Sleep regressions are real — but calling them regressions misses what's actually happening. Your baby is progressing, not going backwards.
If you search "sleep regression" you'll find hundreds of articles telling you exactly when they happen. If you search the medical literature, you'll find almost nothing. Here's why that gap matters.
You had it figured out. Not perfectly, but you were getting stretches. And then it stopped. This is for the parent in the middle of it — not more information, just the things that are true and worth hearing right now.
If your 3–5 month old has suddenly gone from sleeping in decent stretches to waking every 1–2 hours, you're experiencing the most well-documented sleep change of infancy. Here's what's happening — and why nothing has gone wrong.
The 4-month sleep change is real, but calling it a regression frames it as a step backwards. It's actually a step forwards — just one that's hard to live through.