Combined Prenatal Smoking and Drinking Greatly Increases SIDS Risk

Children born to mothers who both drank and smoked beyond the first trimester of pregnancy have a 12-fold increased risk for sudden infant death syndrome (SIDS) compared to those unexposed or only exposed in the first trimester of pregnancy, according to a new NIH-supported study.

SIDS is the sudden, unexplained, death of an infant under 1 year of age. Many studies have shown that the risk of SIDS is increased by maternal smoking during pregnancy. Some studies have also found that prenatal alcohol exposure, particularly from heavy drinking during pregnancy, can increase SIDS risk. Now, the NIH-funded Safe Passage Study provides a look at how SIDS risk is influenced by the timing and amount of prenatal exposure to tobacco and alcohol. A report of the study appears in EclinicalMedicine, an online journal published by The Lancet.

“Ours is the first large-scale prospective study to closely investigate the association between prenatal alcohol and tobacco exposure and the risk of SIDS,” said first author Dr. Amy Elliott of the Avera Health Center for Pediatric & Community Research in Sioux Falls, S. Dak. “Our findings suggest that combined exposures to alcohol and tobacco have a synergistic effect on SIDS risk, given that dual exposure was associated with substantially higher risk than either exposure alone.”