What Is Cry It Out?
Cry It Out (CIO), also called full extinction, is the most direct approach to sleep training. You complete your bedtime routine, put your baby down awake, say goodnight, and leave the room without returning until morning (or the next scheduled feed). There are no timed check-ins.
While it sounds harsh, research consistently shows that CIO produces the fastest results and does not cause long-term emotional harm. A landmark 2016 study in Pediatrics (Gradisar et al.) found no differences in stress levels, emotional health, or parent-child attachment at age 5 between children who had CIO and those who didn't.
When Is CIO Appropriate?
- Your baby is at least 6 months old and medically healthy.
- Your baby does not have reflux, breathing issues, or other conditions requiring nighttime attention.
- Your pediatrician has confirmed your baby can go through the night without a feeding (or you have a clear plan for scheduled feeds).
- Gentler methods have been tried and haven't worked, or you prefer a faster approach.
- Both parents are on board and committed to consistency.
What to Expect
Night 1 typically involves 45-90 minutes of crying before your baby falls asleep. Night 2 usually drops to 20-45 minutes. By night 3, most babies are falling asleep within 10-20 minutes. CIO often produces the fastest results of any method because there is no intermittent reinforcement from check-ins.
The reason CIO can work faster than Ferber is that check-ins can sometimes escalate crying by reminding the baby that you're nearby but not picking them up. Without check-ins, many babies settle faster.
Safety Considerations
- Ensure the crib meets current safety standards with a firm, flat mattress and nothing else inside.
- Use a video monitor so you can observe your baby without entering the room.
- Set a firm plan for scheduled night feeds if your baby still needs them. CIO applies to non-feeding wakings.
- If your baby is sick, delay starting until they are fully recovered.
- Trust your instincts. If something feels wrong or your baby's cry sounds different from a protest cry, check on them.
CIO is not recommended for babies under 6 months. Younger babies may still have legitimate nighttime needs that require a caregiver's response.
Tips for Parents
The hardest part of CIO is the parent experience, not the baby's. Have a plan for how you'll cope on night 1: leave the house and let the monitoring parent handle it, use noise-canceling headphones, or sit outside with a friend. Remind yourselves that short-term discomfort leads to better sleep for the whole family.
See our comprehensive guide: /sleep-training
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