When sleep suddenly gets worse and how to reset it without making things harder.

You had some good nights. Maybe even a run of them. Long stretches, manageable wakes, the feeling that you were finally turning a corner.

Then around three to four months everything fell apart.

This is the most common point at which parents arrive at my work. They are exhausted and confused because they had it and now it is gone.

I want to give you a straightforward explanation of what is happening. Because understanding it clearly changes how you respond to it.

What is actually happening

Around three to four months your baby's sleep architecture changes permanently. They develop adult-style sleep cycles with distinct stages of light and deep sleep. Before this point they moved quickly into deep sleep and stayed there. Now they cycle through lighter stages of sleep every 45 minutes or so and they have to transition between those cycles.

That transition is the skill they do not yet have.

At the top of each sleep cycle, they come into light sleep and briefly register the world around them. If the conditions are different from what they fell asleep with, their brain raises an alarm. Fell asleep feeding? They need the feed. Fell asleep being rocked? They need the movement. Fell asleep in your arms? They need your arms.

This is not a personality flaw. It is a neurological response to a mismatch between sleep onset conditions and wake conditions. The only way through it is to change what the conditions are.

Why what worked before is now working against you

Everything that helped in stages one and two, feeding to sleep, rocking, contact napping, was perfectly appropriate then. I am not telling you it was wrong. It was right for that stage.

The reason it stops working now is the sleep architecture change. What was a gentle shortcut to sleep has become a dependency that triggers at the top of every cycle.

The baby is not being difficult. The baby is doing exactly what their brain is wired to do. Your job now is to slowly shift the conditions so the cycle transitions happen without an alarm.

What changes nights at this stage

The reset at this stage is not about a different routine. It is about sleep onset conditions.

The goal is to shift from fully assisted sleep onset (feeding, rocking, holding until deeply asleep) toward drowsy but awake at the point of going into the sleep space. Not wide awake. Not crying in a cot. Drowsy. Calm. At the edge of sleep.

That shift does not happen in one night. It usually takes four to seven nights of consistent conditions before the transitions start to happen more independently. Some families see change in two nights. Very few see no change at all if the approach is calm and consistent.

What to do tonight

Pick your bedtime settling sequence and run it the same way. Same order, same room, same handling. The sequence does not need to be long. Nappy change, sleeping bag, three to five minutes of calm presence, then into the sleep space with a hand on the chest.

If they wake at the top of a cycle, give them sixty seconds before responding. Some will resettle. The ones who do not need you, but need calm low-input settling rather than full feeds at every wake.

Keep the environment consistent from when they fall asleep to when they wake in the night. Whatever they can see and sense at sleep onset should be the same at 2am.

Not sure if you are in Stage 3?

Answer eight questions and I will tell you exactly where your baby is and what to focus on tonight.