The basis of all "sleep methods" is the assumption that babies are supposed to sleep all night without waking. This is a fundamental misunderstanding of sleep in general and infant sleep in particular. Do you ever wake up at night? Many studies have shown that infants and young children normally wake at night, and this message is being lost in our education of new parents. Those who have babies who sleep without crying all night are eager to tell everyone about it, probably because it has come to be a sign of good parenting. This leads to other parents who have babies that wake up (the majority) to feel they are doing something wrong and that their child has a "sleep problem." But waking up at night is not only normal, it's protective! Deep sleep is part of SIDS, where a baby just stops breathing and doesn't wake up.
Another assumption is that a baby who wakes at night will cause the parents to sleep less. But research into co-sleeping showed the opposite. The parents who sleep in the same bed with their babies got the most sleep and breastfed longer (formula feeding is a big risk factor for SIDS, also). That goes against sleeping advice from the AAP (American Academy of Pediatrics), but it leaves parents sleep deprived with the only option then of leaving a baby to cry. (By the way, putting a baby alone in a room is also against the AAP advice!) The Academy of Breastfeeding Medicine has advice for parents who need sleep but don't want to leave a baby alone.
As a Certified Breastfeeding Specialist, I also couldn't help wondering about the assumption that these babies were not hungry and that preserving both the mother's milk supply and her delay of fertility was unimportant. I realize that not everything can be studied at once, but were any of these babies breastfed and was their growth being monitored during these periods of crying and lack of milk?
Problems with this study
First of all, this is an extremely small study. Should 43 Australian babies guide "normal" and "safe" for all other babies? These 43 babies were split into 3 groups, so each group was less than 15 children! Can this even be considered a legitimate study with such a small sample size? And why did the media run to pick it up and report it? Probably because they know thousands of tired parents will click on any story claiming to have an answer on how to get their baby to sleep all night.
Also, the age of the babies was 6-16 months old, so these results are not applicable to babies younger than 6 months for sure. Many parents start sleep training at very young ages, which likely is more harmful for several reasons than it would be for an older infant or toddler.
Then there's the explanation of what the parents actually did (assuming they followed the instructions of the researchers). The headline calls it "cry-it-out", yet the actual interventions being studied were graduated extinction and bedtime fading, which are both extremely different from putting your child in a room, closing the door, and not getting them until morning. "Cry-it-out" means different things to different people. In this study, no child was ever left to cry for more than 35 minutes at a time. So they really weren't left to "cry-it-out" at all! Bedtime fading was a technique that actually made me laugh out loud, because it's what I've always done without even knowing I was "sleep training"! They just pushed back the bedtime until the baby was actually sleepy. Which begs the question, why were these parents trying to put a baby to bed who wasn't even tired? Maybe because society tells us our babies should be tired at a certain time or we're comparing our baby to someone else's.
Most obnoxious of the results of this study to me was the result of the babies left to cry for half an hour at a time ended up sleeping SO much better! Really? They went to sleep, on average, after several nights of crying for almost 15 minutes before the babies who were held and comforted by their parents. It just doesn't seem like much benefit in relation to the stress of listening to a baby cry. And a year later, babies were sleeping the same. So it's not as if parent have to do some type of sleep training or their children will always have issues with sleep, as they're often told.
What about the definition of "sleep problems"? These were just parents who self-reported that their child had a problem. Did they really, or were they normal children who had parents that had bad information or expectations? Were the parents overworked and stressed and blamed normal child waking as the "problem"? No doubt some children need some help calming down for bed, but I just wonder how many children in this study got better at sleeping longer just because the parents calmed down about it or because they got older.
The unsure definition of "sleep problem" is similar to the definition of "behavioral problem", which was really the main reason for the study. Previous studies showed and many psychologists suggest that leaving a child to cry for extended period could cause distrust and problems with attachment even into adulthood. In this study, there was just a question a year later asking if the parent felt the child had behavioral problems, and there was no difference between groups. So there was no expert determining if the child had an actual sleep problem, had any behavioral problems a year later, and we still don't know if these children will have more relationship/behavioral problems as they get older. These are things that aren't easy to determine anyway, much less as a self-report by the parents, who may not know what a "behavioral problem" is or isn't.
What CAN parents do to help their little ones go to sleep?
If you're looking for help in determining what is normal for infant sleep and what to do to help your baby or toddler sleep better, this list of studies is far more helpful and includes much bigger and well-designed studies. Never base your parenting decisions on one study or article! Go with your instincts that are well-informed by facts about how the human body and mind work.