The what, why, and how of infant sleeping positions. Rule number one in infant care: Put Baby to sleep on his back! Here’s why and what to watch for when you try it.
People often lament jokingly that babies don’t come with instruction manuals. And first-time parents sometimes feel truly surprised at being sent home from the birthplace with a one-, two-, or three-day-old and no experience whatsoever: “They’re letting us take him home by ourselves? Are they nuts?”
One instruction you will definitely be given at any hospital or birth center, however, is to place your infant on her back to sleep. They’ll even send you home with little doorknob signs saying “Back to Sleep” to remind you.
Now, you may sometimes wish your baby would get back to sleep, or you may be tempted to scratch out Sleep and change the sign to “Back to Wail and Cry.” But stick with it; back sleeping for newborns is more than a baby-care fad; research shows it’s safest.
Why Should Baby Sleep on His Back?
In 1974, Congress passed the Sudden Infant Death Syndrome Act in an effort to discover what was causing the devastating and seemingly inexplicable deaths of otherwise healthy infants while they slept. More than two infants for every thousand born were dying this way every year. Thanks to research by the National Institute of Child Health and Human Development (NICHHD) and others, a correlation was soon seen between sleeping on the stomach and increased rates of sudden infant death syndrome (also called SIDS, or “crib death” in the past).
By 1991, the research was convincing enough that the American Academy of Pediatrics (AAP) was recommending back sleeping. And in 1994 the NICHHD and the AAP pushed a full-on national public health education campaign called Back to Sleep. Since that time there has been a remarkable 50 percent decrease in the incidence of SIDS, according to the AAP. “Other countries with similar campaigns have had similar success,” notes pediatrician Karen Sadler, MD, yet the AAP and NICHHD report it is still the leading cause of death after the immediate postnatal period. “Ninety percent of infants who die of SIDS are under six months of age; most are between three and five months old,” Sadler adds. “Neither do we know why this is the most vulnerable age.”
For those still looking for a more definitive answer to why Baby should sleep on his back in order to prevent SIDS, there are a few likely explanations but no decisively certain one. We do know for sure that the statistical link between back sleeping and lower SIDS rates exists. Most of the explanations pertain to infant breathing. For example, when sleeping on her front, Baby is more likely to create a little pocket around her nose and mouth that traps the exhaled carbon dioxide, which is then re-breathed, reducing oxygen in her system to lethal lows. Similarly, heavy blankets or plush toys could cause this same CO2 poisoning, especially when Baby has her face against the fluffy stuff. Another explanation is that back sleeping helps keep airways more open.
Overheating may be a contributing factor. So skip the blankets and put Baby in an adorable sleep sac outfit or gown with a drawstring bottom and hand covers if you live in colder climes. Keep the room comfortable for a lightly clothed adult. Smoking in the household or by the mother before birth is also linked to sudden infant death syndrome. So for this and a thousand other reasons, quit smoking as soon as you think of conceiving.
One key point is that babies should sleep on their backs every time they sleep, whether for the night or just while napping, and all caregivers who take care of the child should know this. The rate of SIDS among back sleepers who were then put on their stomach to sleep is a scary 18 percent higher than the usual rate.
What Is SIDS?
According to the NICHHD, sudden infant death syndrome is technically defined as “the sudden death of an infant under one year of age, which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history.”
SIDS is a new parent’s worst fear. An apparently healthy baby with no obvious previous or present illness goes to sleep and never wakes up. As the NICHHD definition states, examination of the infant’s medical history, home, and even an autopsy do not reveal a cause of death in true SIDS cases.
Infants at increased risk for SIDS are those older than one month but younger than six months, those born prematurely, males, and twins or triplets. African-American babies are at higher risk than babies of European descent, and American Indian or Alaskan Native babies are considerably more so—up to two or three times the national average.
While breathing issues are the start of a SIDS death, recent research suggests that its deadliness comes in combination with a wiring problem in the baby’s brain. Certain infants may have a delay in maturation or poor development of a network of brain cells normally responsible for waking or alerting the child when a life-threatening situation (like lack of oxygen) is present. The brain areas involved develop in midgestation.
In 1990, there were 5,417 reported SIDS deaths in the US, according to the National Vital Statistics Reports, National Center for Health Statistics, and in 2006 there were 2,246 such deaths reported, which attests to the efforts to prevent it. (The infant mortality rate from all causes declined in that period as well, it should be noted, and preliminary results for 2020—the most recent figures available—show a further decline.)
The Back to Sleep recommendation is for healthy infants only. Those with upper airway anomalies, gastroesophageal reflux, or other problems may or may not benefit from sleeping on their backs. Parents should discuss these special situations with their child’s doctor.
Are There Any Downsides to Back-Sleeping?
The number-one problem with back sleeping is the possibility of developing a misshapen head, from lying on the same spot on a still somewhat soft skull all the time.
Back sleeping may cause flat spots on the back of the head, which you may hear called by its fancy name, positional plagiocephaly. This is a cosmetic concern that rarely requires surgical intervention. According to Dr. Sadler, “There are no neurological problems associated with positional plagiocephaly. Development is indeed normal, and in the vast majority of cases the asymmetry resolves as the infant spends more time upright, rolls over in bed on his/her own, and spends less time sleeping. It only becomes a cosmetic issue when the molding is severe, or when the child is approaching the age of two when the growth of the head is 75 percent to 80 percent complete.”
Most health insurance plans won’t cover treatment for cosmetic problems like an asymmetrical head if it is not causing a health problem, so parents should be alert to this possible side effect of back sleeping, and take preventive measures.
Changes in head shape can usually be prevented or treated by alternating the head position (facing left or right) during sleep from week to week or day to day. Changing the baby’s orientation to outside activity such as the door to the room often accomplishes this. Changing the placement of interesting things such as mobiles or mirrors beside the crib can also entice Baby to look the other way. Babies should also spend time on their stomachs when they are awake. In extreme cases where the asymmetry is noticeable and the baby resists measures to change head position, a pressure-distributing helmet can be used during sleep, but this has largely fallen out of favor.
Another problem that can plague parents is a baby who seems to refuse to sleep on his back. The AAP used to suggest side sleeping in such cases, which didn’t seem to reduce the SIDS risk as much as back sleeping but was at least a big improvement over tummy sleeping, but since 2005 the organization has not recommended side sleeping. Dr. Sadler observes that “many, many children have slept on their stomachs and done fine.” “However, any increased risk isn’t worth it when it comes to a child,” she says, “so I’d encourage you to keep Baby on his back—despite the wails—at least until he is well past six months old.”
One remedy for both of these problems is a lot of tummy time. Time spent on her belly, holding her head up, kicking her feet, reaching for objects around her, or playing with textural parts of a play mat give Baby’s head a break from pressure on the skull. They also provide mental stimulation and physical exertion, both of which should help her sleep better when her next naptime rolls around.
What Other Sleep Recommendations Do Experts Give?
The AAP policy recommends back sleeping first and foremost for babies. But its other recommendations for healthy sleep include these:
- A firm sleeping surface is safest (such as a firm mattress covered by a sheet). Fluffy mattress covers or sheepskins should be avoided for sleeping.
- Skip loose bedding and stuffed animals. Make sure any crib bumpers are thin, firm, and securely attached to the crib sides.
- Don’t smoke during pregnancy, and don’t allow smoking in the house where the newborn lives. Likewise avoid other smoky situations (such as a daycare provider’s) for the baby.
- Co-sleep safely. While there are many proponents of co-sleeping in Mom and Dad’s bed, the AAP’s recommendation is to let an infant sleep in the same room but not the same bed. A “sideca” arrangement or bassinet or crib in the mother’s room is what the AAP deems safest, with the baby in the adults’ bed only for nursing and comforting.
- Offer a pacifier at sleep time: It seems correlated with lower SIDS incidence. You might wait a few weeks to start this, so as not to add any confusion to breastfeeding habits. Offer the pacifier before laying the baby down. Don’t try to insert it after Baby is asleep, and if Baby refuses it don’t force it. The pacifier may help make Baby more arousable or hold the mouth in position to keep the airways open. Using it up to one year of age should not interfere with dental structure.
- Avoid overheating the room or overdressing the baby.
- Save your money and don’t buy devices that are promoted as SIDS prevention. None have been tested rigorously enough to stand up to the claim, according to the AAP.
- Likewise, don’t rely on audio, video, or movement monitors to prevent SIDS. There is no evidence that their use reduces the incidence of SIDS.
Watch for and take the measures noted above to prevent a misshapen head on your happy, healthy, back-sleeping baby.