You thought you were through the worst. Sleep was finally getting better. Then, somewhere between 8 and 10 months, everything fell apart again. Welcome to the 8-month regression โ one of the most disruptive sleep regressions of the first year.
Why It Happens
The 8-month regression (sometimes called the 8-9-10 month regression because it can hit anywhere in this window) coincides with several simultaneous developmental explosions: object permanence fully kicking in (baby now understands you still exist when you leave the room โ and protests), physical milestones like pulling to stand, crawling and cruising, and a major cognitive leap in understanding cause and effect.
What It Looks Like
Sudden increase in night waking from a baby who was previously sleeping well. New separation anxiety at bedtime โ crying when you leave the room that wasn't there before. Early morning waking. Nap refusal or shortened naps. All of these together, usually lasting 2โ6 weeks.
The Separation Anxiety Component
This is the part that catches parents off guard. Your baby isn't manipulating you โ they've genuinely just learned that you're a separate person who can disappear, and this is terrifying at an emotional level. Brief, warm reassurances at bedtime help. Extended negotiations and long return visits make it worse over time.
What Helps
More physical practice time during the day with the new motor skills (pulling to stand, crawling) often reduces night restlessness. A consistent, predictable bedtime routine is more important during regressions than at any other time. Hold the line on sleep habits you've established โ this is the worst time to introduce new sleep associations. The regression passes. Usually within 3โ6 weeks.