Why Is My Baby Waking Overnight?

It’s a question most parents will ask at some point… “why is my baby waking up in the night?”

Maybe your baby was a great sleeper and now all of a sudden they are waking up, or maybe they have always had a hard time staying asleep.

We’ll break down all the potential reasons your baby could be waking up in the night, so you can play detective and start to learn how to decrease those extra or "unnecessary" wake-ups.

At What Age Should I Worry About Overnight Wake Ups?

For newborns and infants in the first 3 months, it’s important that we never try to restrict or eliminate wake ups. Newborns don't have a functioning circadian rhythm yet, and it takes closer to four months before we see baby’s sleep patterns and processes become more mature. Not to mention, they have HUGE growth demands, so if they’re waking overnight it’s likely due to hunger.

Keep in mind that any reference to age in this post refers to a baby’s “true” or adjusted age. This means that if a baby was born more than a week before their due date, it’s usually best to adjust their age based more on their estimated due date when it comes to expectations regarding being ready for reaching milestones - including sleep ones!

Why Longer Sleep Stretches Are Important

We want babies to sleep as long and as comfortably as possible in between bouts of needing to be fed. This is what we in the sleep-world like to call it “consolidated sleep”. Why do we want more consolidated night sleep you ask? Well, there can be lots of reasons for this, but from the sleep perspective, it can mean longer stretches in deep non-REM sleep.

Deep non-REM sleep is when cells rejuvenate, the body restores itself, and rebuilds strength in muscles, bones, and in the immune system. After 4 months of age, most babies are able to benefit from at least one longer stretch of consolidated nighttime sleep. This stretch usually happens during the first half of the night, and often the baby will get into a deep sleep and stay there the longest before needing to wake up, say for a feeding.

There are usually a few more sleep cycles, which are essentially periods of lighter sleep and periods of deeper sleep before Baby wakes up for the day. They may or may not wake after each sleep cycle, but that depends on the baby, much like it depends on the person. We adults also go through all these sleep cycles and sometimes we remember them, sometimes we don't. Sometimes we can just roll over, other times we have trouble getting back to sleep.

Overnight Wake Ups Potential Causes

Temperature

Comfortable temperature for sleeping is between 18 to 22 degrees Celsius, and coincidentally keeping the room around 18 to 22 degrees is recommended for safe sleep. 

Our core body temperatures lower at night to help us sleep, so sleeping in cooler rooms is beneficial. But if your baby is too cold, that can certainly cause disrupted sleep.

It is common, especially during the cooler months of the year for you to notice that your baby's hands are a little chilly when you're tending to them at night. This does not necessarily mean that they are too cold.

To check if they are too cold, place your hand between their shoulder blades under their shirt, at the base of the neck. This area is going to be more indicative to what their core body temperature is rather than their extremities.

Alternatively, your baby could be too warm, which can make them too sleepy. You can check the same way, under their shirt, and if they feel warm and sweaty, they are too warm, which can be an unsafe situation.

In the cooler months, they need one extra layer beside their pajamas. That could be pajamas with an extra onesie underneath, or perhaps a sleep sack.

Light

Too much light coming into the room is another reason your baby might be waking. Depending on the time of year, the sun may still be out at bedtime, and this is also a common reason for short, disrupted naps.

I don't usually recommend that everybody use blackout blinds for their babies to sleep because it’s not always necessary, but some definitely benefit from complete darkness. If you are looking to totally black out the room, but you don't want to invest in blackout blinds or curtains, you can try putting tinfoil around the edges of the window where light might be seeping through.

Generally speaking, just keeping things as dark as possible is a great idea, because this is what helps our bodies produce melatonin, our sleep hormone.

When you're feeding or changing your baby overnight, try to use as little light as possible if you need any at all. A nightlight or a light on in the hall may be best to keep the room dimly lit as possible. Be mindful that other things in the room like monitors and sound machines may emit light as well, which isn’t a problem unless it’s very bright or in their line of vision.

If you are trying to help your baby get sleepy or have an earlier bedtime, keep the lights dim in your home in the evening, leading up to bedtime. This can have a really positive effect.

Hunger

Hunger is a common cause for babies to wake throughout the night, and of course younger babies are going to need to feed throughout the night.

For the older babies, above eight or nine months of age, who are still feeding more than once a night, many parents worry that eliminating overnight feedings will decrease their overall consumption in the run of the day, because those babies aren't eating as well during the day. But oftentimes it's actually the opposite of what you might think; the baby's not eating well during the day, because of all the calories they're taking in overnight.

Check with your baby's doctor before eliminating any overnight feeds, but sometimes tackling the daytime feedings to ensure baby is getting enough of what they need during waking hours can help to decrease the needs overnight.

Dirty Diapers

Generally speaking, many babies will wake up because of a dirty diaper. Once they're past the early infancy stage, after those first couple of months, most babies aren't dirtying as many diapers overnight.

If you do need to change their diaper, what I like to tell parents is to go in and be a night ninja. Change the diaper as quickly and quietly and with as little light as possible, and then get right back into the feeding or helping them fall asleep or putting them back down. Changing the diapers should be very little interaction and still keeping things dark, cool, comfortable and in sleep mode.

Illness

Another, more serious reason, for waking overnight is if your baby isn't feeling well. If your baby is sick they're most likely going to be waking up more in the night and having more disrupted sleep in general, because their life is disrupted by this right now.

When your baby is sick, it’s not the time to force any kind of independent sleep or longer stretches of sleep. Be prepared for extra cuddles, feedings and be prepared for them to need help falling back asleep, even if they were sleeping independently before. They might need to take longer naps or sleep more during the day until they are feeling better.

There are also physical issues that can cause sleep disruptions. If they are mouth breathing causing them to snore, that can be a sign of enlarged tonsils or adenoids. Acid reflux is another reason that they could be having trouble getting to sleep or staying asleep.

If you suspect something like enlarged tonsils or adenoids, or acid reflux, chat with your primary care provider about treatment options.

Bedtimes

A big reason why many babies are waking up unnecessarily is actually because they're not getting to bed at the right time. An appropriate bedtime for babies over four months of age is usually anywhere between 6pm to 8pm.

What actual time your baby should go to bed at night will depend on their age and how long it's been since their last nap. If you try to keep a firm bedtime, regardless of sleep cues or wake windows can be a recipe for disaster when it comes to nighttime sleep. If your baby is overtired, it can sometimes make it hard for them to fall asleep, but it almost always makes it tougher for them to stay asleep.

So making sure your baby's on the right schedule for their age and stage is really important. Read more about why your baby might be waking up too early.

Daytime Sleep

Lastly, your baby could be waking more at night because they're not napping well during the day.

But what is napping well? For babies between 4 to 6 months of age, I generally recommend sticking to their wake windows.This might be anywhere from an hour and a half to two and a half hours as they get older.

You can also follow your baby's sleep cues, like yawning, rubbing their eyes, zoning out or having their hands around their face. If they're doing those things around that hour and a half to two and a half hour range, it can be really helpful in helping you determine when to put them down for a nap.

For babies over six months, I usually recommend having them nap around the same times every day, as it helps to get in line with their natural sleep rhythm. This changes as they grow. Wake windows get longer as the day goes on, for instance, between 6 to 8 months of age, your baby might be awake for closer to two hours earlier in the day, and up closer to three or three and a half hours towards the end of the day.

Between 9 to 12 months or older wake windows increase even more. They might be closer to two to three hours in the morning and get as long as about four hours or so towards the end of the day. Read more about naps & wake windows.

Developing Sleep Skills

There are many reasons why your baby could be waking overnight, but if you've exhausted all your resources and have eliminated any other possible reason for your baby to wake yet they are still doing it, it could be because they don’t know how to fall asleep by themselves yet.

If your baby is used to being rocked to sleep, or fed to sleep, or bounced to sleep, it can be hard for them to go back to sleep on their own when they wake in the middle of the night.

Learning to sleep independently is a skill that all babies need to learn. If you feel like you need help, this is where a sleep consultant can help! We can chat about the challenges around sleep you’ve been facing, and come up with a personalized sleep plan.