Sudden infant death syndrome (SIDS) is the sudden, unexplained death of an infant younger than 1 year old. The exact causes of SIDS are unknown, but researches found an association between maternal/prenatal and secondhand smoke  and SIDS. SIDS is the leading cause of death in infants between 1 month and 1 year old. Most SIDS cases happen in babies between 2-4 months old.

To learn more about smoking and SIDS visit Center for Disease Control and Prevention (CDC).