Why Infants Cry During Sleep Training

When I was a new mom, I was exhausted to my core. I’m sure you know the feeling.

I knew my daughter was going to wake up every 3 hours, but I didn’t know those wakings weren’t going to end. Month after month, I waited for her to start sleeping through the night, and it just never happened.

I knew about sleep training, but I wasn’t comfortable with the idea of letting my daughter cry it out. In fact, any crying made my mama-heart hurt. When she went in to get her vaccines, I couldn’t take the screaming and crying — it was literally harder for me than for her.

I felt like I was destined to never sleep again because I knew I wasn’t going to sleep train my daughter. But as you probably realize since I am writing this, I had a change of heart. I did my research, found a method that worked for my family, and my life literally changed in a week.

But the thing is, I didn’t find a magical sleep training method that didn’t result in crying. My daughter still cried, but I was empowered to respond to her needs and know the reason behind the tears. 

Truthfully, there is likely going to be crying with any method chosen to help your child sleep. Why?

The answer is very simple: babies don’t like change. I mean…who does?

Your baby’s brain, like all brains, is built to make connections. In a study done on the development of infant memory (linked below), it was found that as early as 2 months old, your child can remember an event for a day or so. At 3 months old, your baby’s memory lengthens to a week’s time. However, what researchers found is that if an event occurred over and over, the memory would last longer.

How does this research relate to sleep?

By the time most parents and children are ready to sleep train, a baby’s brain has already made connections to the world around them. They have become familiar with the way they fall asleep every single day. And they have done the same routine over and over, forming a strong memory of the way they fall asleep.

In essence, however you’re putting your child to sleep, they have come to expect that.

If you rock them to sleep every night, that’s what they’re going to need in order to fall asleep. They have made the connection that the curvature of their back when you cradle them, the motion of rocking back and forth, your warmth, and your breathing equals falling asleep. 

How These Connections Relate to Crying

Once your child has made their own connections between sleep and the patterns that get them to sleep (rocking, singing, lights, music, etc.), it becomes harder to break those patterns without tears. Crying is your child’s way of communicating, and when they go from swinging in their swing to fall asleep, to being placed in a motionless crib, they realize those patterns that they had become used to are no longer present.

So they cry.

And they’ll continue to cry until they create new connections with sleep.

And that’s what sleep training is: giving your child new connections to associate with sleep.

Instead of falling asleep in the swing and having the association of movement, music, and lights to sleep, they will begin associating the firmness of their mattress, rubbing their face, and pulling on their sleep sack with sleeping.

Crying isn’t bad when we know the cause of it. When your child cries during the sleep training process, they aren’t injured, they aren’t in pain. They are simply communicating with you that they realize something is changing and they don’t like it.

There will be many things in life that your child doesn’t like that benefits them. Eating vegetables, being in a car seat, getting vaccines. These events likely will come with protesting and tears. Changing sleep patterns is no different.

There are many negative effects of a lack of sleep: it impacts your critical thinking, your emotional regulations, and your decision making. Choosing sleep for your whole family is a great thing.

In a study conducted on the impact of sleep training (I’ll like that below, also), researchers found no negative impact on the emotional development of the children, on the connection with their parents, or on their anxiety or stress levels. So while the first few nights of sleep training are difficult, it’s harder on you than on your child. They’ll create new sleep connections within a few days and the crying will end.

I know it’s never easy to hear your child crying. It’s instinctual to respond.

In no way am I advocating against responding to your child’s crying. In fact, there are sleep training methods that promote parent involvement. But sometimes, those methods won’t work for your child depending on their personality.

When you set up a 15-minute call with me, I will be able to determine the best methods for your child. I will always consider your philosophy on parenting, but your child’s needs also have to be considered, and if a method with less parental involvement is needed, I’ll recommend that first.

Getting a good night’s sleep and having a strong connection with your child is possible. Crying during the process isn’t a sign of failure — it’s your child realizing their sleep connections are changing. And in most cases, you’ll be able to respond to your child to reassure them that they’ll be okay.

If you’d like to read more about how your bond with your child doesn’t have to be impacted during the sleep training process, head over to this post and give it a read.


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Rovee-Collier, C. (1999). The Development of Infant Memory. Current Directions in Psychological Science, 8(3), 80. https://doi.org/10.1111/1467-8721.00019

Anna M.H. Price, Melissa Wake, Obioha C. Ukoumunne, Harriet Hiscock. Five-Year Follow-up of Harms and Benefits of Behavioral Infant Sleep Intervention: Randomized Trial. Pediatrics Oct 2012, 130 (4) 643-651; DOI: 10.1542/peds.2011-3467

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I’m Katie

certified pediatric sleep consultant

Fueled by equal parts caffeine and passion, I spend my days helping exhausted mamas get their babies the sleep they need. 

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