4 Apr :A new study by Monash University has revealed that maternal smoking impairs the arousal ability of babies and increases the risk of sudden infant death syndrome (SIDS), the latest edition of the ‘SLEEP’ journal reported.
According to the researchers, although the exact cause is unknown, an impairment of the arousal process from sleep in response to a life-threatening situation could be involved.
"Our study suggests that maternal smoking can impair the arousal pathways of seemingly normal infants, which may explain their increased risk for SIDS," lead author Rosemary Horne said.
In their study, the researchers analysed 12 healthy, full-term infants born to mothers who smoked an average of 15 cigarettes per day. Their arousal responses during daytime sleep were monitored and compared with that of 13 healthy infants who were born to nonsmoking mothers.
Daytime polysomnography was performed on each child on three occasions — at 2 to 4 weeks, 2 to 3 months and 5 to 6 months of age. Arousals were induced without compromising the infants’ natural sleep cycles by delivering a pulsatile air- jet for 5 seconds via a cannula at the babies’ nostrils.
The results showed the progression from sub-cortical activation to cortical arousal was depressed in smoke-exposed infants, who had lower proportions of full cortical arousals from sleep and higher proportions of sub-cortical activations than infants born to non-smoking mothers.
The study also indicated there’s a dose-dependent relationship between cortical activation proportions and the levels of infant urinary cotinine, a nicotine metabolite.In fact, cortical arousals were lowest in babies with higher levels of smoke exposure