19 August 2026 · Veronica Chi
Business & Product Director · Mum of two
Why Does My Baby Cry Before and During Sleep?
Two different things get described the same way. Crying before sleep is a baby resisting the transition into it, and is nearly always about timing. Crying during sleep is usually a baby who has not woken up at all, and the right response is often to do nothing. Telling them apart saves a great deal of unnecessary intervention.
Crying before sleep
The most common cause by a wide margin is overtiredness. Past a certain point, a tired baby produces a stress-hormone surge that makes settling harder rather than easier — the wired, giggly, impossible state most parents recognise. The instinct is to conclude they are not tired enough. The opposite is true.
- Check the awake window rather than the clock. In the first six weeks it is only 45 to 60 minutes; at four to six months, one and a half to two and a half hours.
- Move bedtime earlier, by fifteen to thirty minutes, and hold it for four nights before judging.
- Watch for the early cues — staring, stilling, a first yawn, losing interest — and act on those rather than on eye-rubbing and crying, which are late.
- Shorten the wind-down if it has grown. A long routine gives an overtired baby more time to unravel.
- Reduce input in the last half hour. Dim, quiet, calm, boring.
- Check the ordinary things: too warm, wind, a nappy, still hungry.
Undertiredness exists too and is less common — usually a late nap that has crept longer, or a final awake window that has become too short. If bedtime resistance appears alongside a nap that ended at five in the afternoon, that is the place to look.
Crying during sleep
Babies are noisy sleepers. They grunt, squeak, whimper, cry out briefly, thrash and even open their eyes, all while still asleep. Around half of a newborn's sleep is active sleep — the equivalent of adult REM — and it looks nothing like the still, silent sleep adults picture.
- A cry that starts, stops and does not escalate is almost always a partial arousal between sleep cycles. Going in usually wakes them properly.
- Wait a minute or two before responding, unless something sounds wrong. Many babies resettle themselves in that window, and they cannot learn to if they are never given it.
- A cry that escalates and does not stop is a real waking and needs a response.
- Babies surface between sleep cycles roughly every 45 to 60 minutes in the early months, which is why waking often happens at predictable intervals.
- From around four months, sleep matures into cycles with lighter phases between them, so surfacing becomes more frequent rather than less. That change is permanent.
Sudden crying out in older babies and toddlers
- Teething, which disturbs sleep for a day or two around a tooth rather than for weeks.
- Illness, particularly a blocked nose, since young babies breathe through the nose.
- Developmental leaps. Rolling, crawling and pulling up all get practised at 2am, and frustration wakes them.
- Separation awareness from around eight months, which is a normal stage and passes.
- Night terrors, from around three: eyes open, distressed, not awake, no memory afterwards. Keep them safe and wait it out — comforting often prolongs it. Nightmares, by contrast, happen later in the night and the child is awake and wants you.
When to go in, and what to do
- Go in immediately for a cry that sounds different, pained or frightened.
- Wait a minute or two for the ordinary between-cycle cry.
- Keep the response boring: low light, minimal talking, same phrase, minimal handling. Interest is often what is being sought.
- Do not turn on a bright light or start a conversation, either of which ends the night.
- Feed if they are hungry. Young babies wake to feed because they need to.
What not to change
Whatever is happening, the sleep surface does not change: on the back, on a firm flat surface, in a clear cot, in your room for the first six months. Not propped, not inclined, no pillows or loose bedding, no sleeping on a sofa or armchair with them. Crying is not a reason to move a baby somewhere less safe, and reflux is not a reason to raise the cot.
When it is worth asking
- Snoring most nights, mouth breathing, or pauses in breathing.
- A cry that is high-pitched, weak or unlike their usual one.
- Arching and screaming when laid flat, with vomiting or poor weight gain.
- Sleep that has deteriorated sharply and stayed that way for several weeks with no obvious cause.
- Any temperature of 38°C or above in a baby under three months.
Questions parents ask
Why does my baby cry before falling asleep?
Overtiredness, most often. Past a certain point a tired baby produces a stress response that makes settling harder, which reads as not being tired enough. Check the awake window rather than the clock, and try bedtime fifteen to thirty minutes earlier for four nights.
Why does my baby suddenly cry out in their sleep?
Usually a partial arousal between sleep cycles rather than a real waking. Babies are noisy sleepers — around half of newborn sleep is active sleep with grunting, squeaking and brief cries. A cry that starts and stops without escalating rarely needs a response.
Should I go in when my baby cries at night?
Immediately if the cry sounds different, pained or frightened, or if it escalates and does not stop. For the ordinary between-cycle cry, waiting a minute or two often lets them resettle — and they cannot learn to if they are never given the chance.
Do babies dream?
Babies spend around half their sleep in active sleep, the equivalent of adult REM, but whether they experience dreams is not established. The noises and movements of active sleep are not evidence of dreaming, and are not a reason to wake them.
Sources
This guide is general information, written to help you understand a topic and ask better questions — it is not medical advice and does not replace your own doctor, midwife or paediatrician. Anything that worries you about your baby belongs with them.