The Four Month Sleep Regression Explained

November 19, 2021

Registered Nurse Pam Jones has been helping new babies and parents since 2009. We collaborated with Pam on The Four Month Sleep Regression Explained, to help parents and nannies understand how to help baby sleep peacefully during and after this milestone.

In order to understand what’s happening to your baby during this stage, we first need talk about sleep in general:

The 4 Stages of the Sleep Cycle

Many of us just think of sleep as an on-or-off situation. You’re either asleep or you’re not. But sleep actually has a number of different stages, and they make up the “sleep cycle,” which we go through several times a night.

• Stage 1 is that initial stage we’re all familiar with where you can just feel yourself drifting off, but don’t really feel like you’ve fallen asleep. Anyone who has ever seen their partner nod off in front of the TV, told them to go to bed, and gotten the response of, “I wasn’t sleeping!” knows exactly what this looks like.

• Stage 2, considered the first “true sleep” stage. This is where people tend to realize, once woken up, that they actually were sleeping.

• Stage 3 is deep and regenerative. Also known as “slow wave” sleep, this is where the body starts repairing and rejuvenating the immune system, muscles tissue, energy stores, and sparks growth and development.

• Stage 4 is REM (rapid eye movement) sleep. This is where the brain starts to kick in and consolidates information and memories from the day before. It’s also the stage where we do most of our dreaming.

Once we’ve gone through all of the stages, we either wake up or come close to waking up, and then start over again until morning.

The Four Month Sleep Regression Explained

Newborn babies only have 2 stages of sleep; stage 3 and REM, and they spend about half their sleep in each stage. At around the third or fourth month, there’s a reorganization of sleep, as they embrace the 4-stage method of sleep described above. Here is the Four Month Sleep Regression Explained.

• REM and Waking Up – When the change to the 4 stage method of sleep takes place, baby moves from 50% REM sleep to 25% in order to make room for those first two stages. Although REM sleep is light, it’s not as light as the 2 new stages of sleep they’re getting used to. With more time spent in lighter sleep, there’s more of a chance that baby will wake up.

Waking up is absolutely natural, and we continue to wake up three, four, five times a night into adulthood. As adults however, we’re able to recognize that we’re in bed and safe and we go back to sleep. This usually happens so quickly that we don’t even remember these brief encounters with consciousness.

A four month old baby, of course, lacks these critical thinking skills, and to a baby who’s fallen asleep at the breast for example, waking up alone in a different location can be jarring! Baby most likely will not go back to sleep without a significant amount of reassurance that everything is OK.

What About Pacifiers?

• Pacifiers and Soothing – The other major contributor to this 4 month regression, is that up until this point, baby is used to going to to sleep with a pacifier, or by being rocked or breastfed. These are all perfectly appropriate for newborns. At 4 months however, baby may need new ways to get back to sleep after the initial nodding off because more time is spent in light sleep with higher probability of waking up. Pacifiers and the like are appropriate in the newborn stage and in helping baby initially nod-off, but the lack of a pacifier or being rocked when they wake up means that baby’s not able to get back to sleep again without this “outside help”. Cue the fight-or-flight, the crying, and the adrenaline…

The good news for anyone experiencing Four Month Sleep Regression is that it’s not, in fact, a regression at all. Regression is defined as “reversion to an earlier mental or behavioral level,” and that’s actually the opposite of what your baby is experiencing! This would be much more aptly titled the “Four Month Sleep Progression”

Pam Jones, RN

What you can do to help your little one through the Four Month Regression

• Baby’s room should be dark… – Newborns and infants are not afraid of the dark. They are, however, responsive to light. Light tells their brains that it’s time for activity and alertness, and the brain secretes hormones accordingly, so we want to keep that nursery absolutely pitch black during naps and bedtime.

• …And quiet – The other nemesis of sleep is noise. With more time spent in lighter sleep, noises can startle baby awake so white noise is a great addition to your nursery.

• Instill a Bedtime Routine – Bedtime routines should be about 20 – 30 minutes long, and baby should go into their crib while they’re still awake. Feeding should happen first with songs, story (or whatever calm activity baby likes!) and getting into PJs at the end. Feeding shouldn’t happen at the end of the bedtime routine because baby might nod off at the breast or bottle. This creates an association with feeding in order to sleep that parents can’t continue to do every time baby wakes up.

Four month old infants typically go about two hours between snoozes, with bedtime between 7 and 8 at night. Once babies graduate from the four month sleep progression, they follow the sleep patterns they’ll have for the rest of their lives…four glorious stages repeated multiple times a night!

Of course, some kids are going to take to this process like a fish to water, and some are going to be a little more resistant. If yours falls into the former category, count yourself lucky! For those of you in the latter camp, Pam Jones, RN is here to help. You can contact Pam at www.sweetdreamslittleones.com or 708-822-0059 for a personalized program for your little one.