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.
It's important to note that most studies on bed sharing have looked only at the generic category of SIDS deaths, which includes all babies who suddenly and unexpectedly died of unknown causes. Many of those might have been suffocated or overheated—among the two most likely causes of bed-sharing deaths—but others could have died for unrelated reasons. (Five to 10 percent of SIDS cases occur without any apparent risk factors—the baby is found lying on his or her back without pillows or bedding, having simply stopped breathing.) But more specific data may soon be on the way. In 1996, the U.S. Centers for Disease Control and Prevention released a protocol for infant death scene investigation, with the goal of better understanding the factors and circumstances involved in unexpected infant deaths. Since then, bed-sharing-associated infant deaths specifically attributed to suffocation have quadrupled, and bed-sharing deaths more generally characterized as SIDS have correspondingly dropped. Some reports (including an article published in Slate in 2009) have highlighted growing infant suffocation rates as possible evidence that bed-sharing deaths are increasing, but the spike may simply be an artifact of the new labeling scheme.
So should parents bed share or not? From a public health perspective, the answer is a clear no—in general, babies are more likely to die when their parents sleep next to them. The American Academy of Pediatrics’ website for parents, healthychildren.org, recommends that babies “should sleep in the same room as the parents, but not in the same bed.” But if parents don’t smoke, drink, or use drugs, and if they sleep in a bed with a hard mattress and keep pillows, covers, and other kids away from their infants? Some studies do suggest some benefits. Mothers seem to awaken and nurse more frequently when they are sleeping with their babies rather than separately, and skin-to-skin contact between mother and baby has been shown to improve health outcomes, particularly in preterm infants. But it’s impossible to say for sure whether this practice is 100 percent safe. There are lots of potentially confounding variables at play, and scientists have never conducted a randomized, controlled study to find the answer. (Researchers who believe that bed sharing is intrinsically dangerous never would, for ethical reasons.)
Nevertheless, some doctors and parents find the American Academy of Pediatrics’ anti-bed-sharing recommendations unrealistic. Even if parents don’t intend to bed share, many inevitably do—particularly exhausted moms who bring their babies into their beds to nurse multiple times a night. (I accidentally fell asleep multiple times while nursing my 10-month-old boy, only to wake up in a panic and check that he was breathing. And I can’t help but wonder whether Bialik’s decision to bed share was also in part driven by convenience: Her eldest son woke up every couple of hours until he was 2 years old, she writes, and it’s far easier to tend to a crying baby when he’s next to you.) Other people bed share because they can’t afford cribs—bed sharing is more common among low-income families—and there are undoubtedly plenty of moms who sleep next to their kids because they are convinced that it helps them wake up when their infants need them, facilitates nursing, and helps to regulate their babies’ body temperatures.
Of course, any such benefits would be outweighed by the risks when bed sharing isn’t done safely. It’s surprising that Bialik—who prominently displays the Ph.D. next to her name on the book cover—fails to discuss these do’s and don’ts with her readers in her sleep chapter. A box separate from the main text notes that “you should co-sleep with your child only if you understand and adhere to the guidelines for safe co-sleeping,” and the Resources section at the back of the book mentions several books, articles, and products related to the practice, but considering that Bialik is encouraging her readers to sleep next to their babies, she should also spell out the risks and provide clear guidelines for safely doing so. Her take-home message seems to be, do what you feel as a parent, not what you’re told—even when the people giving the advice are scientists like herself.