Wake Windows at 4 Months: Timing Naps Through the Regression

Four months is the age of the best-known sleep regression. Around this point, your baby's sleep changes in nature: it leaves newborn sleep behind and adopts structured cycles, closer to an adult's, with phases of light sleep between each one. At the end of a cycle your baby surfaces, and if they can't yet fall back asleep alone, they call for you. This regression typically lasts 2 to 6 weeks, and it is the only one that reflects a lasting change. Good daytime timing helps: an overtired baby sleeps worse.

A sample day at 4 months

Example only. At 4 months, many babies handle the upper part of the 75 minutes to 2 hours range, but during the regression a shorter window can work better.

• 7:00 am: wake-up.
• Around 8:30-9:00 am: first nap, 1.5-2 hours after waking.
• If that nap lasts an hour, your baby is up around 9:45 am, so the next nap falls around 11:15-11:45 am.
• One or two more naps in the afternoon, for 3 to 4 in all.
• Bedtime comes after the last window of the day, often the longest.

If naps get short during the regression, simply restart the count from each wake-up rather than following the clock.

Signs to watch at 4 months

• Overtired cues: crying, back arching, a burst of hyperactivity. During the regression, aim to put your baby down at the very first cues (staring, yawning, rubbing eyes).
• Night wakings between cycles: wait a minute or two before stepping in; babies often fuss between cycles without being truly awake.
• New habits: rocking or feeding at every waking helps in the moment but builds a habit you'll later have to undo.

A regression that drags past 6 weeks, worsens, or comes with fever, unusual crying or loss of appetite needs a pediatrician's opinion. Ambrette shows sleep trends across several days, so you can see when the regression starts to ease.

Frequently asked questions

Does the 4-month regression change wake windows?

Not the window itself, but it makes respecting it more important, because an overtired baby sleeps worse. Keep the same routine and timing, and expect this regression to last about 2 to 6 weeks.

How many naps at 4 months?

Usually 3 to 4 naps a day, with about 4-5 hours of daytime sleep and 13-16 hours of sleep in total over 24 hours, naps included.

Why does my 4-month-old suddenly wake after every sleep cycle?

Around 4 months, sleep matures into structured cycles with light sleep between each one. A baby who can't yet link cycles alone wakes and calls for you. Wakings space out as they learn to resettle.