Most advice about baby sleep is someone’s opinion. This piece is about the one change that is not.
A short, consistent bedtime routine — the same two or three calm things, in the same order, ending in the same place, most nights — is the single best-supported intervention in the whole field of infant sleep. It has a randomised controlled trial behind it, a dose-response relationship across more than ten thousand families, a follow-up trial that measured how quickly it works, and a place on the very short list of treatments the most recent systematic review classes as empirically supported.
What the trial found
In the randomised trial, 405 mothers and their children aged seven to thirty-six months were assigned either to introduce a nightly routine (a bath, a massage or lotion, and quiet activities such as cuddling or singing, with lights out within thirty minutes of the bath) or to carry on as usual. Over three weeks, the routine group’s children fell asleep faster and woke less often and for less time — and the mothers’ mood improved too. The control group did not change.
A later analysis looked at how fast this happens and found that most of the improvement in how long it took to fall asleep appeared over the first three nights. That is unusually quick for anything in this field, and it means you will know whether it is helping within the week.
The large cross-sectional study — over ten thousand families across fourteen countries — found a dose-response pattern: the more nights a week a family did a routine, the better the sleep outcomes, with a nightly routine associated with a substantially earlier bedtime, less night waking and more night sleep than none. Because that study is a snapshot rather than a trial it cannot prove cause, but it points the same way as the trial does.
Why it works
Nobody has fully unpicked the mechanism, and — worth saying plainly — nobody has tested the ideal length or the ideal order of the pieces. The most likely explanation is the simplest one: a predictable sequence signals what is coming, lowers arousal, and gives the baby a set of cues that they learn to associate with falling asleep. The consistency seems to matter more than the content.
How to build yours
Keep it short: twenty to thirty minutes is plenty, and a newborn’s version can be five. Pick two or three calm things — a bath if you like it (it is not required), a change and pyjamas, a feed, a book or a song — and put them in the same order every night. Finish in the sleep space, not somewhere else, so the last cue is the crib. Use the same few words at lights-out.
Where you put the feed depends on your goal. If you are happy feeding to sleep, and especially under six months, leave it at the end. If you would like to loosen that association over time, move the feed earlier in the routine and let the book or song be the final step, so the last thing your baby experiences before sleep is not the feed.
Then hold it steady. Consistency across the week matters more than perfection on any one night, and travel, illness and a new tooth will all try to knock it over. The routine is the thing you keep constant while everything else moves.
One honest caveat
A routine changes how bedtime goes — how long settling takes, how the evening feels, how much the night is interrupted. It does not, on its own, change how much a baby sleeps in total by any large amount; almost nothing does. If your measure of success is hours on a chart, you will be disappointed by every approach. If your measure is a calmer evening and fewer times you are up, this is where to start.