Does Sleep Training Really ‘Do No Harm’?
Unpacking the Research, the Claims, and the Complexities of Parenting Choices
I hope this blog post resonates with fellow moms and anyone navigating the challenges of sleep, parenting, and motherhood. If you find it helpful, feel free to share it with other parents or anyone who might need support. My writing is supported by you, my readers, and if you’re able to subscribe, your support is always appreciated.
It’s late, and the house is finally quiet—except for the thoughts swirling in your mind. Earlier, you stumbled across a post claiming, “Sleep training does no harm.” After weeks of struggling with night wakings and relentless exhaustion, the words felt like a lifeline. But now, as you replay them in your head, doubts begin to creep in. Is this really the full picture?
Navigating sleep challenges can be overwhelming. Parenting often feels like a barrage of conflicting advice, each claiming to hold the magic answer. Amid exhaustion, the promise of certainty—like the reassurance that sleep training causes no harm—can feel like a welcome relief. But what does “no harm” truly mean? Is it enough to simply avoid harm, or should we aim to nurture connection, emotional resilience, and secure attachment?
This blog isn’t here to judge or criticise your parenting choices. It’s a compassionate exploration of what the claim “sleep training does no harm” really means—and, crucially, what it doesn’t. By examining the evidence, considering its limitations, and reflecting on what we know about child development, attachment, and neuroscience, this space aims to empower you with nuanced, evidence-based information.
Parenting is a journey of learning and growth, not perfection. Every parent makes decisions with love and the best tools they have at the time. Together, let’s take a deeper look at this claim and consider how we can move beyond the binary of “right” or “wrong” toward choices that align with our values and our children’s unique needs.
Unpacking the Claim "Sleep Training Does No Harm"
The Oversimplified Claim
The phrase “sleep training does no harm” is often presented as a reassuring blanket statement, but it sets an incredibly low bar. As parents, our goals often go far beyond avoiding harm—we aim to nurture connection, emotional resilience, and secure attachment. Reducing parenting choices to whether they “cause harm” risks overlooking the richer, more nuanced ways we can support our children’s development.
It’s easy to see why this claim has gained traction. It provides comfort to parents navigating the complexities of sleep challenges, a time when exhaustion can leave us feeling desperate for solutions. However, the truth is that this assertion is based on limited research with significant flaws. A closer look reveals that these studies fall short of proving what they claim.
A Closer Look at the Research
Several key studies are often cited to support the idea that sleep training does no harm, including those by Hiscock, Price, and Gradisar. While these studies are well-known, they have significant limitations that undermine their conclusions.
A Note to Readers: This section delves deeply into the research often cited to support the claim that sleep training does no harm. While it may feel heavy, sharing this level of detail is vital to offer a balanced, accurate understanding of the studies behind these claims. By unpacking these findings, I hope to empower you with information to make decisions that align with your child’s needs and your family values.
The Hiscock Study (2002)
This Australian study sought to examine the long-term mental health outcomes for mothers and infants following graduated extinction (cry-it-out). The researchers recruited 328 mother-infant pairs when the infants were seven months old and randomised them into two groups: one received usual care, and the other followed a graduated extinction program. The key findings were:
Fewer mothers in the graduated extinction group had significant depressive symptoms when their child was two years old (15% vs. 26% in the control group).
Crucially, there was no statistically significant difference in sleep outcomes between the intervention and control groups.
Critical Flaws:
Lack of Significant Sleep Improvement: Despite being a sleep intervention study, no notable differences in sleep were observed between the two groups. This undermines the argument that sleep training effectively addresses sleep challenges.
Maternal Mental Health Gains Were Limited: While fewer mothers in the intervention group reported depressive symptoms, 15% still experienced significant depression—suggesting that sleep training alone is not a comprehensive solution for maternal well-being.
The Price Study (2012)
This follow-up to the Hiscock study aimed to determine whether graduated extinction had long-term negative effects on children, particularly concerning stress regulation and attachment. Researchers assessed cortisol levels (known as the ‘stress hormone’) when the children were six years old.
Critical Flaws:
High Attrition Rates: Almost half (46%) of the original sample refused to participate in the follow-up, raising concerns about bias.
No Baseline Cortisol Data: Cortisol levels were not measured before the intervention, so there’s no way to determine whether stress levels changed as a result of sleep training.
Timing of Cortisol Samples: Samples were taken years after the intervention, with no data immediately before, during, or after sleep training to capture its immediate effects.
Underrepresented Populations: The study excluded non-English speakers and underrepresented Black and ethnic minority groups, limiting its generalisability.
Ambiguous Cortisol Results: Researchers vaguely concluded that cortisol levels were “similar” between groups without providing robust data to substantiate this claim.
Given these limitations, the assertion that graduated extinction has no long-term negative effects lacks validity. The study’s design does not allow for such a sweeping conclusion.
The Gradisar Study (2016)
This small-scale study examined the effects of graduated extinction, fading, and supportive care on infant sleep, maternal stress, and attachment. Researchers measured cortisol levels before and 12 months after the intervention and used the Strange Situation Test to assess attachment.
Critical Flaws:
Minimal Sleep Improvement: The study claimed a significant reduction in nighttime wake-ups for the graduated extinction group, but the actual decrease was modest:
Graduated extinction: From 2.7 to 1.4 wake-ups per night (-1.3 wake-ups).
Control group: From 2.6 to 2.1 wake-ups (-0.5 wake-ups).
High Rates of Insecure Attachment: The data revealed concerning attachment outcomes:
46% of the graduated extinction group were insecurely attached.
39% of the control group were insecurely attached. These figures exceed the general population prevalence of insecure attachment (30%), raising questions about the study’s sample and findings.
Inappropriate Use of Attachment Measures: The Strange Situation Test is validated for children aged 12-20 months but was applied to children up to 28 months in this study, making the attachment findings unreliable.
Underpowered Sample Size: Each group had fewer than the recommended 21 participants, rendering the findings statistically weak.
What does this mean?
The claim that “sleep training does no harm” is often presented as definitive, yet the research frequently cited to support this argument has been critiqued for years.
Furthermore, critical gaps remain in our understanding of key questions, such as:
The dose response of crying: How much crying is too much?
The role of individual differences: A child’s resilience and attachment security likely affect their ability to tolerate controlled crying, yet assessing these aspects is outside the scope of most sleep practitioners.
Without robust evidence, it is impossible to assert with confidence that controlled crying or other extinction-based methods are universally harmless or effective.
Experts have repeatedly raised concerns about the validity of these studies and their ability to definitively prove the absence of harm. By relying on outdated or overly simplistic interpretations of this research, we risk perpetuating a narrative that doesn’t fully reflect the complexity of sleep, emotional development, or the nuanced needs of children and families.
Lessons from History: The Smoking Analogy
Decades ago, early studies suggested that smoking was harmless. At the time, these findings were widely accepted and even used in marketing campaigns. It took years of better-designed research to uncover the profound harm smoking causes. This serves as a reminder that early claims in science are not always definitive. Just because a study hasn’t found harm doesn’t mean harm doesn’t exist—it may simply mean we haven’t yet looked closely enough or asked the right questions.
A Call for Nuance
Parents deserve better than a simplified narrative. They deserve evidence-based, nuanced information that acknowledges the broader dynamics at play in sleep challenges. Instead of focusing on whether something causes harm, we can shift the conversation toward evidence-based practices that actively support attachment, emotional regulation, and long-term well-being—for both children and their parents.
By challenging this oversimplified claim, we can shift the conversation toward approaches that not only avoid harm but actively nurture emotional resilience, secure attachment, and relational well-being.
The Complexity of Sleep and Emotional Development
Sleep: A Multifaceted Experience
Sleep challenges are rarely just about sleep. They’re shaped by a complex web of factors, including family dynamics, temperament, birth history, attachment, and parental well-being. For instance, a baby who had a challenging birth or a toddler navigating big emotional transitions might struggle with sleep in ways that reflect these underlying experiences.
Viewing sleep through a narrow lens—focused solely on schedules or techniques—can overlook these deeper influences. By taking a step back and seeing the bigger picture, we can begin to address these challenges in ways that nurture the whole child and family, rather than trying to "fix" sleep as an isolated behaviour.
The Role of Co-Regulation in Sleep
Sleep is not just a solitary act of shutting down for the night; it’s an emotional and relational experience for children. When sleep struggles arise, they often highlight a child’s need for connection, comfort, and reassurance. Co-regulation plays a pivotal role in addressing these needs and fostering healthy emotional development.
What Is Co-Regulation?
Co-regulation is the process by which caregivers provide emotional stability and calm to help a child navigate overwhelming feelings. This isn’t about "fixing" emotions or stopping tears—it’s about being present with your child in their distress, showing them they are not alone. Through co-regulation, caregivers create a sense of safety that helps children move from a state of dysregulation to calm.
Sleep as a Relational Process
For young children, sleep is deeply relational. Nighttime wake-ups often reflect a child’s developmentally appropriate need for connection and reassurance rather than a desire to disrupt or resist sleep. When children cry at night, they’re asking fundamental questions: Am I safe? Will you be there for me? These moments offer caregivers an opportunity to provide co-regulation and reinforce a sense of trust and security.
Sleep training methods that emphasise ignoring these cues or extinguishing crying may achieve outward calm, but research suggests this calmness is not necessarily a sign of true emotional regulation.
Co-Regulation and Emotional Development
Neuroscience tells us that a child’s developing brain thrives in environments of responsive caregiving. During moments of distress, the stress-response system activates, releasing cortisol to help the body cope. While short-term cortisol spikes are a normal part of development, prolonged or unresolved stress can overactivate the stress-response system, potentially affecting emotional regulation and resilience.
When caregivers engage in co-regulation—by holding, soothing, or simply being present—they help buffer this stress, allowing the child’s nervous system to reset. These moments don’t just resolve immediate distress; they shape how a child’s brain processes and responds to emotions over time.
Conversely, ignoring distress signals, as some sleep training methods advocate, may suppress outward crying but leave the underlying emotional need unmet. Research into infant mental health suggests that leaving babies alone to cry induces high levels of stress, as evidenced by elevated cortisol levels and a behavioural response known as ‘learned helplessness’ (Ronald de Kloet, 2004; Waters et al., 2000; Middlemiss et al., 2012). In these scenarios, a baby may stop signaling not because they have learned to self-soothe, but because they have resigned themselves to the absence of support. Elevated cortisol levels in infants left to cry alone are well-documented (Middlemiss et al., 2012), and there is no evidence that controlled crying effectively reduces these stress responses over time.
While studies claiming “no harm” argue that children adapt to sleep training without long-term consequences, they often fail to explore the relational and developmental nuances of this adaptation. The absence of crying doesn’t necessarily mean the absence of stress or unmet needs.
Addressing Misconceptions About Dependency
One common misconception about responsive caregiving is that it fosters dependency. In reality, the opposite is true. When children experience consistent co-regulation, they internalise a sense of safety and trust, which becomes the foundation for growing independence. A child who knows their caregiver will respond to their needs is more likely to explore their environment and develop confidence.
In the context of sleep, this means that responding to nighttime wake-ups with empathy and care doesn’t create "bad habits"—it nurtures emotional security. Over time, this security enables children to learn to self-soothe and sleep more independently, not because they’ve been taught to ignore their emotions, but because they feel safe in their environment.
For more insights into fostering connection and addressing sleep challenges, check out my recent blog posts on the role of distraction in responding to children’s needs and responsive parenting.
Compassion for Parents Navigating Nighttime Challenges
Responding to night wakings is emotionally and physically demanding, especially during seasons of sleep deprivation. It’s normal to feel stretched thin or overwhelmed by the relentless demands of caregiving. But it’s important to remember: perfection isn’t required. Every moment of responsiveness, no matter how small, contributes to your child’s emotional security.
Co-regulation doesn’t mean you have to solve every problem instantly or suppress your own exhaustion. It’s about showing up with empathy and presence, even in imperfect moments. These efforts, however small they may feel, have a profound impact on your child’s sense of safety and trust.
Balancing Co-Regulation with Parental Well-Being
While co-regulation is invaluable, it’s equally important to care for yourself. Sharing nighttime responsibilities with a partner or trusted caregiver, creating calming routines that work for your family, or simply finding moments of rest during the day can help you recharge. Prioritising your own well-being isn’t just self-care; it’s a vital part of supporting your child effectively.
The Risks of Ignoring Emotional Cues
Parenting is a balancing act, especially when it comes to nighttime care. Exhaustion, societal pressures, and conflicting advice often push parents toward solutions that promise results. However, when sleep training methods involve ignoring a child’s emotional cues—like crying or signaling for comfort—it’s important to consider the potential short- and long-term consequences.
Short-Term Impacts: Suppressing Signals, Not Needs
When a baby or young child cries during the night, they’re signaling a need—whether for comfort, safety, reassurance, or a response to an unmet physiological need. Ignoring these signals, as some sleep training methods advocate, may result in behavioural extinction (i.e., the cessation of crying), but this doesn’t mean the underlying need has been met.
As mentioned previously, research suggests that outward calmness achieved during sleep training is often mistaken for emotional regulation. Instead, this behaviour can indicate a child has stopped signaling because their cues were consistently ignored. The emotional need doesn’t disappear; it’s simply left unaddressed. Over time, this could leave children feeling uncertain about whether their needs will be met, even as they outwardly comply with expectations.
Long-Term Implications: The Relational Cost of Ignored Cues
Attachment is built on trust—the trust that a caregiver will consistently respond to a child’s emotional and physical needs. When distress signals are consistently unmet, it can influence a child’s internal working model of relationships. Over time, this may shape their beliefs about whether they can rely on others during moments of vulnerability and whether their feelings are valid.
Ignoring emotional cues during critical periods of attachment development may inadvertently affect how a child learns to navigate emotions, seek support, and trust in their relationships. These are subtle, relational consequences that can be missed in studies focused on measurable, short-term outcomes.
That said, it’s essential to avoid catastrophising. Secure attachment is built over time through consistent, responsive caregiving—not perfection. Occasional missed cues or moments of frustration won’t harm the bond between you and your child. It’s the overall pattern of responsiveness that fosters emotional security.
Why "No Harm" Is Not Enough
The Complexity of Harm
The absence of measurable harm in a study doesn’t mean a practice is optimal or beneficial. Parenting choices, especially around sleep, aren’t just about avoiding harm—they’re about fostering connection, trust, and emotional resilience. To truly understand whether a practice supports a child’s development, we must look beyond surface-level claims of “no harm” and consider the broader relational and developmental impacts.
Studies claiming “no harm” often measure narrow outcomes, such as cortisol levels years later, without accounting for the nuances of attachment, co-regulation, or emotional security. For example, the long-term effects of suppressing a child’s distress during sleep training may not appear in a simple cortisol reading but could influence how a child learns to seek and receive comfort over time. These studies often miss the bigger picture: does this approach nurture the secure relationships that children need to thrive?
Parents make decisions with love at the center, often under immense pressure and with limited resources. Sleep deprivation, conflicting advice, and cultural expectations can make these choices even harder. It’s vital to acknowledge that parents act with the best information they have at any given time.
At the same time, as new evidence and understanding emerge, it’s natural and commendable to adapt. Just as we’ve seen shifts in recommendations for everything from car seat safety to feeding practices, evolving knowledge allows us to make better-informed decisions. This isn’t about judging past choices but about recognising the value of growth and embracing tools that align with our parenting goals.
Empowerment Through Knowledge
Instead of asking “does it harm?” we can ask “does it help?” Specifically:
Does it nurture attachment and trust between parent and child?
Does it support emotional security and resilience in the long term?
Does it align with my values as a parent?
When we reframe the conversation in this way, we move beyond simply avoiding harm and toward creating meaningful connections with our children. Instead of asking whether a practice causes harm, we can explore whether it actively supports our long-term parenting goals. Parenting is about more than just getting through the night—it’s about fostering relationships that will shape who our children become.
A Holistic Approach to Sleep Support
Connection-Focused Practices
Sleep isn’t just a behaviour to manage—it’s a relational experience. By responding to your child’s nighttime needs with empathy, you’re not just helping them sleep; you’re building trust and emotional security that will last a lifetime. Nighttime care offers a unique opportunity to deepen your bond and nurture resilience through connection and co-regulation.
When your child wakes during the night, they’re not trying to manipulate or inconvenience you. They’re seeking reassurance and comfort—signs of the strong connection they feel with you. Trusting in this relationship, and in your ability to meet their needs, can transform how you approach these moments. By focusing on connection rather than control, you’re not just addressing immediate sleep challenges; you’re laying a foundation for emotional resilience that will support your child for years to come.
Shifting the Conversation
A more sensible and compassionate approach to sleep challenges is to recommend techniques that avoid extinction and embrace responsive caregiving. This doesn’t mean adhering to a single method or philosophy but rather adopting a flexible, connection-focused approach that aligns with the child’s and family’s unique needs.
Parenting is a journey marked by love, growth, and learning. Parenting decisions deserve to be informed by robust, up-to-date evidence that reflects the complexity of child development and attachment, not outdated research with significant limitations.
By shifting the conversation away from “no harm” and toward practices that actively nurture connection, trust, and emotional resilience, we can empower parents to make decisions that truly align with their values and their child’s needs.
If this perspective resonates with you, I encourage you to explore my Holistic Sleep Series, a free email series exclusively available to my mailing list subscribers. It is designed to provide compassionate, research-based guidance for parents navigating sleep challenges (it launches on Monday 25th November!). Over the course of a week, you’ll receive actionable tips, insights into attachment and co-regulation, and practical strategies for balancing your child’s needs with your own. Sign up to my mailing list here if you would like to join us.
For more support, check out my other blog posts on topics like responsive parenting, co-regulation, and rethinking distraction. Together, we can create a space where your child feels secure, supported, and loved—and where you feel empowered to thrive as a parent.