The 4-Month Sleep Regression. Add that to the list of phrases you had never heard before you became a parent. What exactly is the 4-month sleep regression and how can you best move through it without losing too much sleep and sanity? 

Infants usually experience multiple sleep regressions in the first year of life, but the 4-month regression sticks out as the most challenging. It’s actually poorly named, as it’s not a regression, but a permanent shift in how your baby sleeps.

During this phase, a baby’s sleep changes to become more adult-like, and that’s why (for many babies), it results in more night wakings. Around 12 weeks old, a baby starts to develop their own circadian rhythms, which helps them differentiate between day and night. This change means that instead of moving seamlessly between light and deep stages of sleep throughout the night, your baby now has a more mature sleep cycle that lasts about 30-45 minutes.

Instead of easily transitioning from light sleep back into a deep sleep, your baby is now aware enough to notice a change in their environment. If they are used to falling asleep while feeding or being rocked in your arms when they lightly arouse between sleep cycles, the surprise of being in an unfamiliar environment results in a full waking. They want their original sleep conditions back! Enter Mom or Dad — going in to rock, feed, or pop a pacifier back in. Your 3-5 month old might go from sleeping 5-8 hours at night to suddenly waking every 1-2 hours. Not fun for anyone.

So when does this regression end? Some babies manage to fly right through this developmental milestone without many hiccups while others really struggle to learn how to fall asleep on their own, and will continue to protest until their parents come in to help.

The best thing you can do to manage the 4-month sleep regression is to help your baby build independent sleep skills by working to strategically eliminate certain sleep props. A sleep prop is anything that helps your baby to fall asleep. The props that typically play a role in night wakings are those that can’t be present throughout the entire night. Examples include feeding to sleep, being bounced or rocked, and a pacifier (if the baby is too young to reinsert it themselves).

Keep in mind, there are plenty of positive sleep props out there! These are the props that are safely present in your little one’s sleep space all night long. Examples include darkness, a sleep sack, white noise, or a lovey (for a baby 12 months and up). We definitely want to use these to our advantage to optimize the baby’s sleep environment.

So how do we eliminate the problematic sleep props? Start at bedtime, by putting your baby down awake and having them fall asleep in the same place you want them to be sleeping throughout the night. There are different methods for teaching independent sleep — some more gradual than others. Typically, the more gradual and gentle the sleep training method, the longer it will take. It’s important you feel comfortable with whatever method you choose, and that you have realistic expectations about the process. Also, be sure that you and your partner are on the same page before starting. No matter what method you are using, be consistent and stick with it. Once your baby feels secure in their own space, the night wakings will diminish!

During the day — focus on providing your baby with lots of opportunities to fill their calorie cup. Make sure they are taking in frequent and effective feeds throughout the daylight hours so they aren’t dependent on their night wakings for nutrition. If you think your baby is waking during the night out of habit and not because of hunger, don’t respond with a feed. Staying consistent will help get you and your baby get through this regression!