Newborn sleep doesn't follow adult logic. Here's how it actually works, and why your baby is waking every 90 minutes.
If you have a newborn, the first thing nobody warns you about is how their sleep is structured. It's not "shorter than adult sleep." It's fundamentally different. Knowing the shape of it makes the chaos feel less like failure.
Newborns sleep ~16 hours a day — in 1 to 4 hour chunks
Total sleep in 24 hours:
- Newborn (0–4 weeks): 14–17 hours
- 6–12 weeks: 14–16 hours
- 3–6 months: 12–15 hours
That's a lot of sleep. The catch: it's spread across 4–8 separate chunks, day and night, with no preference for one over the other.
Your newborn doesn't know night from day yet. Their internal clock (circadian rhythm) takes about 6–8 weeks to develop. Until then, they sleep when they sleep.
Why they wake so often
Adult sleep cycles are about 90 minutes long. Newborn cycles are roughly 40–50 minutes, and they spend about half of each cycle in active sleep (REM-like), where they're easily roused.
Active sleep looks like:
- Twitchy limbs and facial movements
- Eyes moving under closed lids
- Sometimes light fussing or grunting
If you pick them up the moment they stir, you might be interrupting active sleep — which is normal and self-resolving in most cases. Try waiting 2–3 minutes first.
The 4-month change
Around 3–5 months, sleep cycles mature toward something closer to adult structure. This is the so-called "4-month sleep regression" — a misnomer, since it's actually progress. Your baby's sleep is becoming more organised, but the transition can feel like a step backward.
What's normal at every stage
| Age | Total sleep | Longest stretch |
|---|---|---|
| 0–4 weeks | 14–17h | 2–4h |
| 1–3 months | 14–16h | 4–6h |
| 3–6 months | 12–15h | 6–8h |
| 6–12 months | 11–14h | 8–10h |
These are averages. Your baby may sleep more or less and still be healthy.
Survival, not strategy
The first 8 weeks aren't about training. They're about getting through. If sleep training is on your radar, most evidence-based approaches start at 4 months at the earliest — and many parents do nothing formal at all and end up with great sleepers.
Always follow safe sleep guidelines: on the back, in their own crib or bassinet, on a firm flat surface, no loose bedding, no bumpers, no positioners. SIDS risk is real and these basics matter.
Track patterns, not perfection
Sleep tracking gets obsessive fast. The point isn't a perfect chart — it's spotting genuine shifts: a 4-week-old who suddenly cuts sleep in half, or a 5-month-old who can't be put down.
The takeaway
Your newborn's sleep is broken-up, half-light, and indifferent to your schedule — and all of that is normal. It will get more organised on its own, mostly between months 3 and 5. Until then, the goal is rest where you can get it, not "fixing" anything.