New Animal Study Confirms That Smoking during Pregnancy is Major Risk Factor for SIDS

A recently conducted research has provided evidence that smoking during pregnancy can be directly associated with the baby’s risk for SIDS, or Sudden Infant Death Syndrome. Although a link between prenatal exposure to cigarette poisons from the smoking mother and SIDS was suspected long ago, the new trial confirms that it can be a key factor in sudden death of the infant. Other causes include irregularities in the heart beat, disruptions of breathing, faults of the nervous system and overheating.

A leading author of the study, Dr. Shabih Hasan of the University of Calgary, Canada, has commented on the results of the research that smoking during pregnancy is now considered the primary risk factor for Sudden Infant Death Syndrome. Chronic exposure of the fetus to cigarette fumes directly contributes to breathing abnormalities caused by oxygen and thermal stress and hypoxia. These conclusions were reported at a recent issue of the American Journal of Respiratory and Critical Care Medicine.

To find out how a prenatal contact with tobacco smoke affects the fetus, the scientists divided pregnant laboratory rats into two groups – the first was exposed to tobacco fumes that would correspond to smoking one pack of cigarettes a day in humans; while the second, control group of pregnant rats, breathed an unpolluted air. The researchers’ approach was to investigate a negative effect on embryonic development of pups of all toxins found in cigarette smoke, not just nicotine. Since tobacco smoke is known to contain almost 5,000 various poisons, it is still not clear whether it is nicotine, or other harmful substances of tobacco fumes, which disrupt a normal development and postnatal growth of both the pups and human infants.

In the group of “smoking” rats, pups were born with a noticeably reduced weight. When a-week-old pups of both groups were randomly exposed to either hyperthermic or thermoneutral respiratory stress caused by oxygen depletion, their response to the test differed. Thirty six percent of smoke-exposed rats exhibited symptoms of significant respiratory reactions, including gasping for air, while, in the control group, only 13 percent of the animals showed similar behaviour. In addition, cigarette-poisoned pups showed pronounced symptoms of respiratory depression after the end of the test, while the control group quickly returned to their normal breathing patterns.

These results clearly indicate that prenatal exposure to tobacco fumes weakens the respiratory system of the newborns, which significantly elevates their proneness to developing breathing difficulties that can lead to SIDS. These scientific observations should further support the governmental efforts to encourage pregnant women to stop smoking in order to preserve the health and life of their babies.

John Burke