern.

The mother often feels as if she is not able to produce enough milk for the Baby.

Common periods of these “growth peaks” occur around:

  • 7 – 10 days;
  • 2 – 3 weeks;
  • 4 – 6 weeks;
  • 3 months;
  • Four months;
  • 6 months;
  • 9 months (around)
  • The growth peaks do not stop in the first year. They can occur during the child’s growth, including, for example, adolescence.
  • The more the baby breastfeeds = the more milk it will produce at the breast.
  • Encourage both sides, emptying one side and then moving to the other breast.
  • Trust your production. Withered breasts do not mean less milk.
  • Much of the milk is produced at the time of breastfeeding.
  • It is normal, during peak growth, for the baby to nurse for HOURS at a time.



Babies don’t develop at a steady rate, but at an irregular rate.

baby asking for lap

In the period that immediately precedes a developmental leap, the baby may suddenly feel dispersed to changes in the perceptual and cognitive systems that have not yet been adapted in the organism.

So, in an attempt to readaptation, the baby goes back to base, that is, to the mother, which is reflected in periods of greater emotional need, they ask for more lap, and often affect sleep and appetite.

After a few weeks this difficult phase is overcome, and the baby shows new abilities.

An approximate chronology of crisis periods is:
– 5 weeks / 1 month
– 8 weeks / almost 2 months
– 12 weeks / almost 3 months
– 19 weeks / 4 and a half months
– 26 weeks / 6 months
– 30 weeks / 7 months
– 37 weeks / 8 and a half months
– 46 weeks / almost 11 months
– 55 weeks / almost 13 months
– 64 weeks / almost 15 months
– 75 weeks / 17 months

During this period, the baby is expected to:
– Try to get closer to the MOTHER, that is, his base of everything, because that’s what he knows best;

– Become more needy, needing lap, security and maternal guidance up close;
– Eat badly and sleep worse;
– You can ask to breastfeed more often;
– Start doing things you didn’t do before the crisis such as laughing, sitting, crawling, interacting…
– Demonstrate happiness with the end of the crisis and overcoming the acquired development.

This difficult phase passes, and everything returns to normal, just as naturally as it started.
So, during crises, just have a little patience, affection, complicity… which soon passes…

Source: Reference 1

Editing by Andreia Mortensen and Anna Arena – GVA


1- Hetty van de rijt, Frans Plooij. The Wonder Weeks. How to stimulate your baby”s mental development and help him turn his 8 predictable, great, fussy phases into magical leaps forward. Kiddy World Promotions B.V. 2010.

2- Lopes, R.M. F., Nascimento, R.F.L.; Souza, S. G.; Mallet, L. G.; Argimon, I.I.L. Desenvolvimento Cognitivo e motor de crianças de zero a quinze meses: um estudo de revisão. 2010.

3- Piaget, J. & Inhelder, B. The Psychology of the Child. New York: Basic Books. 1962.

4- Thomas J., The Normal Newborn and Why Breastmilk is Not Just Food. Retirado do website da pediatra e consultora de amamentação. 2010.

5- Gopnik, A., Meltzoff, A.N., and Kuhl, P.K. The Scientist in the Crib: Minds, Brains, and How Children Learn. New York: William Morrow & Co. Inc. 1999

6- Shore, R. Rethinking the Brain: New Insights into Early Development. New York: Families and Work Institute. 1997

7- Margot Sunderland. The Science of Parenting. DK Publishing Inc. 2006.

8- Brummelte S, Grunau RE, Zaidman-Zait A, Weinberg J, Nordstokke D, Cepeda IL. Cortisol levels in relation to maternal interaction and child internalizing behavior in preterm and full-term children at 18 months corrected age. Dev Psychobiol. 2010 Oct 28.

9- Pantley. E. No-Cry Separation Anxiety Solution: Gentle Ways to Make Good-Bye Easy from Six Months to Six Years. McGraw-Hill, 2010.

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