Newborn to 3 years
Sleep Regression Ages
A sleep regression is a stretch of a few weeks when a baby or toddler who was sleeping well suddenly wakes more at night, fights naps or protests at bedtime. They tend to cluster around the same ages, because they follow big developmental leaps and nap changes.
Sleep regressions by age
| Regression | Starts | Lasts | Main cause |
|---|---|---|---|
| 4 month sleep regression | 3–5 months | 2–6 weeks | Sleep cycles mature |
| 6 month sleep regression | 5–7 months | 1–3 weeks | New skills and the 3-to-2 nap transition |
| 8 month sleep regression | 8–10 months | 2–6 weeks | Crawling, standing and separation anxiety |
| 12 month sleep regression | 11–13 months | 1–4 weeks | Walking and nap refusal |
| 18 month sleep regression | 17–19 months | 2–6 weeks | Independence, separation anxiety and teething |
| 2 year sleep regression | 22–26 months | 1–6 weeks | Fears, independence and big life changes |
Is it a sleep regression?
Before calling it a regression, rule out the usual suspects:
- Illness: fever, congestion, ear pulling or feeding much less. Talk to your pediatrician.
- Teething: usually a few rough days per tooth rather than weeks.
- An outgrown schedule: wake windows that are now too short often cause long bedtimes, short naps and early waking. Check them with the wake window calculator.
- A nap transition: refusing a nap is often the first sign of being ready to drop one. See nap transitions by age.
What helps with any regression
- Keep wake windows right for your baby's age, so they go down tired but not overtired.
- Stick to the same short bedtime routine every night.
- Respond consistently at night. New habits form quickly during a regression.
- Use an earlier bedtime after short naps.
- Give lots of daytime practice for new skills like rolling, sitting and standing.
Sleep regression questions
What are the sleep regression ages?
The most common sleep regressions happen around 4 months, 6 months, 8–10 months, 12 months, 18 months and 2 years.
Which sleep regression is the worst?
Many parents find the 4 month regression hardest for babies, because it is a permanent change in sleep cycles, and the 18 month regression hardest for toddlers, because of protest and independence.
Do all babies go through sleep regressions?
No. Some babies sail through with barely a change. Others have a noticeable rough patch at several ages. Both are normal.
How do I know if it is a regression or something else?
Regressions usually line up with a new skill or a schedule that needs updating. Fever, ear pulling, rash, feeding much less or seeming unwell point to illness, so check with your pediatrician.
How long do sleep regressions last?
Most last between 1 and 6 weeks. Keeping wake windows age-appropriate and responses consistent usually shortens them.