4 month sleep regression

Around 3 to 4 months, many babies who were sleeping longer stretches start to wake more often. Here is what is known about why, how long it tends to last and what you can do tonight.

What is the 4 month sleep regression?

Sleep regression is a popular name for a stretch of worse sleep in a baby who was sleeping better before. It is not an event that research has pinned to the calendar: Cleveland Clinic notes that research has not shown regressions happening like clockwork at a specific age for every baby.

Four months is the age parents talk about most, and it is not uncommon for sleep to get worse around then. Not all babies go through it.

Why sleep changes around 4 months

At around 3 to 4 months a baby's sleep starts to include lighter stages, more like an adult's. Adjusting to those lighter phases can make babies more likely to wake up (Cleveland Clinic).

A baby who wakes between sleep cycles and has always been fed or rocked to sleep often wants the same help to get back to sleep. That is why wakings can multiply at this age even though nothing is wrong.

How long does the 4 month sleep regression last?

Cleveland Clinic says regressions typically last a week or two. The Sleep Foundation says that in most cases the trouble lasts a few days to a few weeks. Nobody can give you a date, and it is different for every child.

What to do

• Rule out other causes first. Illness, hunger and a wet diaper can look the same.
• Feed your baby when they wake hungry. Many 4 month olds still need a feed at night.
• Keep the same short bedtime routine every night, in the same order.
• Lay your baby down drowsy but awake when you can, so they practice falling asleep in the crib.
• Keep night feeds dark and quiet: lights low, a soft voice, no play.
• Watch awake times. About 1.25 to 2.5 hours at a stretch is the rule of thumb at this age.
• Stop swaddling as soon as your baby shows any sign of trying to roll over, which often comes at 3 to 4 months.

Can you sleep train during the 4 month sleep regression?

It depends who you ask, and no medical body sets an age. Cleveland Clinic says babies are often ready at about 4 months. Dr. Richard Ferber's book says five or six months, and the published trials enrolled babies of 6 months and older.

Our plans use a method where you stay in the room at this age, and add timed checks and the say-goodnight method from 6 months. If you are unsure, start with the schedule and the bedtime routine and ask your pediatrician about the rest.

When to call the pediatrician

Talk to your pediatrician if sleep does not get back on track, if something does not seem right to you, or if you notice snoring, trouble breathing, a fever, poor weight gain or feeds that are a struggle.

Related guides

• 4 month old sleep schedule
• Sleep regression ages
• When to start sleep training

Sources

• Cleveland Clinic. The 4-Month Sleep Regression: What Parents Need To Know. July 2022.
• Sleep Foundation. 4-Month Sleep Regression. Updated July 2025.
• Cleveland Clinic. When and How To Sleep Train Your Baby. January 2025.
• Moon RY, et al. Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment. Pediatrics, 2022.

General information for parents, not medical advice. Independent, not affiliated with the American Academy of Pediatrics or any medical body. Talk to your pediatrician about your baby's health.