Cot Death - Can Maternal Smoking Be The Culprit?

Every parent's nightmare, cot death or more scientifically, the Sudden Infant Death Syndrome (SIDS), may not be as non-preventable as once thought. A recent study in the April 1 issue of the journal SLEEP has carried a report saying that maternal smoking has replaced stomach sleeping as the greatest modifiable risk factor for SIDS. Prenatal smoking has been associated with an impaired infant arousal process.

Results show that 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 indicates that there is a dose-dependent relationship between cortical activation proportions and levels of infant urinary cotinine, a nicotine metabolite. Cortical arousals were lowest in babies with higher levels of smoke exposure.

Sudden Infant Death Syndrome - Overview
Sudden Infant Death Syndrome is death of a baby, under one year of age that occurs in sleep and cannot be explained.

According to senior investigator Rosemary Horne, PhD, scientific director of the Ritchie Centre for Baby Health Research at Monash University in Melbourne, Australia, decreased cortical arousals from sleep have been observed in victims of SIDS prior to death.

"Our study suggests that maternal smoking can impair the arousal pathways of seemingly normal infants, which may explain their increased risk for SIDS," said Horne.

According to the authors, SIDS is the third-leading cause of infant mortality in the U.S. Although the exact cause is unknown, research suggests that an impairment of the arousal process from sleep in response to a life-threatening situation is involved. Autopsies of SIDS victims have revealed brainstem abnormalities in key areas that are required for arousal and cardiorespiratory control.

Babies 'Cot' Dead - Why?
Dundee University researchers seem to know what makes certain babies prone to SIDS and serious health ailments.

The study involved 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 five seconds through a hand-held cannula at the infants' nostrils.

Prenatal Smoking is a 'Double-edged Sword'
Smoking during pregnancy is a 'double-edged sword' in respect of sudden infant death syndrome (SIDS) - as it not only does raise a mother's likelihood of having a preterm baby, but

The air pressure was increased incrementally until arousal criteria were met. Sub-cortical arousals were defined by body movements, heart rate increases and respiratory changes. Full cortical arousals involved a sub-cortical arousal that was accompanied by an abrupt change in electroencephalogram frequency.

According to the authors, 15 percent to 25 percent of pregnant women in Western countries smoke throughout pregnancy.

Every Parent's Nightmare: Study Explains "Cot Death Syndrome"
European scientists have shed new light on the causes of the devastating, inexplicable syndrome known as sudden infant cot death, according to a study published Thursday.

Source-Eurekalert
TAN/L