Mothers who smoke during pregnancy increase their babies' risk for Sudden Infant Death Syndrome (SIDS), according to a study released Friday.
Smoking during pregnancy is linked to prematurity. The study, published in the American Journal of Respiratory and Critical Care Medicine, is the first to examine the effect of low oxygen and cigarette smoke on infants' heart rate and breathing.
Researchers studied 22 preterm infants in Calgary and found that exposure to cigarette smoke affected the babies' breathing, leaving them especially vulnerable to SIDS.
The infants were born between 28 and 32 weeks with no other complicating respiratory factors. The mothers of twelve of the infants had smoked more than five cigarettes a day during pregnancy. The mothers of the other ten infants did not smoke during pregnancy.
Results showed that those babies born to smoking moms did not recover as well, quickly or often to brief interruptions in breathing.
"This is a cause-and-effect relationship," Dr. Shabih Hasan, a neonatologist in the Department of Pediatrics at the Faculty of Medicine, University of Calgary told CTV.ca in a telephone interview. "The more you smoke, the higher the risk."
There have been previous studies about the link between smoking and SIDS, but this is the first to study preterm babies while still in the preemie stage.
"Smoking during pregnancy has two very serious effects with respect to SIDS," Hasan said. "Not only does it raise the likelihood of a mother having a preterm baby, who are already among the most vulnerable to SIDS, but it increases those infants' susceptibility to SIDS even further."
SIDS, also called cot or crib death, affects infants between the ages of one month and one year. Infants die unexpectedly and the cause of death is indeterminable. Hasan said SIDS affects 0.4 babies per 1,000 in industrialized countries. That number is higher in underdeveloped nations.
