When Do Babies Sleep Through The Night?

When Do Babies Sleep Through The Night - Header Image

Key Points

  • Parents report night waking and crying as a problem with 20-30% of infants
  • Babies may sleep through the night from 3 months, or 5-6kg
  • For babies to sleep through the night, they need hunger needs met, the right sleep environment and to be able to self-settle upon waking between sleep cycles

I’d be surprised if there’s a question asked more by new parents than “when do babies sleep through the night?”

Some are blessed with babies that sleep well from very early on - and stay that way.

But, for plenty of parents out there, a full-night’s sleep seems like a far-off dream. In fact, parents report night waking and crying as a problem with 20-30% of infants.

In this blog, we’re going to look at what it really means for a baby to “sleep through”, the potential factors that need to fall into place to answer “when do babies sleep through the night”, and perhaps most importantly, why you shouldn’t stress if they just won’t sleep through.

What is “sleeping through” really?

When you hear someone’s baby is “sleeping through” a few thoughts might go through your mind. Like:

“They’re so lucky”

“How did they get their baby to do that?”

“When will my baby sleep through the night?”

“What I wouldn’t do for a solid 8 hours sleep”

You’re probably making the assumption that their baby is sleeping (without waking) from the time they are put down for bed, to the time they should wake up. Or you might assume they are at least sleeping for the same 8-hour block as their parents.

Tired Father Sleeping with Baby

But, the thing is, everyone’s interpretation of “sleeping through” can look slightly different. And in many cases, “sleeping through” is simply classed as having one longer stretch of sleep that may only be 5-6 hours.

It’s important to keep this in mind when you hear stories about people’s success with sleeping. And remember that people may embellish their sleep success stories too!

You should decide what sleeping through successfully means to your family. It can certainly help keep those night wakings in perspective if you view sleeping through the night as achieving a solid 6-hour block of sleep, rather than a 12-hour one.

What causes night wakings?

There are many factors that can cause babies to wake in the night. Some of these are biological, in order to help them survive, like hunger, or being too hot or cold for instance. Others are environmental, that may be causing baby to wake when they don’t biologically need to. Night waking causes include, but are not limited to:

  • Difficulty linking their sleep cycles
  • Hunger
  • Too hot/cold
  • Disruptive noise
  • Intrusive light
  • Moro reflex in young babies
  • Too much day sleep
  • Separation anxiety

We take a look at a few of these below and how they may impact on your bub’s sleep.

Understanding sleep cycles

Throughout this blog, we’ll be referring back to baby sleep cycles, so it’s important you have a basic understanding of how they work.

Compared with adults, babies naturally have lighter sleep. This is because more of their sleep time is in an active sleep state, rather than a quiet sleep state.

Newborns have repeating sleep cycles of light to deep sleep every 20 minutes or so. But, for older babies, this is more like 30 to 50 minutes. Just like we do, babies wake briefly between sleep cycles.

If they don’t know how to re-settle without your help, or if everything isn’t as it was when they fell asleep (for instance, you aren’t in the room, or they have been transferred elsewhere) they will cry out and need your help back to sleep. That’s why it’s common to hear about babies who wake and need to be settled every 30-60 minutes.

Meeting hunger needs

Generally, it’s said that babies should weigh around 5-6 kg or be at least 3 months of age to sleep through the night (6-8 hours). As babies grow, so does the capacity of their stomach to hold enough nourishment to get them through that period without waking up hungry. But, it is important to remember this is just a general guide and every baby has different needs.

Of course, it also follows that you should feed your baby close to bedtime to help them sleep for the longest stretch that they can manage. It’s very natural to feed your baby to sleep. There is nothing wrong with doing this, especially in that fourth trimester. However, some sleep experts suggest that this doesn’t help baby learn to fall back to sleep on their own during brief night wakings.

There have been studies that show that breastfed babies are likely to wake more in the night. This is for two reasons in particular:

  • The composition of breastmilk requires infants be fed more frequently to ensure growth
  • To maintain a continuing supply of breastmilk, frequent stimulation is required

This may change after 6 months of age and when the baby is well-established on solids, with this study showing no difference between the amount of night wakings of breastfed and formula-fed babies. Night wakings and night feedings were found to decrease with age between 6-12 months. But interestingly, the same study found that “infants who received more milk or solid feeds during the day were less likely to feed at night but not less likely to wake.” This goes to show that meeting hunger needs is only one component of “sleeping through”.

Creating an ideal sleep environment

What conditions do you need in order to sleep well? The right temperature, comfortable clothing and bedding, feeling safe, darkness. Does that sound about right? So, it comes as no surprise that babies have similar needs.

Unfortunately, it can be easy to fall into habits that help us feel more secure as new parents, but actually disrupt a baby’s sleep environment. For instance, if you’ve been sleeping with a lamp on so that you can always see your baby is ok, that light could very well be keeping them awake between sleep cycles.

Here are some ways to help your little one feel secure and sleep well.

Swaddling/sleep sack

Swaddling with arms in, is recommended up until baby can roll. Swaddling helps prevent your bub from waking themselves up with the Moro (startle) reflex that they have from birth to about 4-6 months of age. It also helps recreate womb-like safety.

Once baby is showing signs of rolling, then sleep sacks with the arms out are recommended.

The good news is, the companies selling these products provide guidelines you can follow, for how to dress baby according to room temperature and the warmth level or TOG rating of the swaddle/sleep sack.

White noise

White noise is a must when creating your bub’s ideal sleep environment. Not only can it help them fall asleep initially, but it’s also helpful during those brief night awakenings, helping them fall back asleep gently, and potentially without your assistance. White noise that is rumbly and continuous tends to work well.

Babies can easily be woken up from an active sleep state (which they have a lot of). So, white noise can also help to mask disturbances like doors opening and closing, dogs barking or other household sounds.

Safe sleep space

Of course, a safe sleep space is non-negotiable to protect against SIDS. We recommend you read more about this here.

When do babies sleep through the night: The issue of parental involvement

It’s a fine line, making sure the baby's physical and emotional needs are met, without overstepping the mark where your involvement can actually start to cause sleep problems.

How babies are settled to sleep is a contentious topic and there are many books and programs out there, each claiming to show you how it’s done. After all, the process of settling to sleep is an important component of answering “when do babies sleep through the night?”.

We’ll share with you what the research says about how actively parents should be involved with baby sleep. Although of course, we leave the decision of how you settle your baby to sleep and respond to their cues entirely up to you as the parent. This is highly individual and depends entirely on what you are comfortable with.

One studyof first-time parent couples from birthing classes taught behavioural strategies for baby sleep to a “training” group. Another group received only personal contact, no behavioural training (the “control” group). It was found when the infants were 6-9 weeks old that the “training group parents awakened and responded less often to infant signaling and reported greater parental competence.” These babies showed significantly better sleeping patterns than those in the “control” group.

Similarly, a systematic review of the literature supports the argument that “parental behaviours are the most immediate and direct factor influencing infant sleep-wake behaviours”. The evidence showed that low parent involvement helps babies learn how to self-settle and regulate their sleep-wake behaviours.

So, what classifies as parent involvement in these instances? Examples include:

  • Rocking or feeding to sleep
  • Parental presence to fall asleep
  • Transferring the baby to their cot when already asleep

These factors are associated with more night wakings and shorter sleep duration because when babies wake at the end of sleep cycles, they need the same method to be present to help them get back to sleep - they don’t know how to do it on their own.

However, the argument can be raised that when low parent involvement is taken to the extreme - such as with extinction or cry-it-out methods, there’s an imbalance in meeting the needs of babies. This Australian theoretical review suggests that middle ground should be sought, and that leaving a baby to cry isn’t the only way of teaching them to sleep. In fact, methods such as patting to sleep can be just as effective.

When do babies sleep through the night? The verdict

So, we’ve heard that babies can sleep through (from a physiological standpoint) from 3 months of age. However, this study of babies aged 6-12 months were regularly waking at least once a night. Unfortunately there is no magic number to answer your question of when do babies sleep through the night?

It is highly individual. But, as you’ve seen in this article, there are many ways to reduce the night wakings and help your little ones sleep better.

Try not to chase perfection. It’s very easy to feel like you’re failing as a parent if you haven’t been able to “train” your baby to get the sleep they need.

But, you certainly aren’t failing. It might be time to try something new, or time to shift the goal posts of what “sleeping through” means to you.

And even when your baby does start sleeping through the night, be prepared for instances that might cause temporary disruptions, like illness and of course, the dreaded teething.

All you can do is set them up for good sleep and see what follows.