Three weeks ago, she was sleeping five-hour stretches.
You’d told people. You’d texted your mum. You’d started to feel like maybe, finally, you had cracked something.
Then it stopped. Almost overnight. She started waking every 90 minutes again. Refused the first nap. Took 45 minutes to go down for the second one. The stretches you’d built shrank back to what they were at six weeks.
You went back and tried everything you’d tried before. None of it worked the same way.
Here is what’s actually going on. And it isn’t regression. Not in the way you’re thinking.
What a sleep regression actually is
The word “regression” makes it sound like something broke. Like your baby went backward. Like progress was lost.
It didn’t break. And the progress isn’t gone.
Sleep regressions are, almost without exception, the neurological side effect of a brain doing something impressive. At four months, a baby’s sleep architecture permanently changes, shifting from the simple two-stage sleep of a newborn to the multi-stage cycle that adults use for the rest of their lives. That’s a fundamental restructuring of how the brain processes sleep, happening in a matter of weeks.
At eight months, crawling, pulling to stand, and the beginning of language comprehension are all arriving simultaneously. The brain is so occupied with encoding new motor and cognitive skills that it literally cannot settle the way it did three weeks ago.
Your baby isn’t waking more because something went wrong. She’s waking more because her brain is working.
Regressions don’t last because the skill consolidates. Once the brain finishes encoding crawling, or the new sleep architecture stabilizes, the disruption resolves. Most regressions peak between one and three weeks. After that, sleep usually returns to baseline or improves on it.
What you actually need to do right now
Not much. Genuinely.
The instinct during a regression is to try new things. A different routine. A new technique. An earlier bedtime, a later one, a change to the nap structure.
Most of the time, those changes don’t help. They just add variables to an already chaotic week. And when the regression ends naturally, it becomes harder to know what worked.
The one thing that helps most, according to pediatric sleep research, is holding whatever routine you had before. Consistent bedtime sequence. Consistent response to waking. Not because it fixes the regression, but because it gives the baby something stable to return to when the developmental surge finishes.
If you want to understand exactly where your baby is in their developmental and sleep cycle right now, the age-specific guide on the blog is the most useful place to start. Parents of babies in this window find that the 9-month sleep schedule guide covers most of the questions that come up during this period.
The American Academy of Pediatrics publishes accessible research on infant sleep architecture and developmental regressions for parents who want the clinical picture.
The sleep you built isn’t gone.
It’s just paused while her brain does something remarkable.
Give it two weeks. Hold the routine. It comes back.