Four months is the earliest age most pediatricians consider appropriate for sleep training. At this stage, your baby’s sleep cycles are shifting from predominantly deep sleep to a more adult-like pattern that cycles between deep and light phases. That shift is exactly why many babies start waking more often around this age, and it’s also what makes them ready to learn how to fall back asleep on their own.
Why 4 Months Is a Turning Point
Newborns spend most of their sleep time in deep sleep, which is why they can seem to sleep through anything. Around 4 months, the brain begins cycling through lighter sleep stages, just like adults do. This reorganization is a permanent, healthy change, but it means your baby now briefly surfaces between sleep cycles and may not know how to drift back off without help.
This is also around the time the circadian rhythm, your baby’s internal clock for day and night, starts functioning. That biological readiness is what makes sleep training possible. Before this point, babies simply don’t have the neurological wiring to learn the skill of self-settling. Some babies are ready a bit earlier, and some do better closer to 6 months. If your baby was premature, use their adjusted age as the benchmark.
Signs Your Baby Is Ready
Readiness isn’t just about age. Look for these behaviors: your baby can calm down after brief fussing without being picked up, they’ve started bringing their hands to their mouth or turning their head to get comfortable, and they no longer need to eat every two to three hours overnight. By 4 months, many babies can go five or more hours between nighttime feeds, and most healthy 4-month-olds don’t need more than one or two feeds per night. If your baby is still waking to eat more than twice, that’s worth addressing alongside (or before) sleep training.
Before You Start: The Setup
Sleep training works best when the environment and routine are consistent. A few things to lock in first:
- Room temperature. Keep the room between 68 and 78°F. A fan on low helps circulate air and provides gentle white noise.
- Safe sleep surface. Use a firm, flat crib mattress that fits snugly in the crib with no gaps. No pillows, blankets, bumpers, or stuffed animals. The mattress shouldn’t indent when your baby lies on it.
- Room sharing, not bed sharing. The American Academy of Pediatrics recommends keeping your baby’s crib in your room for at least the first six months. This alone can reduce the risk of SIDS by as much as 50%. But your baby should be in their own sleep space, not in your bed.
- A predictable bedtime routine. Bath, feeding, a short book or song, then into the crib. The same sequence every night teaches your baby that sleep is coming. Move the feeding earlier in the routine so it’s not the last step before the crib. You don’t want your baby associating falling asleep with eating.
- The right bedtime. Pick a time when your baby typically falls asleep within 15 to 20 minutes of lights out. Putting them down too early leads to long crying that isn’t productive, and too late means an overtired baby who struggles even more.
The Graduated Check-In Method (Ferber)
This is the most widely recommended approach for parents who want structure but aren’t comfortable with leaving their baby to cry indefinitely. The idea is simple: you put your baby down drowsy but awake, leave the room, and return at gradually increasing intervals to briefly reassure them.
On the first night, wait 3 minutes before your first check-in. Then wait 5 minutes before the next one, then 10 minutes for every check after that. On night two, start at 5 minutes, then 10, then 12. By night three, the intervals are 10, 12, and 15 minutes. Each check-in should be brief, about a minute. You can speak softly or give a gentle pat, but don’t pick your baby up or stay until they’re asleep. The goal is to show them you’re still there, not to do the work of falling asleep for them.
This method typically takes 7 to 10 days to produce consistent results. The first two or three nights are usually the hardest. Many parents see a dramatic drop in crying by night four or five.
The Pick Up, Put Down Method
If graduated check-ins feel too hands-off, this gentler approach keeps you more involved. You put your baby in the crib awake, leave the room, and when they cry, you go in and pick them up to soothe them. The key rule: set them back down the moment their eyelids start to droop. You’re comforting them, but you’re not letting them fall asleep in your arms.
If they cry the second their head touches the crib, you pick them up again and repeat the whole cycle. This can mean dozens of repetitions in a single night, especially early on. It requires patience and physical stamina, but it’s a good fit for parents who find it hard to listen to sustained crying. Expect this approach to take up to four weeks before you see consistent independent sleep.
Full Extinction (Cry It Out)
This is the most direct approach: put your baby down drowsy but awake, say goodnight, and leave the room. You don’t go back in unless you’re genuinely worried your baby is sick or hurt. The crying can be intense on the first night or two, sometimes lasting 45 minutes to an hour or more.
A few practical tips if you choose this route. Lower the crib mattress to its lowest setting so there’s no chance of climbing out. If you’ve been bed sharing, transition your baby to their own sleep space for a few days before starting. And give yourself permission to mute the monitor. Unless you live in a very large home, you’ll hear the crying through the walls. Watching it on a screen only makes it harder to stay consistent.
Full extinction tends to work the fastest, often within three to four days. It’s not more harmful than other methods. The speed comes from the consistency: because you aren’t going back in, your baby doesn’t get mixed signals about whether crying will bring you back.
Handling Night Wakings During Training
Whatever method you choose at bedtime, apply the same approach to middle-of-the-night wakings. If you’re using graduated check-ins at bedtime but then picking your baby up and rocking them at 2 a.m., you’re sending conflicting messages that will slow the process down considerably.
The exception is legitimate hunger. At 4 months, one or two overnight feeds are still normal and fine. If your baby wakes and it’s been five or more hours since their last feed, go ahead and feed them. Keep the lights dim, the interaction minimal, and put them back in the crib awake when you’re done. The goal is to preserve night feeds as a quiet, boring biological need rather than a social event that rewards waking up.
What to Expect in the First Week
Night one is almost always the worst regardless of method. Your baby doesn’t understand what’s changed, and their only tool for communicating displeasure is crying. This is normal, expected, and not a sign that something is wrong or that you’ve chosen the wrong method.
Nights two and three often involve a similar amount of crying, sometimes even a slight increase on night two (sometimes called an “extinction burst,” where the baby tries harder before giving up the old pattern). By nights four through seven, most families using check-in or extinction methods see a noticeable decline. Your baby may still fuss for a few minutes at bedtime, but the prolonged crying typically drops off sharply.
For gentler methods like pick up, put down, the timeline is slower and more gradual. You might not see a clear turning point until the second or third week. Progress can feel invisible day to day but becomes obvious when you compare week one to week three.
Common Setbacks and How to Handle Them
Illness, travel, teething, and growth spurts can all temporarily undo progress. This doesn’t mean sleep training failed. When the disruption passes, go back to your method from the start. The retraining period is almost always shorter than the initial round, often just a night or two, because your baby already has the underlying skill.
If your baby uses a pacifier and keeps throwing it out of the crib and crying for you to replace it, it’s fine to replace it once. If it becomes a game, stop replacing it. The pacifier is a tool your baby can learn to use independently, and at 4 months some babies haven’t figured out how to find and replace it themselves yet. You may need to decide whether the pacifier is helping or creating a new dependency.
Consistency is the single biggest predictor of success. Switching methods mid-course, giving in after 30 minutes of crying, or having one parent follow through while the other doesn’t will extend the process and increase the total amount of crying your baby does. Pick an approach both caregivers can commit to for at least a full week before evaluating whether it’s working.