Linkage of Pregnancy Risk Assessment Monitoring System and Alaska Birth Defects Registry to Describe Alcohol- and Tobacco-Related Birth Defects in Alaska

BACKGROUND: The CDC’s Pregnancy Risk Assessment Monitoring System (PRAMS) surveys pregnant mothers on several environmental and behavioral factors but does not capture birth outcomes. Meanwhile, the Alaska Birth Defects Registry (ABDR) captures reported birth defects from ICD codes but not maternal behaviors prior to, during, and shortly after pregnancy. By linking the two data systems, a thorough description and investigation of tobacco- and alcohol-related birth defects in Alaska is possible.

METHODS: PRAMS survey data from 2009-2011 (n=3,549, representing 33,417 births) were linked to ABDR data by birth certificate number. The prevalence of birth defects with known tobacco- and alcohol-related etiologies, such as cleft lip and palate, neural tube defects, and cardiovascular defects, will be described among PRAMS participants and within the Alaskan population. The relative risk of these birth defects for mothers who smoked tobacco and drank alcohol before, during, and after pregnancy will be estimated. PRAMS oversamples on Alaska Native and low birth weight babies—both subpopulations that have documented elevated rates of birth defects. This oversampling improves the overall power and probability of outcome detection in the population.

RESULTS: This study is in progress and results are preliminary. Weighted estimates based on the PRAMS survey showed that about 33.0% (95% CI: 31.0-34.9%) of Alaskan women smoked and 59.6% (57.5-61.6%) drank alcohol in the 3 months before pregnancy, 15.3% (13.9-16.8%) smoked and 6.4% (5.5-7.6%) drank alcohol in the last 3 months of pregnancy, and 21.5% (19.9-23.3%) smoked at the time of survey. Weighted estimates for cleft lip and palate showed that 47 (95% CI: 14-108) Alaskan infants per 100,000 had cleft lip, 267 (58-476) per 100,000 had cleft palate, and 3 (0-7) per 100,000 had both cleft lip and cleft palate. Further analyses will refine these estimates and estimate the prevalence of other conditions, including neural tube defects and cardiovascular conditions, and the attributable risk of these conditions for mothers who smoked tobacco and/or drank alcohol prior to, during, and shortly after pregnancy.

CONCLUSIONS: While associations between specific congenital conditions and maternal tobacco and alcohol use have been established, a thorough characterization of the burden of these conditions in Alaska attributable to drinking and smoking using these data systems has not been previously conducted. This effort will inform education and policy efforts to reduce these conditions in the state.