Sleep Regressions: What They Really Mean

If your baby was sleeping well and suddenly starts waking up more at night, fighting naps, or becoming extra clingy at bedtime, you might be in the middle of a sleep regression. The good news? These phases are completely normal, and they’re actually a sign that your child is growing and developing new skills.

Sleep regressions can cause a lot of anxiety! You hear about them and how “dreadful” they are, but what actually causes them? The truth is, sleep regressions are really progressions. They’re a natural part of your baby’s development! While sleep may take a temporary hit, with consistency, a solid routine, and strong sleep foundations, we can soften the impact and help your little one get back on track faster.

Below are the most common sleep regressions in the first two years of life, and the reasons behind them:

6 Weeks: Sleep Regression Caused by a Growth Spurt

Cluster feeds can be tough, especially when you’re just trying to settle your baby down for the night so you can get some rest. At six weeks, your baby is going through their first major growth spurt and is “tanking up” for the night. This leads to increased hunger and more frequent feedings, both during the day and overnight. Babies are also beginning to develop real sleep patterns and are becoming more aware of their surroundings. This new awareness can feel overstimulating, which may cause disruptions in sleep.

4 Months: The Famous 4-Month Sleep Regression Explained

Ah, the four-month sleep regression - I’m sure you’ve heard of this one. Newborns tend to be very sleepy due to simple sleep patterns that alternate between active (REM) and quiet sleep. Around four months, however, babies begin to develop a melatonin cycle, and their sleep becomes more structured. They now experience the same sleep cycles as adults, which include five stages (cycling between light and deep sleep). And these changes are permanent. To make things more complicated, many babies also start rolling onto their stomachs at this age — another factor that can disrupt sleep.

So, why don’t adults wake up fully when we shift into light sleep every couple of hours? Well, we actually do. The difference is that we know how to turn over and put ourselves back to sleep. This is a learned behavior, and a skill many babies haven’t mastered yet. When they shift from deep to light sleep and stir awake, instead of self-soothing, they often wake fully and seek comfort from their caregiver, usually in the form of feeding or rocking.

This is a completely normal stage of development, and one of the reasons I love helping families with sleep training around this age. With gentle guidance, babies can quickly learn how to fall back asleep independently before long-term habits set in.

6 Months: Sleep Regression from Learning New Skills

Babies love to practice their new skills when they’re alone and it’s quiet - in other words, at night, when they’re supposed to be sleeping! Around this age, your baby may be learning to roll, sit up, or crawl. Their brains are also developing rapidly, which increases their awareness of the world around them. During REM sleep, they process and consolidate all the exciting new movements and discoveries from the day. This can keep them awake at night, eager to practice.

To help, give your baby plenty of opportunities during the day to roll, sit, crawl, and explore. The more practice they get while awake, the less tempting it is to rehearse these skills at bedtime.

9 Months: Sleep Regression from Separation Anxiety

By nine months, your baby is often crawling, babbling, and hitting new developmental milestones. They are also learning about object permanence: the understanding that something still exists even when they can’t see it. Since babies don’t yet have a concept of time, when you leave the room, they may think you’re gone forever. This can cause separation anxiety, clinginess, and tears at bedtime.

Games like peek-a-boo and other object permanence activities during awake time can help reassure your child that when you leave, you will always come back.

12 Months: One-Year-Old Sleep Regression

At this age, the world is just too exciting! Many babies are beginning to talk, follow simple instructions, walk, and explore new foods. With so much going on, sleep can feel less appealing. Sleep disruptions at this stage may also be tied to teething, new routines (like starting daycare), or rapid emotional and social development.

18 Months: Toddler Sleep Regression and Limit Setting

Between 15 and 21 months, children often go through another phase of disrupted sleep. This is linked to big developmental changes, such as cognitive growth, more separation anxiety, and the transition to a one-nap schedule.

These changes can show up as increased night wakings, difficulty falling asleep, shorter naps, or bedtime resistance. Toddlers are also becoming more aware of their independence and their ability to make choices. They may think: “Wait, I get a say in this? Maybe I don’t want to sleep without Mom!”

How to Handle Sleep Regressions at Any Age

With all regressions, consistency is key. Stick with your routines and best practices, and increase feeds as needed. While your child may need extra comfort during these stages, be mindful not to create caregiver-dependent sleep associations. Adjust naps and bedtimes as necessary, and remember: sleep regressions are actually signs of progress!

If your baby’s sleep regression feels overwhelming, you don’t have to go through it alone. As a pediatric sleep consultant, I’ll help you create a plan that works for your baby, your parenting style, and your family’s needs. Together, we can get sleep back on track and bring more rest into your home.