Pregnancy: maternal smoking induces a risk of sleep apnea in preterm infants

The preterm infants who were exposed to cigarette smoke in utero have an increased risk of respiratory problems such as sleep apnea, according to a study published in the journal "American Journal of Respiratory and Critical Care Medicine."

"Prenatal exposure to cigarette smoke is associated with an increased risk of sudden infant death," recalls Dr. Narong Simakajornboon and colleagues at Tulane University in New Orleans (USA). "But the effects of maternal smoking on sleep apnea occurs in premature infants were hitherto poorly understood," they add.

Therefore, the researchers used polysomnography to study the effects of maternal smoking on sleep and the occurrence of apnea in 16 preterm infants exposed to cigarette smoke, comparing them to 14 others who don ' have not been passive smoking during pregnancy (control group).

A significant increase in apneic index (number of apneas occurring over a period of time) has been observed in premature infants exposed to maternal smoking: 28.6 versus 13.2 per hour per hour in the control group, appearing only during the active phase of sleep.

Children born to smoking mothers also showed a decrease in arousal index (34.5 versus 46.3 per hour per hour in the control group).

Passive smoking during pregnancy has also been correlated with a specific reduction in the percentage of consecutive awakenings respiratory disorders (10.7% versus 29.4% in the control group).

"The increase in the number of apneas and reduced ability to awaken the children subjected to maternal smoking explain the increased risk of sudden infant death in such a case," the authors conclude.