Why does my baby sleep through every noise?

A doctor told us it changes after the first month

She slept through everything — conversation, television, doors, the lot. And we were told it wouldn't last past the first month or so. It was lovely.

That's broadly right, and the reason is development rather than anything you do.

Why it changes

Newborn sleep is deep and less organised, so a young baby can ignore a surprising amount of noise. As she grows, she spends more time in lighter sleep and notices more around her.

So a baby who becomes noise-sensitive at two months hasn't been spoiled by quiet, and one who stays unbothered hasn't been toughened up. Both are ordinary.

It also means the window where you can hoover next to a sleeping baby is finite, and worth enjoying.

What we'd do from the start

Carry on normally. Don't build a silent house you'll then have to maintain, because you won't be able to.

Use consistent background noise rather than silence. White noise, a fan, or just the ordinary sound of a household. It masks the sudden noises — a door, a dog, a delivery — which are what actually wake babies, rather than steady sound.

If you use a machine, one that runs continuously rather than stopping after fifteen minutes. A track that cuts out mid-nap is worse than no track at all. Papa was putting Ari to bed, she was about to sleep, he had everything ready, it had taken him 30 minutes to put her to sleep this time, and the moment she was just about to nod off the white nosie machine stopped. Ari woke up. Papa had forgotten to change the setting to continuous and he had to start all over again.

And keep it at a sensible volume, across the room rather than beside her head.

A baby who sleeps through everything is almost always just a good sleeper.

But if she never startles at a sudden loud sound, or doesn't turn towards your voice as she gets older, that's worth mentioning — particularly if she was premature or spent time in neonatal care and you're not certain her hearing has been formally checked.

It's a two-minute question and it's better asked than assumed.