Of the many milestones that come with having a baby, one of the more relieving ones is when your baby starts sleeping through the night. But whether you’ve already reached that milestone or have a little one who’s a consistent sleeper, there may be periods where their sleep quality seems to go backwards. This is called “sleep regression.”

These sudden, sometimes extended returns to multiple nighttime wakings, increased fussiness and disrupted schedules can be discouraging and draining. But the good news is that these wakeups are usually completely normal and can even be a sign that your baby is learning something new.

Keep reading to learn what’s going on when a sleep regression happens and what you can do to help your little one sleep soundly again.

What a sleep regression actually is

Sleep regression is the common term for sudden periods of unexplained disruption in a baby’s sleep schedule. However, these kinds of disruptions are thought to be caused by physical or mental development. There isn’t actually any regression happening when it comes to the health of your child, and it’s generally not a sign that anything’s wrong.

For example, many parents experience a common sleep regression that takes place when babies are around 4 months old. It may come earlier, later or may not seem to happen at all. Well, this covers the same period in which babies start to develop a more mature sleep cycle: they begin distinguishing between day and night, start consolidating their sleep and begin to cycle between different depths of sleep. This change in their sleep means that your baby is growing up. But these changes take time, and every baby is different. As they mature, it may appear as though your baby’s ability to sleep through the night is going backward.

Other possible causes of sleep regressions may include:

• Motor skill development – Babies are curious about and eager to interact with their environment, so gaining more control over how they move their bodies can be exciting enough to disrupt their sleep. You may notice sleep regressions that coincide with your baby learning to do things like roll over, crawl or stand up.
• Object permanence – As they learn that things continue to exist even when they’re out of sight, your baby may resist sleep in an effort to stay involved in the action.
• Separation anxiety – Part of learning object permanence is your baby learning that you and other caregivers are still around when not in the room. Knowing this, your baby may try to call you back in rather than settling on their own.

How long sleep regressions last

Sleep regressions can last anywhere from a few days to several weeks – however long it takes for your baby to become accustomed to the changes they’re going through.

Common sleep regression ages for babies and toddlers

Since sleep regressions seem to be related to development, every baby will experience them differently. Some babies may show no signs of sleep disruption beyond their regular nighttime wakings. Other babies may seem to have regressions at some, but not all, of the expected times. There’s no guarantee that your baby’s development will follow an exact schedule. Generally speaking, the most common ages for sleep regressions appear to be around:

• 4 months old – Your baby’s sleep patterns start to mature, adopting stages and cycles like those of an adult, causing disruptions in their typical routine.
• 8 months old – Between separation anxiety, teething and nap transitions, your baby will have a hard time letting you out of their sight when it’s time to sleep.
• 12 months old – With increased mobility at this stage, your baby may be more interested in exploring through crawling, standing and walking instead of laying down to sleep.
• 18 months old – Your baby is now a toddler, and they may start experimenting with their independence. “No” can become a common word they’ll use at bedtime. Your toddler asserting their own ideas about their schedule, coupled with another nap transition, can make this a difficult stage for sleep.

How to handle sleep regressions

There’s no sure way to prevent sleep regressions. Changes in your baby’s sleep patterns are a normal and natural part of their growth. If you have a baby with colic, this may sound familiar – sometimes you may just have to wait it out. But there are things you can do that may help manage sleep regressions and help your baby settle more easily in general.

Set a consistent sleep routine

Once your baby is a few months old, you can take advantage of their maturing sleep patterns by creating a relaxing bedtime routine. This could look like a bath, feeding and quiet reading or cuddling in the 30-45 minutes before lights out. During this time, it can also help to reduce sources of stimulation by dimming lights and lowering your voice.

Consistency is key: repeating the same steps around the same time every night will help your baby learn to associate them with sleep. For the same reason, it's also important to start putting your baby in their crib when they’re showing signs of sleepiness, but before they’re asleep entirely. This will help your little one learn to fall asleep on their own.

Set boundaries on waking episodes

Even with a solid bedtime routine, your baby is likely to wake in the night. To reinforce the idea that nighttime is for sleep, try to address wakings with minimal direct contact or other disruptions. In some cases, it may be a good idea to give your baby a minute or two to see if they’ll self-soothe before stepping in to soothe them yourself.

If your baby is waking because of something physical like hunger or needing a diaper change, address that need quietly and quickly. And remember to keep the lights as low as possible. If you’ve ruled out physical needs, try to comfort your baby without taking them out of their crib.

When to see a doctor about sleep regressions

Disruptions in your baby’s sleep routine can be tough, but they’re temporary. Your baby’s got a lot of growing to do, and they are only responding to their body’s signals.

Talk to a doctor if your baby’s sleep disruptions are paired with additional symptoms such as pain, fever or illness, or if your baby’s night wakeups are affecting your ability to look after yourself or your baby. An expert can offer recommendations for creating or reinforcing sleep schedules, helping your baby settle and looking after your own mental health until your baby is sleeping more soundly.