4-Month-Old Baby Sleep: 7 Things Parents Can Expect

Sleep regression is very real, and about as unpleasant as it sounds.

by Jayme Moye
Originally Published: 
4-month-old baby sleep

In case you needed the reminder, sleep is not a luxury, it is a biological necessity. And while you may have made it this far in your adult life by routinely sacrificing sleep for more interesting endeavors, it doesn’t work that way for babies. Critical development is underway while baby is asleep, from tissue repair to the formation of new brain synapses. That doesn’t mean it’s always easy to get your baby to fall asleep, or to stay asleep, even when baby needs it most. Hannah Peterson, a pediatric nurse and the owner and operator of Dream Baby Sleep Consulting, breaks down what kind of sleep to expect from your baby at four (to six) months.

You’re in the Home Stretch

Four months old is the age every parent is waiting for — when baby reaches 14.5 lbs, the weight doctors recommend for a baby to be able to go 8 hours in between feedings. But don’t get your hopes up too high. For many babies, it’s still too soon to expect them to sleep through the night. The magic moment is further down the road, around 6 months when baby starts eating solid foods, and the proteins help further stabilize her blood sugar.

Hormonal Changes Can Disrupt Nighttime Sleep

Similar to the shift at 2 months, your baby’s sleep hormones, the ones that control their sleep and wake cycles, are going through another major development, and this one can disrupt his nighttime sleep habits. At about four months, it’s typical for babies who were soundly sleeping 6-8 hours to suddenly start waking up every 1-2 hours. Parents often assume baby is hungry and feed him. He’s not, and feeding them can inadvertently set up a bad habit of “snacking” during the night. (See below).

The Time is Right for Sleep Training

At 4 months, your baby’s nervous system has developed enough that she’s capable of self-soothing, i.e. re-settling herself to fall back asleep. This is the age bracket when sleep training — the process of helping baby learn to fall asleep and stay asleep — begins. Brace yourself, because there’s a seemingly infinite amount of information on the topic, across the entire spectrum from “cry it out” to “no cry.” Peterson says not to stress too much about which is best, but rather to choose one that feels like the most natural fit for you and your family, and to strive for consistency.

Teething Comes into Play

Most babies get their first teeth at 4-6 months, and the 24-72 hours just before a new tooth comes through the gum can be uncomfortable enough to disrupt baby’s sleep. This is when sleep training really comes in handy, helping baby learn to go back to sleep after he’s woken by achy gums. And your doctor can advise you on remedies for teething discomfort that are appropriate to use at night.

Let Baby Roll Over

Around 4 months, babies begin to be able to roll on their own. Peterson says it’s fine to let baby sleep in a position other than on her back at this age, so long as baby is the one who moved herself there in the first place. Still, for safety reasons, mom and dad should continue to put baby down starting on her back, up until age 1.

The Time is Not Right for Stuffed Animals

At 4-6 months, the crib should still be free of blankets, objects, and bumpers. It isn’t until about 6 months when you can safely introduce a blanky or other soft, breathable object that baby can use to self-soothe.

Naps Don’t Change

The sweet spot for naps at 4-6 months is still three per day. While every baby is different, Peterson suggests organizing naps at this age as follows: a short-to-medium length nap (30-45 minutes) in the morning, a long, luxurious nap of 1.5-2 hours after lunch, and then a short power nap at the end of the afternoon to get them through dinnertime until it’s time to go down for the night.

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