The Nine-ish Month Sleep Regression: What is it and what can be done about it?

The Nine-ish Month Sleep Regression: What is it and what can be done about it?

Every time you think have your baby’s sleep figured out, it will change. Most of this change is positive, with sleep gradually improving with age, but there are a few notable bumps in the road that can cause trouble. One of these is the “9-(ish) Month Sleep Regression”, dubbed so by us because it can happen anywhere between 8-12 months. For most babies it hits right around the 9 month mark. This sleep regression is different than the four month sleep regression, where the architecture of sleep itself was changing and maturing. This sleep regression is associated with developmental milestones.

When babies have a true regression, things may get better after a rough week or two, or you may find yourself stuck in a bad pattern that will only get better with intervention. The key to getting back on track quickly after a regression depends on how you interact with your baby during this tricky time.

The Science

Right around the 9-month mark babies go through an explosion of development. It’s often the time that separation anxiety hits and it’s also a time where babies tend to get more verbal and physical. Each of these cognitive and physical milestones can cause sleep disruption, but when they coincide, your baby’s sleep habits may abruptly change (see motor skill milestones blog here). When your baby starts to experience separation anxiety, it means that she understands that when you leave the room you are still around, but not immediately available. Most babies would prefer to have their parents nearby all of the time when going through this phase of development.

It’s important to note that not every baby will go through this separation anxiety-related sleep regression and some babies don’t have very severe separation anxiety. Typically the stronger the separation anxiety, the more pronounced the reaction you will get when you try to leave your child’s room at bedtime or nap time.


Need More Help?

We offer several options for optimizing your child's sleep:

SLEEP TRAINING CLASS (for well babies 6-15 months)

PHONE CONSULTATIONS (with one of our sleep experts)

THE SECRET TO NAPS (downloadable e-book)


How do I know if my baby is going through separation anxiety?

How do I know if my baby is going through separation anxiety?

The easiest test of whether separation anxiety is likely the cause of your baby’s sleep disruption is to assess her response when you walk out of the room while she is playing during the day. If she was content playing on her own when you were in the room, but cries when you leave the room, then she is probably going through this phase.

What happens to sleep during this time?

What happens to sleep during the 9 month sleep regression?