In her new guide to raising children, Beyond the Sling, published this week by Touchstone, former Blossom star Mayim Bialik describes her family’s unconventional sleeping situation: Every night, she and her husband go to bed with their two little boys on a pair of futons laid side-by-side on the floor.
Bialik, who brandishes a Ph.D. in neuroscience, notes that the arrangement isn’t ideal. She and her husband never have sex in bed anymore, for one thing, and it looks to others “like we are staying in a youth hostel,” she writes. But Bialik loves that bed sharing allows her to nurse on demand and attend to her kids’ needs at all hours of the night. “Knowing that my babies were right next to me at night allowed me to rest knowing that I could tell if they were too hot, too cold, not breathing right—whatever,” Bialik explains in the book. La Leche League International, a nonprofit organization that promotes breast-feeding, recommends parent-infant bed sharing for these reasons, too.
But the American Academy of Pediatrics, the largest professional pediatric organization in the United States, disagrees. It argues that babies are more likely, not less likely, to stop breathing, overheat, or die when they sleep next to their parents. A 2012 meta-analysis of 11 case control studies, which the association cites in its most recent policy statement on the issue, reported that babies who share a bed with their parents are almost three times as likely to die from Sudden Infant Death Syndrome—an umbrella term for all unexpected, unexplained deaths occurring within one year of birth—as their crib-sleeping counterparts, increasing overall SIDS risk for an American infant from 0.047 to 0.136 percent.
So who is right? Are the estimated one-third to one-half of American parents who snooze next to their infants keeping them safe, or risking their lives?
You wouldn’t know the answer from reading Bialik’s book. She doesn’t address any scientific concerns about bed sharing, discuss any studies, or even refer to SIDS in her chapter on sleep. Her underlying reasons for bed sharing are anthropological: “Sleeping alone leaves you vulnerable and is rarely done by most animals in nature.” Bed sharing, she notes, only fell out of favor once people began distancing themselves from old-world ways. Before that, humans were doing it for tens of thousands of years, just like our evolutionary ancestors. The idea that parents should “return to the instinctual parenting of our ancestors” is the basis of attachment parenting, a controversial theory that Bialik endorses and uses throughout her book to advise parents on topics including potty training, discipline, and medical interventions.
Now the practice of bed sharing appears to be coming back into favor again—and a close look at the science suggests that the context in which parents do it, and the choices they make beforehand, matter a lot in terms of safety.
Mothers who smoke, for instance, should never sleep with their infants. The authors of the 2012 meta-analysis found that moms who bed shared and smoked had babies who were 6.27 times more likely to die of SIDS than were babies of crib-sleeping nonsmokers. But when nonsmoking mothers bed shared, their babies were no more likely to die than they would have been if left to sleep in a crib. But is smoking itself the only culprit here, or does the combination of cigarettes and shared beds exacerbate the problem? A 2009 study published in the British Medical Journal suggests that mixing the behaviors does have a particular, negative effect.
It’s not necessarily that these parents are lighting up in bed and setting their babies on fire, or choking them with secondhand smoke. Instead, some experts postulate that the pollutants and toxins these babies were exposed to during pregnancy predispose them to SIDS. Maternal smoking might interfere with fetal brain development in ways that ultimately prevent babies from being able to rouse themselves when a pillow or sheet covers their face or they get overheated.
Parents who get high or drink are also putting their babies at increased risk of SIDS if they sleep next to them instead of putting them in cribs. This is presumably because the parents are more likely to smother them by accident, and less likely to respond to cries or thrashing if this happens. Although the frequency of drug and alcohol use among bed-sharing parents is not known, drug-using parents may be more likely to bed share because they don't have the money for cribs, or because they just happen to pass out next to their babies. Parental drinking could also be a risk factor for SIDS even without bed sharing, of course: A 2010 study found that SIDS cases tend to spike around New Year's Eve. But bed sharing while drunk seems to be especially dangerous.
Where parents and babies sleep, what kind of bedding they use, and who else sleeps with them may also make a difference. One-sixth of babies who died from SIDS in the 2009 British Medical Journal study had been sleeping next to a parent on a couch, which experts consider particularly dangerous because space is tight and babies can more easily suffocate or wedge themselves against the sofa arms or back. In addition, babies who sleep on soft bedding and with pillows or comforters are more likely to die than babies sleeping on harder mattresses without pillows or covers. This could explain why infants in Japan, where hard futons are popular, have low rates of SIDS despite high rates of bed sharing. Finally, when parents sleep with their babies and other children all together, SIDS risk spikes by more than a factor of five, according to a 2003 study conducted in Chicago. Age is also an important factor: Babies at less than 12 weeks are much more likely to die of SIDS while bed sharing than are older babies.