Looking for answers about the Cry-It-Out (CIO) sleep training method? You’re not alone. Many exhausted parents explore sleep training in hopes of helping their baby (and themselves!) get better rest. But is CIO safe? And if so, when and how should it be used? Let’s take a closer look at what extinction sleep training (CIO) really is, when it works, and why gentler sleep strategies might be the path your family needs.
What is the Cry-It-Out Method (Extinction Sleep Training)?
The Cry-It-Out (CIO) method is a sleep training approach where a baby is put to bed while still awake and then allowed to cry for a certain period without immediate comfort. The goal? Teach babies to self-soothe and fall asleep independently.
There are two primary types of CIO:
- Extinction Method: Parents put the baby down and don’t return—even if the baby cries.
- Ferber Method (Graduated Extinction): Parents return at timed intervals to check in and reassure, without picking the baby up.
What do I not recommend? Full extinction—where a parent leaves and doesn’t check in at all. This method, in my view, is unnecessarily harsh and doesn’t reflect what we know about infant development and emotional attachment.
Instead, I advocate for responsive, proven alternatives like the Sleep Lady Shuffle, where a parent stays near the baby and gradually reduces intervention over time.
Is the Cry-It-Out Method Safe?
The safety of CIO depends largely on how and when it’s used. While some studies show no long-term harm, others raise concerns around emotional stress and attachment. Let’s look at both sides.
Research That Supports CIO
- Attachment and Development: A 2020 study found no negative effects on babies’ behavior or attachment at 18 months, even with occasional use of CIO.
- Improved Sleep: Another study found that babies subjected to CIO slept better and experienced less nighttime crying over time (Giesbrecht et al., 2020).
- Stress Reduction: Research from 1988 (Rickert & Johnson) showed babies cried less overall within a few days, suggesting improved self-soothing.
- Parental Well-Being: Better baby sleep also improves parental mental health, including reduced stress and postpartum depression (Moore et al., 2008).
CIO Concerns and Criticism
Not every expert is on board with CIO. Criticism centers around stress, emotional health, and potential long-term impacts.
- Attachment Worries: Critics argue that some studies (e.g., Davis, 2021) don’t adequately account for impacts on security and regulation of stress.
- Does CIO Teach Self-Soothing? Some research (Rosier et al., 2020) suggests CIO might simply teach babies not to expect help, rather than fostering real self-soothing.
- Parental Stress: Many caregivers find CIO emotionally distressing—making consistency hard to maintain.
- Cortisol Concerns: Long, unsoothed crying may increase stress hormone levels (Douglas & Hill, 2013).
The good news? There’s a middle ground.
My Take on CIO: A Balanced Perspective
- CIO isn’t inherently harmful—when applied correctly, evidence doesn’t show long-term damage.
- Full extinction isn’t necessary—kinder approaches are just as effective.
- Consistency matters—inconsistent implementation can make things worse.
- Your baby is unique—choose what suits your child’s temperament and your parenting style.
There’s no need to choose between “no crying” and “crying it out cold turkey.” Approaches such as the Sleep Lady Shuffle offer a path to independent sleep while preserving emotional connection.
What Age Is Appropriate for Cry It Out?
⚠️Generally, babies aren’t developmentally ready for CIO until around 6 months old. Before that, sleep should center on comfort and habit-building—not intense training.
⚠️ At 4–5 months, gentle sleep shaping may be appropriate—but avoid full CIO. Focus on baby-led cues and short separation periods if attempting gradual changes.
Should You Let a 3-Month-Old Cry It Out?
No, absolutely not. At 3 months, babies are still establishing sleep rhythms and need responsive care. Crying is their primary communication—and they still need frequent feeding and snuggling.
What About Newborns?
Never use CIO with a newborn (0–4 months). Tiny babies need love on demand—so focus instead on:
- Building a consistent bedtime routine
- Using age-appropriate wake windows to avoid overtiredness
- Practicing “drowsy but awake” methods for early self-soothing
How Long to Let a Baby Cry It Out?
- Ferber (Graduated Extinction): Use progressive intervals—5 minutes, then 10, then 15.
- Full CIO: No recommended maximum—not advised by me. Crying should never continue unchecked beyond 90 minutes. That’s a sign to reconsider your approach.
CIO for Naps: A Different Game
- Babies need shorter crying intervals for naps—30 minutes max before adjusting.
- If baby cries longer than 30 minutes, reevaluate your method, wake windows, or sleep environment.
- Still not working after a few days? Try a modified approach like remaining in the room or using a nap-specific Sleep Lady Shuffle.
Safety and Ethics: What to Consider
Is CIO harmful? Not when used correctly and when responsive alternatives are considered. But it isn’t one-size-fits-all. Excessively long, unsoothed crying is not something I endorse.
Why is CIO controversial? Many parents and professionals are concerned about the emotional distress involved. Non-cry solutions can be equally effective—for example, my gentle sleep coaching methods.
Controlled Crying vs. CIO: Know the Difference
Controlled Crying (e.g., Ferber): Check and reassure periodically.
Extinction CIO: No checks or comforting during tears (not recommended).
What About Regressions? Avoid CIO
Do not use CIO during sleep regressions—like the ones around 4, 8, or 12 months. Babies are going through developmental leaps and need more support.
When sleep falls apart, first rebuild routines and offer extra comfort—don’t leap into CIO.
Final Thoughts: CIO Isn’t the Only Path
CIO can work—but it’s not the only method. If it doesn’t feel right, you have options. Gentle, consistent approaches like the Sleep Lady Shuffle help your baby sleep without unnecessary tears.