Separation anxiety and sleep
They have just understood you exist even when they cannot see you. Excellent news for their brain, very bad news for their nights.
Eight months. Your baby has been sleeping through for three months, and overnight they wake three times, scream the moment you leave the room, and refuse to fall asleep without you.
You look for what you did wrong. You blame the teeth, nursery, a change of milk.
It is none of that. They have just understood something enormous.
What they have just understood
Until seven or eight months, for a baby, what leaves their field of vision roughly stops existing. That is why a toy hidden under a cloth stops interesting them, and why you could leave the room without drama.
Then comes what psychologists call object permanence: they understand that things — and people — carry on existing when they can no longer see them.
That is a considerable leap forward. It is also a disaster for their nights. Because now, when they wake at 2 a.m. and you are not there, they know you are somewhere. And that they can call you.
Every cycle end becomes a chance to check you are there
1 h au total, à partir de l'endormissement
- Sommeil léger
- Sommeil profond
- Sommeil paradoxal
Before, a micro-waking was just a micro-waking. Now it is a check.
What actually helps
Peekaboo. It sounds ridiculous, and it is the best tool you have. Disappearing and reappearing during the day, in a cheerful context, trains exactly the skill they are missing: I cannot see you, and you come back.
Announce departures, and come back. Leave the room saying you are coming back, and actually come back — after ten seconds first, then thirty, then a minute. They learn your absence has a predictable end.
A rigorously identical bedtime routine. This is not the moment to improvise. Same order, same length, same last sentence before lights out. Predictability does more than the length of the cuddle.
A comfort object, if your child takes to one — a small blanket or cloth. There is no recipe for creating one, but if they have one, leave it available at night. A safety reminder: the cot stays free of pillows, blankets and bulky soft toys until one year.
Brief, predictable visits at night. Reassure without lifting them out: calm voice, hand on them for a few seconds, then leave. Always the same. You can shorten it gradually.
What makes it worse
Slipping away. The most tempting and most counter-productive reflex. You wait until they look elsewhere, you vanish, you avoid a cry. Except you have just taught them that people can disappear without warning, at any moment. The logical conclusion, for them, is that you have to keep watch permanently — including while asleep.
Changing strategy every evening. One night you leave them, one night you lift them, one night they come into your bed. The inconsistency lengthens the period, because they cannot predict what will happen and so stay on alert.
Starting sleep training now. The worst possible timing. Asking a child to handle your absence at exactly the point when your absence is what frightens them has no chance of going well. Wait until the peak is behind you.
How long
The peak lasts a few weeks. Six to eight at most in most cases.
And it comes back. Around twelve months, around eighteen months, often after a change: going back to work, starting nursery, moving house, coming home from holiday. Each return is shorter than the last.
Co-sleeping during this period
Many families end up taking their child into their bed during these weeks, out of exhaustion. That is neither a failure nor a catastrophe — it is a decision that belongs to you.
Two things to know all the same. If you do it, do it safely: firm mattress, no duvet or pillow within reach, never on a sofa, never after drinking, smoking or taking a sedative. The official safer-sleep recommendations still apply. And know that what becomes the habit for six weeks will take an adjustment period when you want to move away from it.
The real sign of improvement
Not the number of wakings. Their reaction when you walk into the room.
At the peak, they only settle when you lift them. Then one evening they settle because you came in. Then because you spoke from the doorway. That is the progression to track — and it arrives long before the wakings stop.
Frequently asked questions
When does separation anxiety start?
Most often between seven and nine months, peaking around eight. Occasional returns are common until around eighteen months, usually after a change — going back to work, starting nursery, moving house, a holiday.
How long does separation anxiety last at night?
The peak lasts a few weeks, rarely more than six to eight. Sleep then returns to where it was: it is not a loss of skill, it is a parenthesis.
Should I slip away to avoid the crying?
No, that is the single most damaging move. Leaving without warning avoids one cry in the moment and teaches your child that people can vanish at any time — so it is safer to stay alert. Saying you are leaving and actually coming back is what builds trust.
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