White noise for babies: what should you consider?

The use of white noise for babies is very much in fashion right now. But does it really work? Or is it recommended? Well, NO, I'm sorry, there is currently no scientific evidence that would make us recommend using white noise to get your baby to sleep. What's more, some neurologists advise against it. But as always, we'll explain it to you and offer you the best solution, which is why our midwives at Happymami have written the following post for you: “white noise for babies, better not”. With all the current evidence on white noise and the recommendations of the clinical guidelines on sleep.

What is white noise?

To start understanding all of this, you should know that white noise is the noise produced by combining sounds of the different frequencies audible to humans (ranging from 20 to 20,000 hertz). It is a random noise with the same power spectral density across the entire frequency band.

How does white noise work for sleep?

There are several explanations for the usefulness of white noise as a technique to soothe babies and also to get them to sleep. One of them is that white noise can mask other sounds, so the baby stops hearing himself if he cries and therefore stops crying; another argument is that it is a noise that makes it harder for the baby to wake up when he hears other sudden sounds; other theories suggest that this sound reminds them of their time in the womb, which is why they calm down.

How should white noise be used with a baby?

There is very little information on how effective the use of low-intensity white noise is at promoting relaxation and sleep. Some studies have concluded that white noise can help reduce resistance at bedtime and night-time wakings, although the disturbances tend to return when the emission of noise stops.

The current evidence on the use of white noise is still not rigorous enough to allow conclusions to be drawn about the widespread use of any form of this type of noise for the treatment of paediatric insomnia, of any aetiology and in any age group. Nor is the long-term effect of white noise and/or its variants known, and its potential adverse effects are not completely clear.

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White noise is not recommended to get your baby to sleep

Although some studies seem to show that white noise can help reduce resistance at bedtime and night-time wakings, the disturbances tend to return when the emission of noise stops. There is not enough evidence on efficacy and safety to recommend the use of white noise for the treatment of paediatric insomnia.

What's more, some neurologists advise directly against its use, since using white noise to get your baby to sleep repeatedly can be counterproductive. It can create in your baby an association between sleep and the sound, and can even make your baby unable to sleep if that sound is not present, thus conditioning his sleep.

It is even pointed out that using it at a high volume could affect hearing. This in turn would be counterproductive for your baby's language development, as well as for possible hearing problems.

The best thing is to understand the stages of sleep your baby will go through, and the recommendations that really are proposed by experts in the field.

Stages of sleep

The Clinical Practice Guidelines on Sleep Disorders in Infancy and Adolescence in Primary Care from the Spanish Ministry of Health tells us that throughout life, sleep behaviour varies depending on intrinsic biological cycles and the environment, with changes linked to the development of the central nervous system or to educational, work-related or social factors..., which differ depending on the stage of life, for example.

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In the womb and the first days of life

In the womb, your baby at 30-32 weeks of pregnancy already shows ultradian (lasting less than 24 hours) wake-sleep cycles. And during the first days of life, your baby stays asleep for more than 16 hours a day, spread over several episodes.

This is because in newborns and infants under 3 months of age, active sleep, the precursor of REM sleep, accounts for the largest proportion, reaching up to 60% of total sleep time in the first days of life. It is a kind of sleep characterised by irregular breathing and heartbeat, rapid eye movements, axial muscle atonia and brief muscle contractions accompanied by facial expressions such as smiles and sucking movements.

2 or 3 months of age

At just 2-3 months of age sleep spindles (characteristic of the N2 phase) appear, and it is already possible to distinguish all the stages of sleep. From this age onwards, the hours of sleep, begin to decrease, with changes related to brain maturation, mainly a reduction in the amount of REM sleep.

12 months of age

At 12 months, the average amount of sleep is around 12-13 hours a day and 30% of this time is REM sleep. The following figure shows the percentiles for total hours of sleep from the first months of life to adolescence, in the paediatric population of Zurich.

From 2 years onwards

At 2 years, an average of 13 hours of sleep a day is established, which drops to 10-12 hours at 3-5 years of age, to reach the age of 5, when the child sleeps around 11 hours a day. Between 6-10 years, the central nervous system has largely matured and the average hours of sleep is 10 hours a day.

Functions of sleep

As REM sleep and NREM sleep are physiologically different, their functions are also different. NREM sleep has a restorative function, promotes energy processes and protein synthesis, increases the release of human growth hormone, reduces the stress response (cortisol synthesis) and promotes cell regeneration. REM sleep plays a relevant role in attention and memory processes and in consolidating learning.

Sleep deprivation

Studies on sleep deprivation, total or partial, provide a better understanding of the functions of sleep and its pathophysiology. In adults, lack of sleep causes drowsiness, cognitive deficits and psychiatric symptoms such as mood disorders and irritability. Total deprivation of sleep promotes fatigue and a decline in perceptive, cognitive and psychomotor functions. If this lack of sleep continues, disorientation and hallucinations may occur.

That is why, in children, lack of sleep is also associated with behavioural manifestations such as paradoxical hyperactivity, attention deficits, learning problems and delayed mental development.

Depending on the different types of sleep, depriving a person of them has different consequences. NREM sleep has been linked to greater sleep depth and to the secretion of growth hormone. Chronically reduced sleep of this type causes growth retardation and less tissue regeneration.

Lack of REM sleep causes, in addition to the cognitive and behavioural symptoms described above, difficulties in correct social interaction and a reduced capacity for judgement and decision-making, which in children manifests as impulsivity.

When there are sleep problems, and these exceed a certain intensity or go beyond the person's adaptive capacity, they become pathological, causing significant distress with symptoms affecting the physical, psychological and behavioural spheres.

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Preventive measures

As a human behaviour, sleep can be modified to learn to sleep well. In this way, with proper education from parents and carers from the birth of the baby, most sleep disorders could be prevented.

In children, the key is to establish routines, to give the child what are known as “transitional objects”, which help to associate the environment with sleep and encourage the ability to fall asleep and stay asleep independently.

The essential aspects on which prevention work should be based are as follows

• Although the wake-sleep transition is above all a biological function, it is also modulated by psychosocial factors and the type of education or care children receive, especially from 3-4 months of age.
• Mother-child relationships during the day are important for developing situations or habits related to sleep.
• Because sleep in our sociocultural environment traditionally involves the separation of the carer from the child, progressive separations during the day should be assessed according to family beliefs about the care to be given to children, the style of education and the type of attachment.
• Whether the different ways of putting children to bed (alone, sharing a room with siblings or with parents, sharing a bed with parents...) are beneficial or harmful at a given age does not depend solely on the location and the way in which sleep develops, but fundamentally on the social and psychological meaning that the model chosen by the parents (not forced by the child's behaviour) has for relationships within the family.
• To educate in any area, in general, there are no good or bad systems, only different ones. The best system is the one that fits most harmoniously with each family unit and follows the dominant cultural criteria

Advice to include in preventive measures for sleep problems

Under two months

• The newborn sleeps a lot, but cannot do so continuously. Every 3-4 hours he wakes up. He needs to feed, to be changed and to be spoken to.
• After feeding he begins what we call “active sleep”: he moves his eyes, pulls faces, breathes irregularly, makes the occasional whimper and makes small movements with his limbs. Although the child may seem restless, this type of sleep is completely normal and must not be interrupted under any circumstances.
• If parents or the people caring for the baby do not know about this, it is very likely that they will touch him, pick him up or rock him, thereby disrupting his normal sleep and hindering his maturation. After about 30-40 minutes in this state, the baby enters deeper sleep, which we call “quiet sleep”. He is completely relaxed and breathes softly and deeply.

Between 2-5 months

• A good quality sleep during the day will improve night-time sleep.
• Before each period of sleep it is a good idea to soothe the baby.
• Movements for a few minutes, face-to-face contact and gentle words should help to soothe him (or reduce his level of arousal), but not to get him to sleep.

Between 5-12 months

• During the first 8 months it can be usual and normal for the baby to wake up at night.
• From 5 months of age the baby picks up all the sensations that adults transmit to him. If the parents are calm and speak to him sweetly, the baby will pick up on this feeling and respond in the same way. On the other hand, if they hesitate, are restless or constantly change routines, the baby will become insecure and show restlessness.

From 12 months onwards

• The child can begin to understand that he is being taught to sleep independently.

Assessment of sleep by a healthcare professional

If you have any doubts about whether your baby/child has any sleep problem, your primary care doctor can assess it. For the interview with parents/family members/patients when sleep disorders are suspected, there are a series of questions that can be used as a guide to help healthcare professionals detect sleep disorders and make a differential diagnosis of other sleep problems or other disorders

Key questions that may raise suspicion of sleep disorders

DURING THE DAY, does he…:

• poor school performance?
• hyperactivity?
• behavioural problems, aggression?
• frequent accidents?
• growing pains?
• morning headaches?
• delayed growth and weight gain?
• excessive daytime sleepiness (in > 5 years)?
• does his behaviour improve if he sleeps more?

DURING THE NIGHT, does he…:

• frequent wakings (3-5 wakings/night, more than 3 nights/week (in > 1 year)?
• does he take more than half an hour to fall asleep? Does he cry?
• night-time snoring?
• breathing pauses?
• mouth breathing?
• difficulty waking up in the morning?
• excessive irritability on waking?

Conclusion: white noise for babies, better not

As mums and midwives we understand you perfectly: that moment when the baby has not let you sleep for several days, and you try using white noise and he falls asleep. But in the end, we must listen to science and its recommendations. Before it gets to the point where your baby cannot sleep, and you have to resort to white noise, try following the recommendations of the clinical guidelines to encourage the correct sleep of your baby. You're doing a great job, and in the end these nights of insomnia will be nothing more than anecdotal.