Between 14 and 18 months, many babies who were sleeping well suddenly are no longer sleeping. Naps are denied, bedtime becomes a game of wrestling, and 5 a.m. wake-ups appear sudden. Parents often believe that regression has set in, and they may be right. But this age also sits on top of one of the biggest schedule changes of childhood the move from two naps to one. Knowing what you’re dealing with changes how you fix it.
What is happening developmentally at 15 months?
This is a busy stage of brain development. Most children are walking or about to walk, and the desire to exercise is strong. Language is exploding, with new words emerging weekly. Separation anxiety often returns with force as children become more aware of your leaving. Around this time, molars also often start falling.
Any of these can disrupt sleep. All of these things combined, which are common, can make a baby who sleeps easily at first seem like a completely different baby. The good news is that this type of developmental disruption is temporary and usually resolves within two to four weeks.
What does nap infection look like
Most babies go from two naps to one between 14 and 18 months. This rarely happens with cleanliness. For a few weeks, two naps seem like too much sleep and one nap doesn’t seem like enough. The result looks a lot like regression: refusal to take a nap, sleeping late, waking up at night due to extreme fatigue, and waking up early in the morning.
How to tell the two apart
Specifically look at what’s happening with naps. In pure developmental regression, naps often last about the same duration but take longer to stabilize, and the main interruption occurs at night. In nap transition, the nap itself is a problem. Someone is being abandoned, rejected, or shrunk, and the nighttime disruption stems from that.
Specifically look at what’s happening with naps. In pure developmental regression, naps often last about the same duration but take longer to stabilize, and the main interruption occurs at night. In nap transition, the nap itself is a problem. Someone is being abandoned, rejected, or shrunk, and the nighttime disruption stems from that.
Why are they often together
The 15 month sleep regression for babies for infants the 15-month sleep regression and the transition from two to one naps overlap so closely in age that many babies experience both at the same time. Developmental leaps reduce their desire to settle, and changing sleep needs shorten the window in which it is easier to settle. Each makes the other difficult.
When both are at play, prioritize the safety of your night’s sleep. The timing of the day may be out of whack for a few weeks, but a consistent bedtime routine and regular morning wake-up time keep the body clock in order while everything else takes care of itself.
Managing Infections Without Ruining Nights
If your baby is showing signs of being ready for a nap, you don’t need to skip the second nap overnight. Slowly works better for most families and reduces excessive fatigue caused by waking up at night.
Bridging approach
Every few days, extend your morning nap by 15 to 30 minutes. As it moves towards the afternoon, it naturally becomes the only nap. On days when your child is unable to stay up late, give him a short nap in the morning and a proper nap in the afternoon. Adopt an earlier bedtime on any day when total daytime sleep is less.
When to take two naps
If your child is under 14 months old, still taking two solid naps most days, and this disruption occurs primarily at night, resist the urge to skip naps. The regression is likely developmental, and removing sleep will make it worse. Maintain a schedule, provide extra reassurance, and wait.
Dealing with separation anxiety at bedtime
If stiffness and tears at goodnight are part of your picture, keep the bedtime routine consistent and predictable. Spend the last ten minutes being completely present, without calls and without any rush. Say a short, confident goodbye and walk away. Repeatedly returning or lingering at the door increases anxiety rather than reducing it, as it signals that going out is uncertain.
During the day, practice brief separations in low-risk situations. Leave the room for a minute while they play, then come back happily. This creates a sense that you always return, making it easier to say goodbye to bedtime over time.
Closing Thoughts
The 15 to 18 month period is the collision point between actual developmental regression and one of the biggest schedule changes of childhood. Look at the nap first. If they are being rejected or minimized, transition is at least part of the story, and a gradual change in a nap will help. If naps are OK but nights are difficult, maintain your schedule and support developmental leaps with consistency and connection.
