Safe Sleep

by William Sears, M.d.

Safe Sleep

Dr. William Sears takes the fear out of putting Baby to bed

The call came at 3:00 AM: “Doctor, my baby’s dead!” Incredulous, I rushed out, only to find the devastated parents holding their lifeless baby. I will never forget their looks of horror and disbelief. It was the winter of 1972, my first year in pediatric practice and the first time I witnessed the grief and shock caused by sudden infant death syndrome (SIDS).

I had never felt so helpless. “Doctor, why did this happen?” the mother asked me. “My baby had her 3-month check up just a week ago, and she was so healthy. Five hours ago she was nursing contentedly; I went into her bedroom to check on her, and now she’s dead. What happened to her? Did we do something wrong?” The parents groped for answers, and I had none. All I could do was muster a faint “I don’t know.”

Now when expectant and new parents ask me if there’s anything they can do to avoid this awful fate, I can answer “Yes.” Over the past decade, new research has shed light on the possible causes of SIDS, and ways to reduce its risk. However, the horrifying mystery of the condition is still not completely solved, and nothing can guarantee absolute prevention. As a parent of eight, I am painfully aware that there is nothing more devastating than the death of a child  — and nothing more heart-piercing than the feeling that you could have done something to stop it. What’s important to remember is that SIDS is never your fault; parents who do everything “right” may still lose their child. But contrary to what you may hear, SIDS is still a rare occurrence: 99.9 percent of babies go to sleep each night and wake up just fine each morning. And there’s lots you can do to reduce your baby’s risk even further. Each strategy can lend much-needed peace of mind, allowing you to focus on what really matters  — enjoying your baby. Here are the four steps I recommend to parents to help keep their infants safe:

William Sears, M.D., is a contributing editor of BabyTalk.


Two of the highest risk factors for SIDS are prematurity and low birth weight. A three-pound baby, for example, is 10 times more likely to succumb to SIDS than a nine-pound baby. Why? Researchers speculate that these tiny infants have immature breathing-control centers, which may diminish their ability to rouse from a deep sleep should they stop breathing for some reason. Though these two situations aren’t always avoidable, you can fend them off by giving your pregnant body a healthy dose of TLC.


  • Get good prenatal care. Being monitored by a doctor or a midwife throughout your pregnancy may help you catch problems before they start. If you lack private health insurance, many states provide special prenatal care programs for little or no fee. Call your local or state health department for more information on available programs.


  • Eat well and often. Now is not the time to skimp on your three squares a day. Good nutrition lowers the risk of prematurity and therefore Baby’s SIDS risk later in life.


  • Keep your baby’s environment smoke-free and drug-free. Taking illegal drugs and smoking while pregnant increases the risk of SIDS in two ways: These dangerous habits can not only increase the chances of prematurity, but also harm the development of that all-important breathing-control center in Baby’s brain. Case in point: Babies born to mothers who abuse drugs are 5 to 20 times more likely to die of SIDS, in addition to having a higher risk of developmental problems.

    And it’s not much better for moms who smoke during pregnancy and their baby’s infancy. A large study conducted by the Centers for Disease Control found that babies exposed to smoke both before and after birth were three times as likely to die from SIDS. And the more cigarettes you smoke, the less oxygen Baby gets and the higher her risk. For example, if you smoke more than 20 cigarettes a day, Baby’s risk jumps five-fold. The bottom line: If you smoke, it’s crucial that you try to quit. To find a smoking cessation program near you, contact the American Lung Association at You can also contact the American Cancer Society at for pamphlets, brochures, and audiotapes on how to stop.


    The first major breakthrough in SIDS risk reduction came in the early 1990’s. Several studies from England, Australia, and New Zealand found that back-sleeping could save thousands of babies’ lives. There was finally something practical that professionals could agree upon and parents could do. In 1994, the U.S. Public Health Service organized a national “Back to Sleep” campaign  — an effort that has more than paid off: In the past few years, SIDS rates have dropped almost 40 percent in the United States.

    Though we still don’t fully know why back-sleeping works, we do have some theories:


  • Back-sleeping babies awaken easier. The ability to wake up in response to a stop-breathing episode is a healthy, protective mechanism. However, infants who sleep on their tummy tend to sleep more deeply than those who sleep on their back, making it more difficult to respond to breathing challenges.


  • Sleeping belly-up prevents overheating. Being a little too warm is unlikely to cause SIDS, but being hot can be a factor when it’s extreme (e.g., an overbundled baby with a fever in a toasty room). When Baby is sleeping on her back, her best heat releasers (her face, head, and abdomen) are exposed, making it easier to keep her body temperature in check. Still, it’s important to know the warning signs. If Baby exhibits any of the following, remove a layer or two: sweating, damp hair, heat rash, rapid breathing, restlessness, and sometimes fever. A few other rules:



    • Dress Baby for sleep as you would yourself (for babies under 2 months, add one layer).


    • Keep her head uncovered while she sleeps.


    • Maintain room temperature at about 68° F; try turning down central heating at night and using a warm-mist vaporizer where Baby sleeps.


    • Change Baby’s clothes appropriately if you bring her into bed with you. Your body’s an extra heat source.


    • Back-sleepers breathe more oxygen. When sleeping face-down, a baby may press her head into the mattress, which will form a pocket around her face. Instead of getting fresh air, she’ll be rebreathing her own exhalations, which have more carbon dioxide and less oxygen. Plus, some very young babies may not be strong enough to pull themselves up and turn their heads if they’re not getting enough air.

    Though back-sleeping is almost always best, there are certain circumstances in which belly-sleeping may be safer. This can be true for babies with structural abnormalities of the jawbones and airway, or those with gastroesophageal reflux, a condition where the stomach acid flows back into the esophagus, which could trigger a stop-breathing episode. Be sure to ask your doctor if there is any medical reason why your baby shouldn’t sleep on her back.

    And if you’re worried about your baby who loves to rock and roll onto his tummy, relax. Once babies start flipping, they’re almost out of danger. (SIDS is most common among babies 6 months and younger; it peaks between 2 and 4 months.) Just roll him back over when you can. Parents of side-sleepers can offer a little extra protection by pulling Baby’s bottom arm forward; it will act as a barrier.


    There’s no denying the health-promoting properties of human milk. And some studies have shown that breastfeeding may reduce some babies’ risk. One New Zealand study of more than 700 babies found that those who were breastfed were almost three times less likely to die of sudden infant death syndrome. So what’s the breast connection? Though researchers are not exactly sure, it appears to be a combination of several factors:

    First, there are hundreds of substances in human milk that aren’t in formula. And because breast milk is rich in immune-building factors, breastfed infants tend to get fewer infections, which lowers their risk. Not surprisingly, a baby’s immunity is lowest between 2 and 4 months of age, exactly when SIDS is most likely to occur. Why? Baby’s prenatal antibodies are wearing off faster than new ones are being produced. Breast milk can fill in the gap.

    Human milk also contains brain-building elements called “growth factors” that are not present in formula. Specifically, it’s rich in DHA, a fat that helps build myelin, the insulating sheath around nerves that help impulses travel faster. Though many formulas in Europe are fortified with this special fat, DHA is still under study here.

    Another plus: Breast milk is digested more quickly than formula, so nursing babies tend to wake up more frequently in response to hunger. Again, this easier arousability may lend them some extra protection. Plus, feeding more frequently means getting more opportunity to practice coordinating their swallowing and breathing. Tiny infants tend to have weak points in their their upper airways, making their breathing passages narrow, especially during sleep. Extra feeding time exercises the mouth and throat muscles that help keep those airways open.

    However, regardless of the benefits, the fact is some moms can’t nurse or do it as often as they’d like. If this is or was your experience, don’t stress too much. Millions and millions of formula-fed babies grow up to be healthy and strong, and chances are excellent that yours will too.


    The most controversial step in this SIDS risk-reduction program is sleeping close to your baby  — a nighttime parenting style I call “sleep sharing.” Last fall, the U.S. Consumer Products Safety Commission heated up the debate when they published a study reporting that 515 children under age 2 had died between 1990 and 1997 while sleeping in adult beds. More than 120 died when a parent or other sibling rolled on top of them, and nearly 400 were suffocated by bedding or bed structures. And based on this and other research, some organizations now strongly recommend against sleep sharing.

    I see this study from two perspectives: It’s helpful in that it reminds parents who do choose to sleep share that they must take precautions (see “Creating a Safe Sleep Environment”). But I also feel that it’s unnecessarily frightening. Mothers and babies have been sleeping together safely for thousands of years. Furthermore, the study had some fairly serious flaws. One of the biggest was that it didn’t compare the number of deaths in adult beds to the number of babies who died in cribs  — a number that is substantially higher. Without that crucial piece of information, parents are left with a scary scenario.

    Despite this study’s findings, it is still my opinion that sleep sharing can be beneficial for babies in families who choose to practice it safely. Here’s why:


  • Mom acts as a breathing pacemaker. Between 1 and 6 months of age, babies mature rapidly  — but not all of their skills develop at the same time. For instance, as each month passes, most babies begin to sleep longer and deeper, eventually snoozing all night long. That’s the good news. However, some babies’ built-in alarm systems may not yet be fully up to speed. Should they stop breathing, their brains might not get the message that they need to wake up and take a deep breath. That’s where I believe Mom can come in. Her warm body, rhythmically breathing next to Baby’s, reminds the child to keep breathing until she can handle the job on her own.


  • Mother’s presence heightens Baby’s arousability. When mother and baby sleep, they develop what I call “sleep harmony.” Both have simultaneous sleep stages, perhaps not perfectly attuned and not all night long, but close enough that they are mutually aware of each other’s presence without disturbing each other’s sleep. Because of this mutual sensitivity, the presence of the mother raises Baby’s arousability, and vice versa. In fact, studies have shown that infants who both nurse and share a bed sleep in shorter bouts and wake more than weaned infants, increasing that all-important ability to ascend out of deep sleep. Many moms also feel hypersensitive to their babies’ needs. I can’t count the number of times a mother has said to me: “I automatically wake up just before my baby starts to stir, and I nurse her back to sleep. Usually neither of us fully awakens, and we both quickly drift off.”

    I believe so strongly in the ability of breastfeeding and sleep sharing to decrease the risk of SIDS that I published my hypothesis in one of my early books, Nighttime Parenting. Needless to say, it was  — and still is  — an unpopular theory. So I decided to do my own experiment.

    In 1992, a new baby, Lauren, entered the Sears’s bedroom laboratory. The availability of new computer-assisted microtechnology gave us the opportunity to study the effects of sleep sharing on our baby’s breathing in a home environment. We set up equipment in our bedroom to study 8-week-old Lauren’s breathing while she slept in two different arrangements: One night, Lauren and my wife, Martha, slept together, as they were used to doing. The next night, the two slept separately. Lauren was wired to a computer that recorded her heart rate, her breathing movements, the airflow from her nose, and her blood oxygen. The instrumentation was painless and didn’t appear to disturb her sleep. The equipment was designed to detect only Lauren’s physiological changes during sleep; it did not pick up Martha’s signals. A technician and I observed and recorded the information. The data was analyzed by a computer and interpreted by a pediatric pulmonologist (a lung specialist) who was “blind” to the situation. That is, he didn’t know whether the data he was analyzing came from the shared-sleeping or the solo-sleeping arrangement.

    Our study revealed that Lauren’s breathing and heart rate were more regular during shared sleep. The results were similar in a second infant, whose parents generously allowed us into their bedroom. We studied Lauren and the other infant again at 5 months. As expected, the physiological differences between shared and solo sleep were less pronounced at 5 months old than at 2 months. Why? The babies were simply bigger and more developed.

    Certainly this study would not stand up to scientific scrutiny, mainly because of the small sample. We intended for this to be a pilot study that would stimulate other researchers to pick up where we left off. Furthermore, it’s not intended to guilt parents into choosing shared sleep or to imply that mothers should watch their babies’ every sleeping hour or feel bad for not doing so. Your sleeping arrangement is a highly personal decision. You need to do what comes naturally, whether it’s sleeping together, separately, or somewhere in between.

    So where does all this leave us? We still may be searching for a cure for SIDS, but we’re clearly leaps and bounds closer than we were just ten years ago. Finally, there are practical things we can do to reduce the chances of SIDS  — and that should help us all sleep better at night.



    Creating a safe sleeping environment





    • Put him to sleep on his back in a crib with a firm mattress that fits tightly within the frame.


    • Dress him in a sleeper to keep him warm instead of using blankets or other bedding.


    • Use a tight-fitting mattress cover.


    • Keep his crib free of stuffed animals, pillows, quilts, and comforters.


    • Don’t put him to sleep on a waterbed, sofa, pillow, or other soft surface.





    • Place the baby next to Mom, instead of between Mom and Dad.


    • Sleep in a large bed with a firm mattress, king-size if possible.


    • Use tight-fitting sheets.


    • Place the bed tightly against the wall, or install a mesh bed rail on the side where Baby sleeps.


    • Avoid waterbeds, and bed frames with slatted foot- and headboards.


    • Keep him on his back or side.


    • Never sleep next to your baby if you have been drinking, using drugs, or smoking.


    • Don’t allow older siblings to sleep next to the baby.


    • Have no more than one child in the bed at a time.


    • Avoid placing Baby too near your pillow or putting covers on top of him (instead, put him in a warm sleeper).


    • Don’t fall asleep on a couch with the baby. He could get caught between the cushions or fall off the edge.





    • Try a co-sleeper, which is a crib-like infant bed that securely attaches to your own. The benefits: You and Baby get your own space, but you’re still just inches away.







    • SIDS Alliance; 800/221-7437 or


    • National SIDS Resource Center; 703/821-8955.


    • SIDS: A Parent’s Guide to Understanding and Preventing Sudden Infant Death Syndrome by William Sears, M.D.



    SIDS Facts

    What is SIDS?

    SIDS is the sudden death of an infant under 1 year old that remains unexplained after performance of a complete post-mortem investigation, including an autopsy, an examination of the scene of death, and a review of the case history.

    How often does SIDS occur?

    SIDS is the leading cause of death in infants between 1 month and 1 year of age. In the United States, it occurs in approximately 1 in 1,000 babies. About 3,000 children die from SIDS each year.

    When is SIDS most likely to occur?

    Ninety percent of SIDS cases occur by 6 months of age, with most occurring between 2 and 4 months of age. SIDS occurs during an infant’s sleep, most frequently between 10 PM and 10 AM It’s more common in winter, and for unknown reasons, baby boys have a slightly higher risk.