The centuries-old practice of swaddling may help young infants sleep more soundly, and could potentially protect against Sudden infant death syndrome (SIDS), according to researchers in France and Belgium.

Swaddling is an ancient practice that involves wrapping infants in soft materials to limit their movements and keep them calm during sleep. It is still used in Eastern Europe, the Middle East, Asia and elsewhere.

Swaddling keeps babies on their backs during sleep, which is what experts recommend for reducing the risk of SIDS.

In addition, it’s thought that swaddling can make for more restful sleep - and less nighttime crying - by restricting small infants’ movements.

When babies move less during sleep, fewer stimulating “messages” may reach the brain, Dr. Patricia Franco of Hopital Debrousse in Lyon, France, told Reuters Health.

She and her colleagues tested this idea by monitoring 16 infants between the ages of 6 and 16 weeks during sleep. Sensors placed on the babies’ skin recorded brain activity, heart rate and other physiological activities as they slept - first on their backs with no swaddling, then with swaddling.

With swaddling, Franco’s team found, the infants were less likely to awaken “spontaneously” and had longer periods of deep sleep.

On the other hand, they showed greater brain activity in response to low-volume “white noise” when they were swaddled. That finding, according to the researchers, indicates that a swaddled baby may be more likely to rouse from sleep when there are disturbances in their environment.

Past research, Franco and her colleagues note, has suggested that SIDS may stem, in part, from a failure of some infants to wake up during potentially dangerous situations - such as when they are overheated, or not getting enough oxygen because they are face-down.

Although all of the babies in the study woke up in response to noise, swaddled or not, they awoke more quickly when they were swaddled.

The reason is not fully clear, but Franco said that stronger heart rate increases in response to the noise could be involved; when swaddled, the infants generally had greater variability in their heart rates as they slept.

However, Franco said, it is too soon to recommend swaddling as a way to help young infants sleep more soundly or to reduce SIDS risk.

There are potential complications from the practice - particularly if babies are wrapped so that there is too much pressure on the chest or hips. Compression of the chest could obstruct normal breathing, while keeping an infant’s hips and legs overly restricted could impede proper development of the hip joints, Franco noted.

Another concern would be overheating, which along with stomach-sleeping is considered a SIDS risk factor.

“We want to be very careful before recommending this infant care technique,” Franco said.

SOURCE: Pediatrics, May 2005.