This is a quick read, so you can get back to your regularly scheduled not-sleeping, stat. 

Sleep regression is a term only loosely understood by parents, until they actually experience it. And then the full picture of what sleep regression means — and how the ripple effects can spread to fussiness or bad behaviour from being overtired — becomes fully clear, even as your eyes grow bleary from fatigue.

What and when are the signs of sleep regression?

Sleep regression colloquially refers to a moment in a baby’s life when her sleeping patterns go completely for a toss. Many parents experience these regressions at 4 months, 9 months, and 18 months (give or take a few weeks), but the truth is that they can happen any time. These moments are usually defined by the baby’s complete rejection of her earlier sleeping habits and schedule. She may start to buck bedtimes, or shriek at the start of a bedtime routine. Or she may start waking up at times during the night that she never did before. Crying, asking to be held, or simply turning an established bedtime routine upside-down are also signs of sleep regression.

What this means for parents? When you least expect it, so-called sleep regression can make a parent’s life very, very unpleasant.

What causes sleep regression?

Most frequently, parents hear about the “four-month sleep regression,” but the truth is that the symptoms of sleep regression can occur any time the baby or toddler is experiencing a major developmental leap. (The main reason so many parents experience this issue around the four-month mark is simply that this is a very busy time for baby’s brains, and they are usually crossing a lot of neuro-developmental milestones around this time.)

But early childhood is full of major, rapid-fire brain development, and every time a baby or toddler crosses a major milestone or makes a huge developmental leap, there may be some disrupted sleep. These developmental leaps could be physical, like when the baby is about to crawl, or is going through a growth spurt, or they could be cognitive or emotional, such as when the baby is processing speech and honing verbal skills.

So in those moments of sleepless frustration, it’s important to remember that sleep regressions are a good sign; your child’s brain is growing and changing and evolving, and disrupted sleep is simply one of the tangible indicators of this growth.

Can sleep regression be “cured”?

In short, no. As we’ve already pointed out, these are natural stumbling blocks on the way to developmental progress, so they cannot be avoided. That said, some babies will exhibit these sleep disruptions, and others will not. Those that do just need a little hand-holding to get through the rough patches.

The best thing you can do for your baby is maintain consistency around bedtime and sleep routines as much as possible. This will help you get back on track as soon as your baby is developmentally ready. Sleep regressions can last anywhere from a few days to a few weeks, which leads us to the most important point: Take heart, because this too shall pass. Sleep regression roadblocks are finite, and just when you think your baby has lost it and will never sleep through the night again, she might surprise you.