The new study - published in Pediatrics, the journal of the American Academy of Pediatrics (AAP) - assessed sleep-related infant deaths from 24 states during the period of 2004-2012, using the case reporting system of the National Center for the Review and Prevention of Child Deaths.
A new study suggests that bed-sharing is the single greatest risk factor for sleep-related deaths in younger infants.
According to the Centers for Disease Control and Prevention (CDC), the three most frequently reported causes of Sudden Unexpected Infant Deaths are: Sudden Infant Death Syndrome (SIDS), cause unknown and accidental suffocation and strangulation in bed.
The AAP state that SIDS is most common among infants that are 1-4 months old but that babies can die from SIDS until they turn 1 year old.
Because risk factors for sleep-related infant deaths may differ among different age groups, the researchers from this latest study divided cases into two groups: infants aged 0-3 months and those between the ages of 4 months and 1 year.
In total, the researchers analyzed 8,207 deaths and found that 69% of the infants were bed-sharing when they died.
In detail, the younger infants were more likely bed-sharing or sleeping on an adult bed or near a person, compared with the older infants - 73.8% versus 58.9%, respectively. Meanwhile, the older infants were more likely to be found prone with objects - such as blankets or stuffed animals - at the time of their deaths.
The researchers say their results show that sleep-related infant death risk factors differ for younger versus older infants and that parents should "be warned about the dangers of these specific risk factors appropriate to their infant's age."
'Babies should sleep in cribs near parents'
To minimize risks, the AAP say parents should follow their recommendations for a safe sleep environment (see fast facts box). Additionally, following safe sleep practices can also reduce risks.
For example, the organization recommends always placing babies on their backs while sleeping, as babies sleeping on their side are more likely to accidentally roll onto their stomach. Additionally, parents should avoid letting the baby get too hot by dressing the baby lightly for sleep and setting the room temperature at a comfortable level.
- Place the baby on a firm mattress covered by a fitted sheet that meets current safety standards.
- The crib should be placed in a smoke-free area.
- Do not place babies on adult beds, chairs, sofas, waterbeds, pillows or cushions to sleep.
- Do not put toys, soft bedding, fluffy blankets, comforters, pillows, stuffed animals or bumper pads in the crib.
- Better alternatives to blankets include sleep clothing, such as sleepers, sleep sacks and wearable blankets.
According to the AAP, the safest place for a baby to sleep is in the room where the parent or guardian sleeps but not in their bed. The crib or bassinet should also be free of toys, soft bedding, blankets and pillows.
There are certain steps mothers can take during and after pregnancy to reduce risk of SIDS, including not smoking or exposing themselves to others' smoke, and avoiding alcohol and drug use.
Additionally, around 1 in 5 SIDS deaths occur while an infant is being cared for by someone other than a parent, usually when babies who typically sleep on their backs at home are then placed on their tummies by another caregiver during sleep - known as "unaccustomed tummy sleeping."
As such, the AAP advise parents to speak with other caregivers about the importance of placing infants on their backs during sleep.
However, the organization notes that "tummy time" - playtime when infants are awake and placed on their tummies under supervision - is an important component of a baby's normal development. It strengthens neck muscles, allowing babies to eventually push up and crawl, and promotes development of motor skills.
In 2013, Medical News Today reported on a study in JAMA Pediatrics that suggested mothers who bed-share with infants breastfeed longer. Still, the AAP recommend that parents place the baby in a crib near their own bed to make it easier to breastfeed and bond.