image for baby exercise article Cases of ]]>sudden infant death syndrome (SIDS)]]> in the United States have fallen more than 40% since the American Academy of Pediatrics (AAP) recommended in 1992 that infants be placed on their backs to sleep. In the hopes of eradicating SIDS, experts are now focusing on who isn't getting the message and why, as well as on other relevant sleep issues, such as bedding.

Nearly 2,500 infants die from SIDS each year. Once known as "crib death," because it often happens during sleep, SIDS remains the leading cause of infant death in the United States.

Defining SIDs

SIDS is the sudden and unexplained death of an infant under one year of age. SIDS deaths occur quickly, usually during sleep. The problem is most common among infants between two and four months of age, with the risk declining steadily as babies get older and stronger. Ninety percent of cases occur before 6 months of age. Boys are slightly more likely to fall victim to SIDS than girls. Low birth-weight and prematurely born babies are also at increased risk.

Two years after its 1992 recommendation, the AAP created the slogan "Back to Sleep," which has been adopted and disseminated by doctors, clinics, hospitals, the media, and even diaper manufacturers. The exact causes of SIDS still elude researchers, but studies have shown that back sleeping rather than stomach sleeping is the best way to prevent SIDS.

Family Members and Daycare Providers May Be Misinformed

Two recent studies, however, have revealed problems in implementing the AAP's message.

A survey released by the Consumer Product Safety Commission in July 2000 found that many grandparents in African-American families suggest to parents that they put the babies to sleep on their stomachs. Babies in African-American families are twice as likely to sleep on their stomachs as other babies.

In addition, a study released in the August 2000 issue of the medical journal Pediatrics found that more than 20% of SIDS cases occurred in daycare settings. The study of about 2,000 SIDS cases from across the country involved infants from mostly white, higher-income, educated households who were in daycare. Most of the daytime caregivers had children of school-age or older themselves, and often weren't aware of the "back to sleep" recommendations.

"Parents can't assume that just because a daycare provider has years and years of experience, he or she knows to put their child on her back," says Rachel Moon, MD, pediatric medical director at Children's National Medical Center in Washington, who led the study. "Just as you would talk to your child care provider about what you want your baby to eat and how you want your baby diapered, you should also talk about sleep position."

"Some of the confusion…is that the public perceives that we pediatricians can't make up our minds. And these caregivers and grandparents raised their children successfully when belly-sleeping was the norm," Moon says. "But the statistics are very, very strong. Whenever the baby is sleeping, she should be on her back."

Naps Are No Exception

Some parents and daycare providers believe that naps—as opposed to overnight sleeping—can be safely taken prone. But Moon strongly reiterated that only in rare cases should babies ever sleep on their stomachs. In fact, Moon said, a baby who is used to sleeping on her back at night may be at even greater risk for SIDS if she naps on her stomach. That's because children who sleep on their backs develop upper body strength less quickly than do babies who sleep on their stomachs. Because stomach sleeping causes a "trapping" of carbon dioxide and SIDS experts believe that rebreathing carbon dioxide is a factor in SIDS, it may be that these less developed babies can't move away from the trapped air they create when they sleep on their tummies.

"Parents should defer to pediatricians, and caregivers should require a note from a doctor when parents say their babies can sleep on their stomachs," Moon says. "Babies die from SIDS during the day as often as they do at night."

Misconceptions About Back Sleeping

Developmental Delays

Some parents worry about the fact that back-sleepers don't develop upper-body strength in the same way as stomach-sleepers. Back sleeping can cause some temporary, but unimportant, developmental delays. For example, studies have shown that babies who sleep on their stomachs start rolling over, sitting, creeping, crawling, and pulling to stand earlier than back-sleepers do. But the studies show that back-sleepers reach these milestones within normal age ranges. Experts like T. Berry Brazelton, MD, have always stressed that babies reach these milestones at different rates anyway, and Brazelton has long noted that it's normal for some babies to never crawl at all.

To help babies develop upper-body strength, the AAP recommends having daytime "tummy time," always supervised and always when the baby is awake.

Flat Head

Parents may worry that a baby's head will become flat is she sleeps on her back, because her skull bones haven't fused. Doctors have observed that such flattening sometimes occurs. It can usually be prevented by giving babies plenty of “tummy time” when they are awake and supervised. Even when flattening ("posterior plagiocephaly") occurs, it rarely poses a serious problem and can be managed where necessary by wearing a special helmet, or by alternating side sleeping (see below) with back sleeping. Pediatricians are confident that the small risk of head flattening is far outweighed by the importance of preventing SIDS.

Although side sleeping was originally suggested by the AAP to be an acceptable alternative position for preventing SIDS, it is no longer recommended. Babies who sleep on their sides can roll onto their stomachs, and studies continue to show an increase risk for SIDS in side sleepers compared to back sleepers.

Parents can also help prevent head flattening by playing with the baby while she's on her stomach.


Another fear regarding back sleeping is that babies will choke when they spit up. Because babies automatically swallow or cough up such fluid, doctors have found no increase in choking or other problems in babies sleeping on their backs. Statistics show that babies are more likely to choke on spit-up or vomit when they're on their stomachs.

Beware of Bedding

The AAP offers these recommendations:

  • The safest place for your baby to sleep is in a crib, cradle, or bassinet.
  • Use a firm, conventional mattress in your baby's crib.
  • Do not put infants to sleep on waterbeds, sofas, soft mattresses, feather beds, pillows, quilts, comforters, or sheepskins.
  • Do not use soft materials like pillows, sheepskins, stuffed toys, or loose bedding (like quilts or blankets) because they can obstruct the baby's airways, even if he sleeps on his back. Sometimes high-end blankets, like baby down comforters, are the most dangerous. If you get one as a gift, hang it on the nursery wall. (The SIDS Alliance recommends using sleeper suits rather than blankets.)
  • Do not cover your baby’s head with anything. If blankets are used, your baby’s feet should be at the bottom of the crib and the blanket tucked around the mattress to prevent movement into a position in which his head could become covered by the blanket.
  • Avoid overheating your baby. Use light clothing for sleep.
  • Do not use items like special mattresses or other devices that purport to reduce the risk of rebreathing. The products haven't been adequately tested, and some independent studies have shown that some of these items increase risk.
  • The SIDS alliance also recommends against putting babies to sleep in adult beds.

What Can I Do to Help Lower the Risk of SIDS?

  • Place your baby on his or her back to sleep, at nighttime and naptime.
  • Remove all fluffy and loose bedding from the sleep area.
  • Make sure your baby’s face and head stay uncovered during sleep.
  • Do not let your baby overheat during sleep.
  • Babies should never be put to sleep unattended on adult furniture, such as sofas or beds, because the baby can become trapped in crevices or corners or under bed sheets and suffocate.
  • Do not ]]>smoke]]> around your baby or let anyone smoke in your house. Households with smokers have higher rates of SIDS.
  • There is debate about the safety of parents sharing a bed with babies. Under certain conditions (eg, parents who smoke or use ]]>alcohol]]> or ]]>drugs]]> ), sharing a bed may increase the risk of SIDS.
  • Use a firm mattress in your baby's crib. Avoid soft bedding, toys, and blankets.
  • Keep the baby's room and the house at a normal, comfortable temperature. Similarly, don't overdress your baby. There's strong evidence that overly warm rooms raise the risk of SIDS.
  • Allow use of a pacifier during sleep.

And remember that once babies start rolling over onto their stomachs on their own, their risk for SIDS decreases dramatically; as long as you start the baby out on her back, there's no need to continually stand guard at the crib.