Why risk for sudden infant death syndrome is greater in babies of mothers who smoke

SIDS is the leading cause of death during the first year of an infant's life. The link between maternal smoking and SIDS is clear. Prenatal exposure to cigarette smoke puts infants at a 2- to 5-fold increased risk of SIDS and contributes to premature birth, another risk factor for SIDS. How exposure to the chemicals in cigarette smoke in utero increases the risk of SIDS has not been determined.

In the article, Hemant Sawnani, Erik Olsen, and Narong Simakajornboon, from Cincinnati Children's Hospital Medical Center (Ohio), summarize the evidence from both human and animal studies demonstrating that nicotine (in cigarette smoke) interferes with the development of the parts of the brain that control breathing. Nicotine exposure in utero leads to altered breathing patterns and ventilatory responses that compromise respiratory arousal and auto-resuscitation. Infants of mothers who smoked during pregnancy have more pauses in breathing (infant apnea) and have decreased ability to wake up from sleep in response to low oxygen. This sheds important light on why smoking during pregnancy increases risk for Sudden Infant Death Syndrome (SIDS, crib death).

"These findings highlight the importance of public health policies to prevent the development of tobacco dependence in adolescent girls and the importance of treatment of maternal tobacco dependence prior to pregnancy. Perhaps when young women are freed from the chains of tobacco addiction we can then truly say that 'you have come a long way… for your baby,'" says Harold Farber, MD, MSPH, Editor of Pediatric Allergy, Immunology, and Pulmonology, and Associate Professor of Pediatrics, Section of Pulmonology, Baylor College of Medicine, Houston, TX.