Sudden infant death syndrome (SIDS), substance misuse, and smoking in pregnancy

Kamal Ali, Na’eem Ahmed, Anne Greenough

Division of Asthma, Allergy, and Lung Biology, Medical Research Council and Asthma UK Center in Allergic Mechanisms of Asthma, King’s College Hospital, London, United Kingdom

Abstract: In the developed world, sudden infant death syndrome (SIDS) remains the leading cause of death in the post neonatal period. This review highlights the association between maternal substance misuse and SIDS, and discusses whether the increased risk is explained by abnormalities of respiratory control. Substance misuse during pregnancy is common, and although the incidence of smoking has declined in recent years among pregnant women, an increasing proportion of mothers of infants who have died of SIDS smoke. The risk of SIDS is increased in women who take opiates, but not cocaine or marijuana, although infants exposed to either of these drugs suffer morbidity, including reduced birth weight. Nicotine exposure increases the risk of SIDS, particularly if both parents smoke, and there is a dose-dependent effect. A variety of respiratory abnormalities have been described in the infants of substance abuse mothers, which may increase their risk of SIDS. These abnormalities include a reduced ability to recover from prolonged apnea and a blunted response to hypoxia and hypercarbia. These results are consistent with postmortem brainstem abnormalities reported among SIDS victims.

Keywords: sudden infant death syndrome, nicotine, opiates