Updated Fri. Dec. 8 2006 11:29 AM ET
CTV.ca News Staff
A new British study is warning parents not to let their babies sleep in car seats because there is a risk they could stop breathing.
Researchers of the study in the British Medical Journal looked at more than 40 infants in New Zealand who were referred to a hospital service that studies newborns at high-risk for sudden infant death syndrome (SIDS).
Of those infants, nine suffered some sort of life-threatening event between July 1999 and December 2000 after being left in car seats.
According to the study, four of the babies were described as "limp and unresponsive" when they were found.
All of the babies, aged three days to six months, were described as "blue" or "not breathing."
When the researchers reconstructed the scene using the infants' own car seats, they determined that all nine of the babies had been sitting their heads with flexed forward.
"When they then went back and tried to reconstruct the situation, they found that none of these babies had any kind of abnormalities, their jaws were fine, their airways were fine. It was the positioning within the seat," Dr. Lou Francescutti told CTV's Canada AM from Edmonton on Friday morning.
They found the babies' heads tended to flop forwards, pressing the jaw into the chest. This position blocked the airways, making breathing a challenge.
"All but one case occurred when the infants had been left in the car seats indoors, allowing them to fall asleep unrestrained in an upright position," said a report by the researchers, led by Dr. Alistair J. Gunn, an associate professor of physiology and pediatrics at the University of Auckland.
Because "the infants (in the study) were very young (and their) head control is not well developed," the study authors suggest that this position is a potentially life-threatening one.
Francescutti, an expert in the field of injury control, explains that infants have not yet developed the head control or the muscles to reposition themselves when they have trouble breathing.
All of the infants survived but the parents were warned about leaving their babies in car seats for prolonged periods of time.
Parents should not be tempted to leave their sleeping babies in the car seat once they take them out of the car seat, the study warns.
Allowing babies to fall asleep when they are restrained in a relatively upright position could be fatal, the authors said.
"It's tempting to leave them there because they're sleeping. You're probably better off waking them up and repositioning them either in a crib or some other safe area," Francescutti said.
But the authors say other factors could also have played a contributing role. Half of the mothers in the study were smokers and smoke exposure is known to increase the risk of SIDS.
The authors of the study say that infant car seats could be modified to prevent baby's heads from flopping forward.
"What they're saying is that car seats should actually be redesigned so that they have a little bit of hole in the back so the baby's head can fall backwards and open up their airways," Francescutti said.