Infants Who Normally Sleep on Their Backs at Increased Risk for SIDS if Placed on Their Stomachs

From the WebMD Archives

Nov. 29, 1999 (Baltimore) -- Babies who are normally placed on their backs to sleep are at a greatly increased risk of dying from sudden infant death syndrome (SIDS) if they are then placed on their stomachs, according to a study in the November issue of the Archives of Pediatrics and Adolescent Medicine.

"The striking observation was the 18-fold increased risk of SIDS for infants unaccustomed to prone sleeping," writes the study's author, Edwin Mitchell, DSc, of the department of pediatrics at the University of Auckland in New Zealand. Prone means lying face down.

The study included 485 infants who died of SIDS in New Zealand from 1987 to 1990 and 1,800 infants who did not die of SIDS. Many variables were examined including socioeconomic status, circumstances surrounding the pregnancy, the infant's sex, birth weight, length of pregnancy, and the breastfeeding and smoking practices of the mother.

"Parents were shown a number of drawings and asked the following questions concerning [infant] sleep position," writes Mitchell. "Which drawing best describes the way you usually put your baby down to sleep in the last two days, which best describes the position you usually found your baby after sleep in the last two days, and which best describes the way you put your baby down for the last time?" Parents whose infants had died were also asked what position the baby was found in when he/she died.

Infants usually placed on their backs or sides were at the lowest risk for SIDS. Infants placed face down were at a fourfold increased risk of SIDS. But those infants usually placed on their backs who were placed on their stomachs for the last sleep were 18-times more likely to die of SIDS than the first group.

The authors suggest that one reason the face down or prone position might result in SIDS is that infants have trouble breathing in that position but lack the neck and head strength and coordination to move.

The authors also suggest that infants who have fallen asleep in a prone position while playing not be left in a prone position. That statement is supported by Phipps Cohe, the national public affairs director for the SIDS Alliance. "We are well aware of this research on 'unaccustomed to prone' risk for infants. In working with Dr. Bradley Thach, MD, one of the study's authors, we became aware of the risk to infants when taking naps of being placed in the prone position by parents who otherwise never placed their babies prone. These parents mean well and simply don't want to wake the baby up by changing his or her position, but this study demonstrates that that is not a good idea."

According to Cohe, who commented on the study for WebMD, the biggest risk to infants here in the U.S. of being placed face down is by grandparents or child care providers who don't know that the position is potentially deadly. She says, "We need to become more vigilant to educate older people and child care providers about this issue. Our research shows that parents place babies nonprone almost 80% of the time, but we have a lot of work to do to get child care providers to that number."

Vital Information:

  • Infants placed on their stomachs, but who are accustomed to sleeping on their backs, have an 18-fold increase risk of dying from SIDS.
  • Infants who normally sleep on their stomachs have a fourfold increased risk of SIDS compared to those who sleep on their backs.
  • Parents should give instructions on sleeping position to grandparents and other child-care providers.