Bedtime went perfectly. They went down without a fight, you crept out, you sat down — and forty-five minutes later they're awake and it's like the whole night has restarted.

That's what we call a false start. And the reason it's so confusing is that you're looking for the problem in the wrong place. It almost never happens because of something you did at bedtime. It happens because of something in the day.

What a false start actually is

A false start is when your baby wakes up somewhere in the 30 to 45 minute range after you've put them down for the night — roughly one sleep cycle, sometimes a bit less, sometimes up to an hour. Instead of moving into the next cycle, they fully wake up, and you're back in the room resettling a baby you only just settled.

It's worth being clear about what it isn't. If your baby sleeps more than an hour and then wakes, that's not a false start — that's a baby who connected a sleep cycle on their own and woke later. And waking every couple of hours through the night is a different thing again, with different causes.

So if you're reading this at 8pm with a baby who's just popped up after forty minutes, you're in the right place.

My rule: if bedtime goes wrong, look at the day

This is the first thing I say to every family, and it's the thing that changes how you think about the whole problem.

Everything that happens during your baby's day — their naps, their awake times, when they ate — directly affects how bedtime is going to go. By the time you're standing at the crib at 7:45pm, the night has largely already been decided. The bit you can actually change happened hours earlier.

Which is good news, honestly. It means there's something to adjust rather than something to endure.

The two most common causes are opposites

Most false starts come down to sleep pressure — how much of a drive to sleep your baby has built up by the time you put them down. And it can go wrong in both directions.

Not enough sleep pressure. Your baby hasn't been awake long enough across the day, and often that shows up as lots of short naps. By bedtime they're just not tired enough yet, so after that first sleep cycle they wake up — because as far as their body is concerned, they've had a nap.

Too much. If your baby has been awake too long, or hasn't got enough daytime sleep, they arrive at bedtime overtired. Cortisol, which is a stress hormone, spikes when a baby gets overtired, and that makes it harder for them both to fall asleep and to stay asleep through the natural transitions between cycles.

There's a third thing that sits alongside these: the last nap. If it finishes too late, or runs too long, it eats into the sleep pressure you need for bedtime — and you'll see the same result.

Here's the part nobody tells you

You cannot work out which one you're dealing with by watching bedtime.

I know the internet will tell you that a baby who falls asleep in five minutes is overtired and a baby who takes ages is undertired. It isn't that clean. An overtired baby can absolutely crash and be asleep in minutes — and then be awake forty-five minutes later. But an overtired baby can also really struggle to fall asleep at all, because of that cortisol spike.

I know that sounds contradictory, but both can be true.

So the tell isn't at bedtime. It's in the day. Look at how much total sleep they've had in twenty-four hours, how many naps, how long they were awake before bed, what time the day started, and what time that last nap ended. That's where the answer is.

What to actually change

Start with one thing and move it in small increments — five, ten, or twenty minutes. Not an hour. Small changes make a bigger difference than people expect, and big ones make it impossible to tell what worked.

If it looks like there isn't enough sleep pressure, the usual move is to lengthen the awake time before bed — often by shortening or capping that last nap, and it's completely fine to wake a baby up to do it.

If it looks like overtiredness, bring bedtime forward a little instead.

Then give it a few nights before you judge it. One night tells you nothing.

If you're not sure where to start with awake times, I've got a free awake times chart that gives you a guide for how long your little one should be awake at each age, from birth to three years. It's a starting point rather than a rule - every baby is different. Wake windows are also not evidence-based so there is no exact wake window to follow. Take this as a guide as well as watching out for your little one's sleepy cues. You can download it from the free sleep resources section of my website.

The other things worth checking

The day started too late. If they woke late and everything shifted, they simply haven't been awake long enough by bedtime.

The sleep environment. Dark, cool, and white noise if there's noise in the house that might wake them. Get down at your baby's level and feel what it's actually like in there — the temperature and the draft at crib height can be quite different from the middle of the room.

Separation anxiety. This is a real one and it doesn't get talked about enough. Somewhere around six to eight months, a lot of babies develop object permanence — they work out that things still exist even when they can't see them. It's a big developmental leap, and it also means that when you walk out of the room, your baby now understands you've gone somewhere rather than simply stopped existing. That can make being put down on their own much harder than it was a month earlier. If your baby wakes after that first cycle and settles almost as soon as you come in, this is often what's going on.

The one a schedule change won't fix

Here's the thing I'd want you to know before you spend three weeks moving bedtime around.

If your baby falls asleep at bedtime with help — fed to sleep, rocked to sleep, held until they go — then for many babies, that's the same thing they need to start a new sleep cycle. So when they come to the end of that first one and it's gone, they wake up properly instead of settling back down.

Not every baby, though. Some are rocked or fed to sleep and still only wake once or twice, and if that's working for your family then there's nothing here you need to change. But if you're up over and over and moving the schedule around hasn't touched it, this is usually why — because the schedule was never the problem.

It's the same thing behind waking repeatedly through the night.

So how long do false starts last?

As long as the cause does.

This isn't a phase you wait out. I'm not going to tell you they'll grow out of it around a year, because that's a year of your evenings. It lasts until the right change gets made — and most of the work is figuring out which change that is.

Once you find out the root cause, things usually move quite quickly.

Where to go from here

If the schedule side is what you need, and you've got a baby between five and eighteen months, my 5-18 Months Sleep Program walks you through the whole day structure — how much daytime sleep they need at their age, how to time that last nap, and how to gently build falling asleep independently so the first sleep cycle isn't a cliff edge every night. It's 100 minutes of short videos, and it keeps working as they grow, which matters because the right structure at six months isn't the right structure at eleven.

If your baby is younger, the 3-4 Month Sleep Program is the one for you.

Common questions

Is a false start the same as waking every two hours?

No. A false start is that first wake, 30 to 45 minutes after bedtime. Waking every couple of hours through the night is a separate pattern with different causes.

Should I treat the false start like a night waking or like a nap?

Treat it as a night waking. Keep it dark and boring, and resettle the way you would at 2am.

My baby only wakes once and then sleeps for hours. Is that a false start?

It is, and it's one of the most common patterns there is — a false start early on and then a long stretch afterwards.

Could it be teething?

Almost certainly not for weeks on end. Teething symptoms only line up with a tooth on the day it comes through and the day after — more on that here.

Do I need to change bedtime or the naps first?

Change one thing at a time, and start with whichever looks furthest off. If you change both, you won't know which one did it.