It can be a frustrating, confusing, and exhausting time.

Your baby was sleeping well, and you thought things were only going to get better. There were long stretches at night, then suddenly, your baby started waking every two to three hours again, or every hour, or every 45 minutes.

Often this begins just after 3 months of age and can last a few weeks before we finally realize that they have regressed.

The four-month sleep regression is in fact, not a regression at all. I’ll explain why. An actual regression in sleep is the result of development milestones (rolling both directions, crawling, walking), or a setback due to sickness or travel. When sleep regressions of these types appear, we see babies who go from sleeping through the night turn into babies who wake and cry out in the night or have difficulty going to sleep. With consistent adherence to the baby’s regular sleep routine, the baby’s healthy sleep habits should soon reappear, often within a week or two.

What is happening around four months is different from an actual regression. Your child’s sleep is becoming less like that of a newborn and more like that of a child, with actual sleep cycles of around 40 minutes.

We all wake at night, often, but for us we can get back to sleep so quickly by rolling over that we don’t fully wake up. For babies who can’t go back to sleep on their own after they wake from a sleep cycle, they may cry out for whatever method was used to help them go to sleep in the first place.

Newborn babies can often fall asleep pretty quickly and easily. You could either hold your baby, wear your baby, nurse your baby, rock your baby, bottle feed your baby, and most likely, your baby fell asleep easily. Somewhere around the third to fourth month of your baby’s life, your baby’s brain begins to mature. They are more aware of their surroundings, and they spend less time in REM sleep and a lot more time in light-stage sleep, which can make it more difficult for them to fall asleep assisted.

A four-month-old, like an adult, moves more slowly through the stages of sleep, from being sleepy to light sleep, then to deep sleep. While you can rock your two-month-old to sleep in 15 minutes, and put him down, if you try rocking your four-month-old to sleep he will likely startle awake as soon as you put him down. This is because he was still in the light stages of sleep when you tried to put him down. If you want to continue to rock your baby to sleep, it can take a very long time before he finally falls into a deep sleep allowing you to put him down without startling him awake.

Around four months of age, your baby also spends more time in non-REM deep sleep. This means that when he finishes a sleep cycle in the night (thereby experiencing a partial awakening), it can be troubling if he doesn’t know how to get himself back to sleep, and transition to the next sleep cycle. Those normal partial arousals we all experience (even adults wake up to 4 times a night) are now very obvious to him. If he hasn’t had practice getting from drowsy to asleep on his own, it becomes a big problem. It isn’t that your baby is waking more often, it’s that he doesn’t have the skills to get back to sleep on his own and is looking for whatever helped him fall asleep at bedtime (nursing to sleep, rocking to sleep, bottle feeding to sleep, etc). These are referred to as his “sleep props”. Nursing or bottle-feeding by itself is a problem, but when it is a vehicle to get a baby to go to sleep, these problems can be known to happen.

On a lighter note, the four-month regression doesn’t affect every baby! There are babies whose parents have worked from the beginning to establish healthy sleep habits, and these babies tend to sail right through this time unaffected, or with very little disruption to their sleep. If you are finding that you are struggling through this time right now, or that you never found your way out of it, book a call so that we can talk about your own child’s individual sleep issues.