By a year and a half, most parents have a bedtime that works. Bath, milk, a book or two, lights out, done. So when a toddler who went down easily for months starts screaming at the cot door, climbing the bars, calling for you every twenty minutes and then waking at 5am chatty and ready for the day, it can feel like the ground shifting.
It is common enough to have a name: the 18 month sleep regression.
What is behind it
Like the 8 month regression, it is less one thing than several arriving together.
Independence. Somewhere around 18 months, toddlers discover that they are separate people with opinions, and that "no" is a word that does something. Bedtime is one of the few places they get to test it every single day. Pushing back is not bad behaviour. It is development, and it is also very tiring.
Separation anxiety again. It often resurfaces at this age. A toddler who understands more about the world also understands more about being left alone in a dark room, and may want you there far more than they did at a year.
Molars. First molars often come through somewhere between about 13 and 19 months, and they are bigger and more uncomfortable than the front teeth. A sore mouth makes settling harder, especially lying down.
The nap change. Many toddlers move from two naps to one somewhere between 12 and 18 months. While that settles, the day can end with a child who is either overtired or not tired enough, and both show up at bedtime.
What tends to help
Keep bedtime the same. The routine is doing more work than it seems. At this age a predictable sequence is how a toddler knows what is coming, and the regression ends faster when the sequence does not change. Make it calm, make it the same every night, and make the last part of it dull.
Give choices, not negotiations. A toddler fighting for control will fight bedtime less if they get some control inside it. Red pyjamas or blue. This book or that one. Walk to the bedroom or be carried. Two options, both acceptable to you. What is not on offer is whether bedtime happens.
Check the nap. An afternoon nap that ends after about 3.30pm, or runs very long, often pushes bedtime later than it can manage. If bedtime has turned into a battle, shorten or bring forward the nap before anything else.
Keep night visits boring. Go in, reassure, lay them back down, leave. Short and calm. The goal is to be reliable without being entertaining.
Hold off on big changes. This is not the moment to move to a bed, start potty training, or change rooms. A cot is a clear boundary, and most toddlers are fine in one until two or three. If yours is climbing out and could fall, safety wins and a change may have to happen, but otherwise wait until sleep has settled.
For sore gums, something cold to chew on before bed can help, and sugar-free paracetamol or ibuprofen at the right dose for their age is fine for genuine discomfort. Teething does not cause a high temperature, so if your toddler has one, something else is going on.
Twins at eighteen months
Two toddlers in one room is its own situation. At this age twins have usually discovered each other properly, which is lovely during the day and a problem at 7pm. The cot turns into a social event: chatting, laughing, throwing toys into the other cot, one climbing while the other cheers.
What tends to work:
- Stagger bedtime by fifteen or twenty minutes. Put the quicker sleeper down first, so they are already asleep when their sibling arrives.
- Separate them temporarily. If the chatting is the whole problem, a few weeks in separate rooms often fixes it outright. Most twins go back to sharing without trouble.
- Work out whose night it is. Often one twin is going through the regression and the other is just being woken up. Knowing which changes what you do. The one being woken mostly needs quiet; the one struggling needs the routine.
- Split the night by time, not by child, if you are both up a lot. Taking turns on duty while the other sleeps properly protects more rest than both of you surfacing every time either toddler calls.
When to talk to someone
It is a phase in a healthy toddler. Get advice if there is snoring with pauses in breathing, signs of illness or pain beyond ordinary teething, a high temperature, or if it goes on for well over a couple of months with no improvement. And if it is wearing you down to the point of dread every evening, that alone is a good reason to talk to your health visitor or GP. Support is part of the job, not an extra.
It is not forever
The 18 month regression is often the hardest one to live through because a toddler has so much more to say about it than a baby does. It is also, for most families, the last big one. Keep the evening steady, give them the small choices, and in a few weeks bedtime usually goes back to being the easiest part of the day.