Infant Sleep Research: Bedsharing, Self-Soothing, and Sleep Training
This is the fifth post in my sleep series. In my last post, I discussed how my view of infant sleep has evolved to be more inclusive of a wide range of solutions that can work in different families. In this post, I look at what the research tells us about infant sleep across the spectrum of nighttime parenting philosophies.
[Please note: It is beyond the scope of this article to discuss the bedsharing/crib/SIDS/suffocation debate, but suffice it to say that parents should pay careful attention to making baby’s sleep environment safe, whether the baby bedshares or sleeps in a crib.]
Bedsharing Infant Sleep
Let’s say that you choose to bedshare. You feel that the best place for your baby is right by your side, in your own bed. (I use the term “bedsharing,” because the more commonly used “cosleeping” can also mean sharing a room but sleeping on separate surfaces.) Many parents choose to bedshare because it just feels right, even if they had carefully prepared a crib before the baby’s arrival. BabyC slept in my bed for a couple of weeks early in her life, though it was not my plan and ultimately ended up not being the choice that Husband and I made. Still, in those weeks, I felt a real shift in my bond with BabyC. It certainly made breastfeeding during the night easier, and it was sweet to wake up and watch her sleeping next to me. I understand the choice to bedshare, and I think that for many families, it can have numerous benefits. These benefits are not well-defined by research, however. For example, I have yet to find study that investigates if bedsharing actually increases infant attachment.
Bedsharing is common around the world. In an international survey of parents of over 29,000 infants and toddlers, bedsharing was the norm in Asian cultures, while most Caucasian parents put their babies to sleep in a separate room . Across cultures, babies that bedshared went to bed about 1 hour later, woke their parents more during the night, and slept about 1 hour less per night.
Several controlled studies give us a more detailed and slightly different look at the sleep patterns in bedsharing infants, though they are all limited by very small sample sizes. One study used video recording to observe 18 age-matched infants (3-15 months) sleeping in their own homes and found that bedsharing babies slept just as much as solo-sleepers . The bedsharing babies did wake more often during the night but transitioned back to sleep faster than the solo-sleepers, so both groups of babies spent about the same amount of time awake and asleep during the night. This study did not report how often the baby actually woke the parents, and it is likely that the solo-sleeping infants transitioned back to sleep on their own without calling for help for at least some of their wakings.
Dr. James McKenna and colleagues looked closely at the sleep of 35 mama-baby pairs (11 to 15 weeks old) in a laboratory setting. They found that both mothers and babies woke more often when they bedshared, and these arousals usually overlapped . These data led them to hypothesize that bedsharing could be protective of SIDS, since it encourages more frequent arousals than solo sleep. This is an intriguing and plausible hypothesis, but it has not been further investigated. Another laboratory study of breastfed babies found that those that bedshared nursed more often and for longer time during the night than babies that slept alone [4, 5].
Many of the differences in sleep patterns between bedsharing and solo sleeping infants likely occur because bedsharing infants may not learn to self-soothe at night until later in childhood. After all, Mom or Dad are almost always there to help them transition to sleep at bedtime and during normal night wakings. It is not clear if the differences in sleep patterns have any significant effect on the health or well-being of infants one way or the other. There is SO much room for more research on cosleeping and bedsharing. For example, why do some bedsharing babies wake once per night and others wake every hour? Does the more frequent waking make them less rested than babies with more consolidated sleep, or do bedsharing babies get the sleep they need? Does more frequent night nursing improve their nutrition or breastfeeding success?
Regardless, when parents make an intentional choice to bedshare, they are likely to accept frequent night wakings as a natural part of parenting. Bedsharing and the associated night wakings are more likely to be seen as a problem in a family that really doesn’t want to bedshare but takes the baby into bed during the night out of desperation.
Solo Infant Sleep
Now let’s say that you prefer for your baby to sleep in her own bed. You also probably want her to have a nice consolidated night of sleep without needing much of your comfort, because providing comfort in the middle of the night is much more disruptive if you are sleeping in a different bed or a different room from your baby. Of course, if she really needs to be fed, you’re happy to do that, and if she isn’t feeling well, you’ll be there for her. However, you don’t want to have to rock her back to sleep every time she has a normal night waking. You hope that she can transition back to sleep on her own without asking for your help. As I explained in my previous post, she needs to learn to self-soothe.
In an ideal world, babies learn to self-soothe by being given gradual opportunities to try it out. Several randomized controlled trials have shown that when parents were counseled about strategies to encourage self-soothing in their babies – like putting the baby down drowsy but awake and not jumping up to intervene at every little peep in the night – their babies learned to self-soothe and sleep longer at night from a young age [6, 7]. A soothing bedtime routine can also help form healthy sleep habits early on .
What do you do if your baby doesn’t learn to self-soothe using these early strategies (or if, like me, you disregard them)? At some point, most babies who sleep alone but don’t know how to self-soothe will start to have more difficulties with falling asleep at bedtime and frequent night waking, as we found with BabyC. In some families, night wakings are not a huge problem, and parents simply cope with them. In others, they cause chronic sleep deprivation that becomes a health concern for the family, and this is the point when most families consider sleep training.
All of the various sleep-training methods were developed to help babies learn to self-soothe, and the research shows that these methods are effective. In a 2006 review, Jodi Mindell and colleagues reviewed 52 studies, published between 1970 and 2005, of the major sleep training methods . Eleven of these were randomized controlled trials, including a total of 1,135 children between the ages of 6 weeks and 5 years. A few more controlled studies have been published since then, and I’ve included these in my summary.
In study after study, sleep training has been found to have the following outcomes, usually within 1-2 weeks:
- Reduced bedtime struggles, fewer night wakings, and longer sleep for baby, and consequently, for parents [9, 10].
- Improved maternal mental health, with fewer moms being clinically depressed [11, 12]. In some studies, parents have also reported less parenting stress and greater confidence, as well as more marital satisfaction [7, 9, 10].
- Improved baby temperament and mood, as reported by parents [13-16], usually the mother. Of course, a mother is not exactly the most objective judge of her baby’s behavior, but I would argue that she is the most important one. Still, it is difficult to know why babies were rated as less irritable and more secure following sleep training. It could certainly be that they were getting more and better sleep, directly reducing crankiness. It could be that mom was better-rested and thus more tolerant of fussiness and focused on positive interactions with her baby. Or, it is possible that baby’s self-soothing skill resulted in better self-regulation during the daytime, too. Whatever the cause, this is a good thing for the mom-baby relationship. Furthermore, of all the studies of sleep training, not a single one has identified a negative effect on babies’ behavior or relationship with caregivers.
Several studies have followed up on children one year after sleep training. By two years of age, the sleep-trained children were still sleeping well, but the control kids were, too [16, 17]. The parents of the control children may have done some type of sleep training in the intervening time, or their kids might have just started sleeping better on their own. And a few kids, whether sleep-trained or not, were still struggling with sleep.
The major sleep training methods that have been tested in controlled trials are Unmodified Extinction (child put to bed awake and no comfort offered if he cries); Graduated Extinction (parents check periodically and briefly comfort the child, also known as the Ferber Method or controlled crying); and Extinction with Parental Presence (parent “camps out” with baby while he cries, gradually withdrawing presence).
So, among these methods, which is the best? They all work. There is no evidence to suggest that any one of these interventions is more effective than the next. This is not surprising, since all of these methods teach children to self-soothe. This is good news for parents, because it means that they can choose from a range of methods to find the one that is the best fit for their family.
Among all the many guides to infant sleep on the market today, there are endless variations on sleep training that have not been directly tested. Many of them offer methods that are more gradual and emphasize more parental presence (for example, the Sleep Lady Shuffle, The Baby Whisperer’s pick up/put down method, and variations in the No-Cry Sleep Solution). This idea is appealing to parents, because we all hate to hear our babies struggle and cry. While these methods have not been directly tested in controlled trials, the reported success of “Extinction with Parental Presence” indicates that these probably work as well. Again, as long as the baby learns to self-soothe, he’s going to be better prepared to sleep well on his own. However, the process may be slower, and in some babies, it may be more frustrating to have the parent present but not offering soothing. Still, I think it makes sense to consider trying one of these methods, with the idea that parental presence may make the transition less stressful to the baby.
Although there are plenty of studies on sleep training, there are some major gaps in the research. Most importantly, we know very little about how babies respond to sleep training at different ages and developmental stages. Sleep training has been tested on young infants, but many studies also included toddlers and preschoolers, and the results were averaged together for all children. More recent studies have specifically targeted 6- to 12-month-old infants [10-12]. Several parental education studies targeted very young infants with self-soothing strategies but were not explicit about how they advised parents to handle crying [6, 7, 18]. Babies make huge developmental leaps in the first few years of life, and these developmental changes certainly influence how the baby feels and thinks about sleep training and, ultimately, the success of sleep training . For example, a baby might sail through sleep training with little stress at 6 or 12 months, but try it at 9 months, when most babies experience separation anxiety, and after a lot of crying, you might decide that your baby is one of those that simply won’t sleep on his own! And some babies, regardless of age, just might not cope well with separation or sleep training. More research is needed to help identify these babies so that parents can be encouraged to try alternate strategies.
Finally, the research has failed to directly address parents’ greatest concerns with sleep training: How stressful is sleep training for my baby? Will it make my baby less attached to me? These are really important questions, and I will do my best to address them in my next post.
Ultimately, the best sleep solution to get you through these early years of parenting is the one that is most sensitive to the needs of your child and your family. If you think that bedsharing will make you a more sensitive parent, but you hate bedsharing and feel resentful of broken nights of sleep, then it probably isn’t the right answer for you. If you think that your baby should sleep in her own bed but feel guilty about it and wish you could snuggle with her every night, well then, it may be time to reevaluate that choice as well.
I always love your comments about what worked and what didn’t to help everyone in your family get enough sleep. I’m especially interested in hearing from people who tried a more gradual method of helping their babies learn to sleep on their own. Anyone have experiences or advice they’d like to share?
Check out other posts from my infant sleep series:
- The Cry-It-Out Controversy and My Family’s Sleep Story
- Why Sleep Matters to Babies and Parents
- The Importance of Self-Soothing to Infant Sleep (and how to support it!)
- Sleep Solutions for Every Baby
- Helping Babies Cope with Stress and Learn to Sleep
- 6 Little Secrets of a Sleeping Baby
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