Fact
Maternal smoking during pregnancy and exposure to secondhand smoke in infancy increases the risk of Sudden Infant Death Syndrome (SIDS).
Source 1:
"The Health Consequences of Smoking—50 Years of Progress. A Report of the Surgeon General." U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health. Smoking-Attributable Morbidity, Mortality, and Economic Costs. 2014. Report.
http://www.surgeongeneral.gov/library/reports/50-years-of-progress/sgr50-chap-12.pdf