Timing and Intensity of Maternal Smoking and Sudden Unexpected Infant Death

Maternal cigarette smoking is a known risk factor for sudden unexpected infant death (SUID), but studies to date have not included large populations with granular data on precise timing and intensity of smoking.

Using a large U.S. dataset of live births and infant deaths (>2 million births and over 19,000 SUIDs), researchers evaluated risk for SUID (including sudden infant death syndrome, ill-defined or unknown cause, and accidental suffocation or strangulation in bed) across categories of maternal smoking timing (prepregnancy and prenatal by trimester) and intensity (number of cigarettes smoked daily). They found the following:

• Any smoking during pregnancy was associated with more than double the risk for SUID.

• SUID risk was positively correl…