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