What Science Tells Us About Co-Sleeping vs. Sleep-Training

Awake again with a baby in the middle of the night, watching heinous reruns of Keeping Up with the Kardashians (What else is on a 3 am?), you dream of the nights when you slept more than 2 consecutive hours in a row.

You’re exhausted.

You’re a tired mom.

After months of sleep deprivation and looking at endless baby sleep tips, you know it’s not realistic to continue on this path of epic exhaustion. And yet, you aren’t really sure how to help both you and your baby come to terms with this whole sleep thing.

You’re friends dole out advice like tootsie rolls falling from a piñata. One friend recommends co-sleeping as the magic cure. Another friend recommends sleep training as the fix to all your sleep woes.

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But…How do you make the “right” choice?

How do you know what’s right for you and your baby?

What if there was an easier way?

What if we stopped listening to what everybody told us was the “right” thing to do?

What if we simply looked at what scientific research says about co-sleeping and sleep training and everything in between and then looked at our personal family situation to make the best decision?

Parenting is filled with fear mongering. We are all up to our eyeballs in opinions, but I think it’s time to look at the real facts and put this great sleep debate to bed once and for all.

Of course there’s a book.

I recently had the pleasure of sitting down to read The Science of Mom: A Research-Based Guide to Your Baby’s First Year by Alice Callahan. I absolutely love parenting books. And I love science. So it was a no-brainer when it came time to click ‘buy now’ on Amazon last month.

Parenting based on actual facts and the bigger scientific picture (not just one study, but a multitude) is a win-win for me. The best part of the book is Callahan’s attempt to share factual information with readers without prescribing one specific method over another. After presenting all of her research, she reminds parents to take the knowledge learned, combine it with real life, and make common sense decisions.

Now that you know the source, let’s dive in and talk about Callahan’s baby sleep research and the conclusions she draws.

What does science say about bed sharing?

Many parents choose to bed-share due to a specific parenting philosophy or because the physical closeness of the baby makes night waking easier on parents. Most studies that Callahan examined show that bed-sharing babies and moms tend to wake up more often and may experience a shorter duration of nighttime sleep than babies and moms who sleep in separate beds.

The tricky part comes as the baby gets older and enters into the toddler years. One study cited by Callahan found that 2 year olds who breastfed and bed-shared slept for an average of 4.8 hours at a time, while those who breastfed but sleep alone averaged a stretch of 6.9 hours. And 2 year olds, who no longer breastfed and slept alone, averaged a 9.5 hour stretch at night.

So what is better for babies—consolidated sleep or frequent waking and feeding?

The answer is we don’t know yet. Looking at the current evidence, there is no difference among growth rates or attachment regardless of parental choice.

Bottom line:

Whether you choose solo sleeping or bed sharing, emotional availability seems to be the most important factor towards healthy development. This means being sensitive to your baby’s cues and responding appropriately.

What does science say about bed sharing safety?

If you do choose to bed share, there are several important recommendations based on science to safely protect your child.

• Bed sharing with your baby before the age of 3 or 4 months increases the risk of Sudden Infant Death Syndrome (SIDS). It is recommended to use a bassinet or safe co-sleeper next to the bed during the initial months of life.
• Always put your baby to sleep on his back.
• Sleeping in a couch or chair with your baby dramatically increases the risk of SIDS and suffocation. If you decide to co-sleep, sleeping with your baby in a bed is the safest option.
• Avoid bed sharing if either parent smokes or drinks alcohol or the baby is premature, as this increases the risk of SIDS as well.
• Ensure your mattress is firm and flat.
• Make the bed as safe as possible:
  • Remove the mattress from the bed frame and place it on the floor and away from walls.
  • Avoid side rails since the can entrap the baby.
  • Minimize all pillows and blankets and keep them away from baby.
  • If bed sharing with a baby, keep other children, non-parents, and pets free from the bed.
  • Keep your baby warm using a safe sleep sack rather than loose blankets or a hat.

It’s important to note that outside of Western cultures, bed sharing is very common; however, their bed sharing environments are vastly different. Many countries, where bed sharing is commonplace, use a pallet or very firm futon on the floor to ensure safety.

What does science say about self-soothing?

Basically, a baby is considered a self-soother if he or she wakes during the night and is able to return to sleep independent of parental intervention. According to Callahan, “It’s as if they wake up, look around, and think, ‘Oh yes, here I am in my crib still. Nothing interesting going on here. Yawn. I guess I’ll go back to sleep.’” (p. 124).

Several studies show that when parents are given tools to help their babies gently self-soothe, babies will sleep longer and cry out for their parents less often during the night as early as a few months of age.

Best ways to help your baby learn to self-soothe:

• Laying the baby down awake, but drowsy for naps and bedtime.
• When your baby wakes during the night, wait a moment before responding, especially if the baby is making quiet noises.
• Offer your baby a special lovey. A pacifier, a knotted t-shirt, or any small comforting object that does not present a choking or strangulation hazard will work just fine. Most recommendations state using a lovey is safe around 6+ months of age. We love this one.

What does science say about sleep-training?

Depending on who you ask, sleep training involves various methods, which may be abrupt or gradual. All sleep training involves letting your baby learn to self-soothe so he or she can fall asleep without parental help.

Studies show that sleep training leads to “reduced bedtime struggles, fewer night wakings, and longer sleep for both baby and parents, better maternal mental health, and even improved baby temperament and mood.” (p. 133).

Sleep training isn’t a perfect fit for every baby and family. Science teaches us that not every baby will respond well to sleep training. As a parent, it’s important to use common sense to determine if sleep training is working for your baby, knowing when to “throw in the towel” if things are going poorly.

It’s important to note that sleep training does not eliminate night waking altogether, but rather it reduces it over time. If your baby wakes during the night and experiences a legitimate need, parents should meet those needs.

What does science say about self-soothing and sleep-training safety?

There is no scientific evidence that responsible sleep training will hurt your child. Experts and parents against sleep training often cite studies that claim sleep-training will damage or hurt your child.

It’s important to note in Callahan’s research that all of those studies are about “babies who were subjected to chronic neglect or abuse or raised in orphanages, lacking strong attachment figures. Or they’re about nonhuman primates or rodents separated from their mothers for extended periods of time. These are examples of chronic, toxic stress. ” (p. 133).

Callahan further explains that there is no evidence demonstrating sleeping training as harmful when parents utilized responsible techniques, gentle boundaries and employed positive parenting interactions.

The big picture.

This is merely a glimpse into the science behind babies, sleep and safety. The Science of Mom: A Research-Based Guide to Your Baby’s First Year goes into far greater detail, and I highly recommend diving into Callahan’s book to see the evidence for yourself, as well as doing a bit of your own research.

Baby sleep solutions are not a perfect science. Whatever sleep choices you make for your child and family, do it mindfully, lovingly and intentionally. Making responsible, common sense choices comes from listening to your gut, doing your research, understanding actual facts, and avoiding much of the negative fear mongering opinions in the parenting community.

Rest easy mama. A good night’s rest is just around the corner.

Print your free baby sleep checklist!

Chances are…you won’t remember the tips from this post. This printable simplifies it! Plus, when you grab this printable, you’ll get instant access to my free 3-day baby sleep eCourse.

Download your free printable

1. Download the checklist. You’ll get the printable straight to your inbox, plus get my Free 3-Day Baby Sleep eCourse!
2. Print. Any paper will do the trick, but card stock would be ideal.
3. Place it on your refrigerator. Use it as a quick reference and don’t forget a thing!

Grab your baby sleep checklist here!

Want more on baby sleep?

• 8 Infant Sleep Facts Every Parent Should Know
• The Newborn Routine That Will Help Baby Fall Asleep Fast
• This Baby Bedtime Routine Is Easy and Works Like Magic
• 6 Tried and True Baby Sleep Schedules That Parents Love