Combined prenatal drinking, smoking associated with nearly 12-fold increase in SIDS risk
The risk for sudden infant death syndrome, or SIDS, was nearly 12 times higher in infants with mothers who both smoked cigarettes and drank alcohol beyond the first trimester of pregnancy, according to a study published in EClinicalMedicine.
“This study highlights the heightened risk of dual exposures to prenatal smoking and drinking as risk factors for SIDS, particularly beyond the first trimester,” Amy J. Elliott, PhD, chief clinical research officer at the Avera Health Center for Pediatric & Community Research in Sioux Falls, South Dakota, told Healio Primary Care. “These prenatal risk factors for SIDS can be addressed early in pregnancy and open the opportunity for discussion, support and intervention to help women have a healthy pregnancy and infant.”
The Safe Passage Study is the first large scale, prospective study investigating associations between SIDS and prenatal exposure to alcohol and tobacco, according to Elliott. The observational, multicenter study was conducted at five sites in the United States — including two Native American reservations — and two sites in South Africa. The study sites were selected to include regions with high prenatal alcohol use and SIDS cases, as well as populations where ethnic and socioeconomic factors linked to SIDS are understudied.
Women reported their smoking and drinking status during a recruitment interview, in up to three subsequent prenatal visits, and again in a follow-back interview a month after delivery. Women-infant dyads were assessed at delivery, 1 month and 1 year.
Information on 10,088 women with 11,892 pregnancies and 12,029 fetuses were included in the study. At 1-year, 124 infant deaths occurred, 28 of which were classified as SIDS.
Infants born to women who smoked and drank beyond the first trimester of pregnancy had a SIDS risk 11.79 times greater (98.3% CI, 2.59-53.70) than infants who were not exposed to either substance after the first trimester of pregnancy.
Compared with infants who were not exposed after the first trimester, the relative risk for SIDS was 3.95 times greater (98.3% CI, 0.44-35.83) in those with mothers who drank past the first trimester and 4.86 times greater (95% CI, 0.97-24.27) in those with mothers who smoked past the first trimester.
The risk for having a child die from SIDS was 8.09 per 1,000 pregnancies in women with dual exposure, 3.5 per 1,000 pregnancies in women who just smoked, 2.19 per 1,000 pregnancies in women who just drank, and 0.54 per 1,000 pregnancies in women who reported no exposure or quit during the first trimester.
“Efforts to reduce prenatal smoking and drinking first start with conversations on a very complex and difficult subject,” Elliot said. “While many women will respond positively to education alone to discontinue drinking and smoking, there are others who will need more structured interventions. Clinicians should start these conversations early in pregnancy and be aware of the services available in their region and strive to support women in their efforts to have a healthy pregnancy.” – by Erin Michael
Disclosures: Elliott reports receiving grants from the NIH during the study. Please see study for all other authors’ relevant financial disclosures.