Sleep regression ages guide
Your good sleeper suddenly isn't. Find the regression that matches your child's age, what's behind it and how long it usually lasts.
- 3–5 months4-month sleep regressionThis one is a permanent change, not a phase.Lasts: 2–6 weeks for the disruption; the new sleep pattern is permanent
- 6 months6-month sleep regressionAround 6 months, babies are sitting, rolling both ways, maybe starting solids and becoming more aware of separation.Lasts: 1–3 weeks
- 8–10 months8-month sleep regressionCrawling, pulling to stand and separation anxiety often peak between 8 and 10 months.Lasts: 2–6 weeks
- 11–13 months12-month sleep regressionFirst steps and a surge in understanding language can make one-year-olds fight naps.Lasts: 1–2 weeks
- 17–19 months18-month sleep regressionToddlers at 18 months want independence, are learning words fast, may be teething molars and often feel separation anxiety again.Lasts: 2–6 weeks
- 2 years2-year sleep regressionAround 2, fears of the dark, a new sibling, starting daycare, potty training or moving to a big-kid bed can all disrupt sleep.Lasts: 1–3 weeks
What actually changes at 4 months
Toggle to compare three hours of sleep. Newborns drop straight into active sleep in long blocks. From about 4 months, sleep runs in adult-style cycles with a light phase and a brief surface every 45–50 minutes.
1 brief surfacing in 3 hours. Newborns wake mostly from hunger, not from cycle transitions.
What helps in any regression
- Protect the routine. Same steps, same order, same room every night.
- Check wake windows. Leaps often mean your child needs a longer awake stretch. Use the sleep schedule builder.
- Practise new skills by day. Rolling, sitting, standing: lots of floor time means less practice at 2 a.m.
- Comfort without rebuilding everything. Go in, reassure, keep it dull and dim.
- Keep sleep safe. On the back, own flat cot, nothing in it. Stop swaddling once rolling starts (safe sleep).
When it's more than a regression
- Sleep problems with fever, ear pain, snoring with pauses in breathing, or feeding much less
- No improvement after 6 weeks
- You feel exhausted or low for more than two weeks: tell your doctor or health visitor. Postpartum depression is common and treatable.
- Otherwise well, feeding, peeing and happy by day
- Hitting a new milestone at the same time
General guidance based on AAP, NHS and CDC advice, not a diagnosis. If your gut says something is wrong, call your pediatrician or nurse line. You never need permission to seek care.
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