Categoría: For parents

The Cry It Out Method: What You Need to Know

Publicado en : May 19, 2024
By Dr. Ana Aznar

Leaving babies to cry it out has been a controversial topic amongst researchers, practitioners, and parents for a very long time. 

I know that this is a very emotive topic. Before we continue, let me tell you that my goal here is to explain the scientific evidence on the “Cry It Out” method so you can decide what to do. I am not addressing personal experiences or judging anyone. 

What is the Cry It Out Method?

The Cry It Out Method (CIO) is a sleep training technique (1) (also known as sleep learning or sleep teaching). The reason to sleep train is to teach babies to fall sleep on their own and stay asleep. 

The Cry It Out method refers to any type of technique that involves leaving a baby to cry until they fall sleep on their own. If the baby wakes during the night parents leave them to cry as well. 

There are three variations of the Cry It Out method:

  • The Extinction method (also known as Unmodified Extinction): The parent leaves the room and does not come back, no matter how long the baby cries for. This method assumes that parents reinforce their child’s crying during the night by responding to it. Parents are required to put their child to sleep and leave them until a pre-determined time in the morning (e.g., 7 am), no matter how much they cry. Many parents (especially those doing it alone) report finding this method extremely stressful (2) therefore gentler methods of extinction have been developed. 

  • The Graduated Extinction method (also known as Controlled Crying, Check and Console, or the Ferber Method): The parent leaves the room and comes in to check on the baby at increasingly pre-determined lengthy intervals (e.g., 1 min, then 2 min, then 3 min, then 15 minutes up to a maximum number of minutes). Visits are short and aimed to encourage the baby to self-soothe. This strategy is usually more acceptable to parents. It has been linked with mothers (3) reporting lower levels of stress and better mood. 

  • The Extinction with Parental Presence method (also known as Camping Out, the Chair Method, or the Fading Method): This is similar to Graduated Extinction, but the parent stays in the room instead of leaving. This method assumes that the presence (4) of the parent helps the baby to self-soothe. Each night the parents moves further away from the baby until they can leave the room leaving the baby settled. 

A very important note: Babies should not be sleep trained, using the Cry It Out Method or any other methods before the age of 6 months (5). Prior to 6 months, babies are not prepared to sleep for long stretches and therefore it doesn’t make sense to sleep train them. For sleep training to work, the baby must be able to self-soothe. 

You may have to wait longer if your baby was born prematurely, with low weight, or with health issues. It is always recommended to talk to your doctor before trying any type of sleep training method.  

Sleep training also implies that the baby is sleeping on their own, which ideally, they shouldn’t do before 6 months because it increases the risk of Sudden Infant Death Syndrome (SIDS) (6).

This doesn’t mean that you must sleep train at 6 months. You can start later, or never!

Does the Cry It Out method work?

Evidence suggests that all three variations of the Cry It Out method work. Babies who have been sleep trained tend to sleep better than babies who have not been trained this way. These effects are still evident six months later (7).

It is, however, important to keep one thing in mind. The aim of the Cry It Out method is to teach the baby to self-soothe. While research shows that babies who are slept trained tend to sleep better, there is no way of knowing if the baby stops crying because they have learnt to self-soothe, they have learnt that no one will come to console them, or because they get tired of crying. 

Will the Cry It Out method hurt my baby? 

Many parents and some researchers worry about the potential damage that letting a baby cry may create. Some researchers (8) are concerned that letting babies cry may cause stress in the infant, be negative for the parent-child attachment, and have a negative effect on the infant’s emotional and mental health. 

To date studies have not found that crying increases infants’ cortisol (9) levels, creates emotional or behavioural issues (10), damages the parent-child attachment (11), nor that it has any short-term or long-term negative effects for the baby (12).

Some studies suggest that the Cry It Out method does not decrease baby crying, or prevent sleep problems in later childhood. It is not entirely clear whether it protects mothers against depression (13). Although it makes sense to assume that when a baby sleeps well, the mother will feel better. 

It is important to note that there are not that many high-quality studies examining the impact of the Cry It Out Method on children. While it’s true that no study has found that letting a baby cry it out has negative effects, at the same time we cannot 100% say that leaving a baby to cry it out is entirely safe for every single child. 

How long does the Cry It Out method take?

It depends. Some children may take a couple of days and others may take weeks. Most strategies take a week or longer to work. They key to make it work is consistency. 

Do I need to sleep train my baby?

Not at all! There are many babies that are not sleep trained and that learn to sleep fine. There is not right way to get your baby to sleep. Do whatever works for your family. Some families choose to co-sleep, others choose to keep the baby in another room and go to them whenever they cry, and others choose to sleep train. There is no right or wrong answer.

The most important thing when considering baby sleep is safety. As parents it’s crucial that we are aware of the guidelines to reduce the risk of accidents and of SIDS. The main guidelines for babies under the age of 6 months are: 

  • Babies must always sleep on their backs, on a flat surface with no soft items around them. 

  • If you choose to co-sleep, make sure the baby cannot fall or suffocate and don’t allow other children or pets in the bed.

  • Do not share a bed if you have been smoking, taken drugs or consumed alcohol. 

  • Never sleep with a baby on a sofa or armchair. 

Are there any other sleep training techniques?

Yes. They all have pros and cons. Some of these techniques are the No Tears method, the Fading Method, or the Pick-up/Put-down method. These methods are considered gentler than then Cry it Out methods. 

All sleep training techniques have something in common…

  • A structured and consistent bedtime routine: no matter if you sleep train your baby or not, a clear bedtime routine is key to help your baby sleep. Everyday your baby should go through the same routine. A good routine looks like this (or similar): bath, dinner, brushing their teeth, relaxing time, and bed. 

  • This bedtime routine must happen every day at the same time. 

My baby does not sleep no matter what I do. Should I hire a sleep consultant?

This is entirely up to you. One important thing to consider is that in many countries (such as the UK), sleep experts or consultants are not regulated. Basically, anyone can consider themselves a sleep expert and provide advice to families. Before you hire anyone, check their credentials, ask about their ethical guidelines, ask to see previous clients’ opinions, and make sure their working style match with your needs and beliefs. For example, don’t hire anyone who will let your baby cry if you don’t want any crying.  

When we consider baby sleep, it’s important to consider cultural influences

There are important cultural differences regarding baby sleep. In some cultures, babies always co-sleep with their parents and even with their siblings, whereas others encourage independent sleep. In general, parents resort to sleep training when they consider that their child has a sleep problem. The most common problems are bedtime resistance, co-sleeping, and night-time awakenings. However, these behaviours are only considered problematic in the Western world (12).

What is the take-home message?

In this article we have explained the latest scientific evidence on the cry it out method. Now that you have the information, it is up to you to decide what you want to do. Whatever you do, don’t feel guilty and ignore other people’s judgments. You are not a better or worse parent whether you co-sleep with your baby or sleep train them.

If you want to learn more about baby sleep, we have three REC Parenting masterclasses discussing: 

Join REC Parenting today to get access to these masterclasses! 

If you are considering hiring a sleep coach, get in touch so we can recommend the one that will suit best your family’s needs. 

If you have any specific questions on baby sleep, drop them here and I will answer it in the REC Parenting weekly Q&A email. 

I hope you have found this information useful.

Much love,


Dr Ana Aznar


(1) Rosier, J. G., & Cassels, T. (2021). From “Crying Expands the Lungs” to “You’re Going to Spoil That Baby”: How the Cry-It-Out Method Became Authoritative Knowledge. Journal of Family Issues, 42(7), 1516-1535.

(2) Etherton, H., Blunden, S., & Hauck, Y. (2016). Discussion of extinction-based behavioral sleep interventions for young children and reasons why parents may find them difficult. Journal of Clinical Sleep Medicine12(11), 1535-1543.

(3) Hall, W.A., Hutton, E., Brant, R.F. et al. (2015). A randomised controlled trial of an intervention for infants’ behavioural sleep problems. BMC Pediatr 15, 181.

(4) Michal Kahn, Michal Juda-Hanael, Efrat Livne-Karp, Liat Tikotzky, Thomas F Anders, Avi Sadeh, Behavioral interventions for pediatric insomnia: one treatment may not fit all, Sleep, Volume 43, Issue 4, April 2020, zsz268,

(5) Whittall, H., Kahn, M., Pillion, M., & Gradisar, M. (2021). Parents matter:  barriers and solutions when implementing behavioural sleep interventions for infant sleep problems. Sleep Medicine, 84, 244-252.

(6) Ball, H. L., & Volpe, L. E. (2013). Sudden Infant Death Syndrome (SIDS) risk reduction and infant sleep location–Moving the discussion forward. Social science & medicine79, 84-91.

(7) Bilgin, A., & Wolke, D. (2020). Parental use of ‘cry it out’in infants: no adverse effects on attachment and behavioural development at 18 months. Journal of Child Psychology and Psychiatry61(11), 1184-1193.

(8) Blunden, S. L., Thompson, K. R., & Dawson, D. (2011). Behavioural sleep treatments and nighttime crying in infants: challenging the status quo. Sleep medicine reviews15(5), 327-334.

(9) Gradisar, M., Jackson, K., Spurrier, N. J., Gibson, J., Whitham, J., Williams, A. S., … & Kennaway, D. J. (2016). Behavioral interventions for infant sleep problems: a randomized controlled trial. Pediatrics137(6).

(10) Price, A. M., Wake, M., Ukoumunne, O. C., & Hiscock, H. (2012). Five-year follow-up of harms and benefits of behavioral infant sleep intervention: randomized trial. Pediatrics130(4), 643-651.

(11) Akdoğan, G. Y. (2018). To intervene or not to intervene: effects of behavioural sleep interventions on infant attachment quality. 

(12) Jenni, O. G., & Werner, H. (2011). Cultural issues in children’s sleep: a model for clinical practice. Pediatric Clinics58(3), 755-763.

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2024-05-25 18:18:00
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