4-month sleep regression

What It Means

The 4-month sleep regressionSleep regressionA stretch when a baby or toddler who was sleeping fairly well starts waking more at night or fighting sleep, usually for a week or two. See more is what parents call a stretch of more frequent night waking and fussiness that often shows up around 4 months. Cleveland Clinic says this is the age most talked about for a regression and that it typically passes in a week or two. It's also the age when, according to Cleveland Clinic, a baby's sleep cycles begin to mature and their body clockCircadian rhythmThe body's roughly 24-hour cycle of physical, mental and behavioral changes, such as sleepiness at night, kept in time by a clock in the brain that follows light. See more starts to take effect, so sleep is changing shape. The name is everyday language; the AAP and the American Academy of Sleep Medicine don't use it.

How Parents Say It

• "She hit the 4-month regression right on time."
• "He was sleeping six hours and now it's every two."
• "Everyone warned me about four months."

The Breakdown

Around 4 months, from the sources

What helps

1. Keep a calm, predictable routine before naps and bedtime.
2. Lay your baby down drowsy but awakeDrowsy but awakeLaying a baby down in the crib when they're sleepy but still awake, so they practice falling asleep on their own. See more, as HealthyChildren.org suggests.
3. Give a few minutes before going in when your baby stirs at night.
4. If you've decided to sleep train, Cleveland Clinic notes that around 4 months is when many babies are ready.

When to talk to the doctor. Call your pediatrician if the worse sleep lasts well beyond a week or two, if your baby is feeding poorly or seems ill, or if something doesn't seem right.

Good to Know

Research hasn't shown regressions arriving like clockwork at one age for every baby, Cleveland Clinic says, so yours may come earlier, later or not at all. HealthyChildren.org adds that solid food before about 6 months won't help a baby sleep through the night. Keep every sleep safe: on the back, in the baby's own sleep space, on a firm, flat surface with only a fitted sheet.

Related Terms and Categories

• Sleep regression

  A stretch when a baby or toddler who was sleeping fairly well starts waking more at night or fighting sleep, usually for a week or two.

• Wake window

  The stretch of time a baby stays awake between one sleep and the next, often used as a rough guide to when the next nap is due.

• Nap schedule

  The usual pattern of a baby's or toddler's daytime naps: how many, roughly when and for how long, which shifts as the child grows.

• Drowsy but awake

  Laying a baby down in the crib when they're sleepy but still awake, so they practice falling asleep on their own.

• Sleep training

  Teaching a baby to fall asleep on their own, both at bedtime and after waking in the night, using a planned, consistent method.

Baby and toddler