Just when sleep had finally found a rhythm, your 8-or-9-month-old is suddenly fighting bedtime, waking overnight, or standing in the cot at 3am looking equal parts proud and outraged. If that's your week, you're in one of the most common — and most misunderstood — sleep phases of the first year.

Why it happens now

Unlike the 4-month change, which is about sleep cycles maturing, this one is mostly about everything else your baby is learning at once:

  • Big motor leaps. Crawling, pulling to stand and cruising are thrilling — and the urge to practise doesn't switch off at night. Many babies wake mid-cycle and immediately get up to rehearse.
  • Separation anxiety. Around this age babies truly grasp that you exist when you leave the room — and mind very much. Bedtime is the biggest separation of the day.
  • Naps in flux. Many babies are moving from three naps to two, and an overtired or undertired baby sleeps worse at night.
  • Often teething, too. New teeth around this age can add a tender night or two on top.

What it looks like

  • Bedtimes that suddenly involve protest, tears or gymnastics
  • New night wakings — often with standing, crawling or calling for you
  • Short or skipped naps, especially the third nap fading away
  • Extra clinginess at sleep times (and often at daycare drop-off)

Most families find it lasts somewhere between 2 and 6 weeks.

What helps

Riding out the wobble

  1. Give lots of daytime practice for new skills — a baby who has crawled and pulled up all day has less to rehearse at 2am.
  2. Keep the bedtime routine exactly the same, calm and predictable — familiarity is what a separation-anxious baby needs most.
  3. At night, offer brief, low-key reassurance: a quiet voice and a gentle pat, then give them a chance to resettle.
  4. Practise 'peekaboo separations' by day — leaving and returning cheerfully teaches that you always come back.
  5. If your baby stands in the cot and can't get down, practise sitting-back-down during play; until then, calmly help them down once and keep it boring.
  6. Protect day sleep: hold two naps and watch wake windows (roughly 2.5–3.5 hours at this age) so overtiredness doesn't pile on.

Try not to introduce a brand-new habit you don't want to keep — like reinstating a 3am feed that was long gone — but don't agonise if survival mode wins some nights. You can always steer back once the phase passes.

Keep sleep safe as skills change

A baby who can pull to stand changes the safety picture:

  • Drop the cot base to its lowest setting as soon as your baby can sit or pull up.
  • Keep the cot clear — no pillows, bumpers or toys they could climb on or burrow into.
  • Keep putting your baby down on their back; once they can roll both ways, they can stay in the position they choose.
  • A well-fitted infant sleeping bag is still fine at this age — and has the bonus of discouraging leg-over-the-rail climbing.

When to check in with someone

This phase is normal, but talk to your GP or child-health nurse if:

  • The wakings come with fever, ear-pulling, breathing trouble, or your baby seems unwell rather than busy
  • Sleep doesn't begin to improve after about 6 weeks, or things feel like they're getting worse
  • Your baby seems to be losing skills they had, or you're worried about their development
  • You're running on empty — persistent low mood or anxiety in you matters just as much

Hold onto this: a baby who's too busy learning to sleep is a baby who's learning brilliantly. Keep things calm, safe and predictable, and sleep almost always finds its way back — usually with a new trick or two performed from the cot.