A child who had been sleeping through the night starts crying awake around 18 months and thrashes against being put down. Parents often wonder what went wrong. This pattern is commonly called a “sleep regression,” and it is usually described as a temporary disruption tied to developmental changes rather than evidence that sleep habits have been spoiled.
Why It Happens
The Sleep Foundation notes that sleep problems tend to be more common around 9 months and 18 months. At these ages, sleep can be thrown off by a child’s growing ability to move around, greater awareness of surroundings, and feelings of separation anxiety. Language is also growing, and many toddlers start testing “no” and “I won’t.” On top of that, between about 18 and 24 months many children move from two naps to one, and that change can ripple into nighttime sleep.
How It Looks at Different Points
Common signs are fussiness, night waking, and shifting nap patterns. A child still taking two naps may nap too long in the afternoon and feel sleepy late at night. A child in the middle of dropping to one nap may be tired and cranky in the daytime for a few weeks. Settling into a single nap often takes anywhere from two weeks to a month. In most cases an 18-month regression is short-lived, and it tends to pass sooner when caregivers keep healthy sleep habits in place.
Managing It at Home
First, add up total sleep. The AASM consensus statement, endorsed by the American Academy of Pediatrics, recommends 11-14 hours per 24 hours (naps included) for ages 1-2. Second, keep a bedtime routine of about 20-30 minutes in the same order: bath, pajamas, a book, lights out. Third, when your child wakes and cries, respond in the calm, brief way described by National Jewish Health: short reassurance, no lights or play, and a return to bed while still drowsy, repeated consistently. Fourth, end the afternoon nap early enough that bedtime isn’t pushed late, and keep the hour before bed free of rough play and screens. Changing methods every night can leave a toddler more confused, so sticking with one approach for 1-2 weeks is usually more useful.
Common Misunderstandings
Many parents worry that holding a child to sleep will create a bad habit. During a spell of heightened anxiety, extra comfort may actually help a child settle. The catch is that adding a new sleep prop each night, such as car rides or restarting night feeds, can leave that prop needed after the regression ends. The opposite mistake is assuming the phase will simply pass and letting bedtime and routine drift, which may stretch the regression out.
When to Consider Talking with a Pediatrician
Consider a pediatric visit if night waking lasts more than a month or two, if loud snoring or pauses in breathing appear, if fever or ear-pulling suggests pain, or if extreme daytime sleepiness or unusual listlessness continues. This information isn’t a diagnostic tool and doesn’t replace advice from a medical professional.