Though it doesn’t show up in many medical resources, “sleep regression” is a fairly common term when it comes to conversations about baby sleep. In some ways, it’s not always a useful way to talk about the fact that, just like adults, sometimes a baby’s sleep is affected by the things going on in her life. Since one of the biggest events in a baby’s life is her own growth, and a lot of the time, babies’ growth follows a fairly predictable pattern, it’s sometimes possible to predict approximately when these regressions might happen.
A sleep regression is the term many sleep consultants use to describe what happens when a baby who has previously slept through the night, or fallen into a regular napping pattern, starts resisting sleep or waking up in the middle of the night. This can go on for several days or even weeks.
Babies and toddlers can regress, or seem to lose skills that they’ve already mastered, in a few different areas, most commonly in feeding, potty training, or sleep. It’s usually a normal part of development that passes on its own, but some regressions, like regression in language skills, or regressions that don’t pass on their own, can be signs of possible problems, and should be brought up with a child’s pediatrician.
One of the main theories about regression is that regression, whether it’s a sleep regression, a regression in feeding skills, or, later on, a potty training regression, often happens when a baby or toddler is hard at work learning a new skill, and so a regression might come before, say, a leap forward in language development, a first step, or another big milestone. The other common potential reason for regression is stress - learning new skills generally gives babies and toddlers new and interesting ways to explore their independence. But when a baby or toddler is stressed, she might revert to old patterns or habits that require you or other parents or caregivers to do more to take care of her, whether that means spoon-feeding or coming into the room in the middle of the night to soothe her to sleep. Being ‘babied’ a little is soothing to babies, and doesn’t mean that they’ve lost the skills they had before. They’re just going through a hard time, and looking for a little extra help.
There hasn’t been official or scientific study of the connection, but just from anecdotal and observational evidence, sleep regressions often seem to line up with, or come just before, some growth spurts. One sleep-advice site suggests that sleep regressions tend to happen once every 4 months or so in the first year, which is a timeline that lines up fairly well with some of the big growth spurts in that year. Growth spurts have also been associated with increased sleep in babies and toddlers, though, so there’s no guarantee what effect growth spurts will have on sleep, if any.
Stirring during the night isn’t necessarily regression, and waking up briefly during the night doesn’t mean that a baby can’t still sleep through the night. Just like adults, babies occasionally wake up between sleep cycles, and a lot of the time, they can fall back asleep fairly easily on their own. Unlike adults, though, babies have concerned parents keeping an eye on their sleep, which means that these brief wakings don’t have as good of a chance of being brief blips that are forgotten by morning than adults’ slightly restless sleep. Pausing a moment when you hear your baby during the night to see if she drops right back into sleep of her own is a good policy for working towards uninterrupted nights’ sleep.