Prevalence of birth defects among American-Indian births in California, 1983-2010

Approximately 6.3 million live births and fetal deaths occurred during the ascertainment period in the California Birth Defects Monitoring Program registry. American-Indian and non-Hispanic white women delivered 40,268 and 2,044,118 births, respectively. While much information has been published about non-Hispanic white infants, little is known regarding the risks of birth defects among infants born to American-Indian women.

This study used data from the California Birth Defects Monitoring Program to explore risks of selected birth defects in offspring of American-Indian relative to non-Hispanic white women in California. The study population included all live births and fetal deaths 20 weeks or greater from 1983 to 2010. Prevalence ratios and corresponding 95% confidence intervals (CI) were computed using Poisson regression for 51 groupings of birth defects.

Prevalence ratios were estimated for 51 groupings of birth defects. Of the 51, nine had statistically precise results ranging from 0.78 to 1.85. The eight groups with elevated risks for American-Indian births were reduction deformities of brain, anomalies of anterior segments, specified anomalies of ear, ostium secundum type atrial septal defect, specified anomalies of heart, anomalies of the aorta, anomalies of great veins, and cleft lip with cleft palate.

Our results suggest that American-Indian women having babies in California may be at higher risk for eight birth defect phenotypes compared with non-Hispanic whites. Further research is needed to determine whether these risks are observed among other populations of American-Indian women or when adjusted for potential covariates.