My baby won't wake up. When should I worry?

The question worth asking properly

When should I be worried that she isn't waking up.

It's a good question and it has a clean answer, which is unusual. The answer isn't about how long she's slept. It's about what happens when you try to wake her.

Sleepy versus difficult to wake

A sleepy baby takes some getting going. Unwrap her, change her nappy, talk to her, a hand on her chest — and she comes round, opens her eyes, and is properly there. She might be cross about it. That's fine.

A baby who is difficult to wake doesn't come round properly. She stays limp, doesn't focus, doesn't respond, or drifts straight back regardless of what you do.

Those two look similar for the first ten seconds and they are not the same thing at all. The second one is a call, whatever time it is.

What to check while you're trying

Colour — around the lips especially. Pale, mottled, blue or grey is urgent.

Breathing — fast, laboured, or pausing.

Temperature, and whether she feels unusually cool or hot.

When she last fed, and when the last wet nappy was.

Muscle tone. A floppy baby feels different in your hands and you'll know it if you feel it.

If she wakes fully, feeds, and is herself — a long sleep is a long sleep, and you're allowed to enjoy it.

If anything in the list above feels wrong, call. Out-of-hours services are there for the parent standing over a cot at 2am, unsure whether this is normal.

And if she was premature, the threshold is lower. A sleepy preemie who quietly misses feeds is a real situation rather than a theoretical one.