Estimating the number of births to hepatitis B virus-infected women in 22 states, 2006.

Background: Estimating the annual number of births to hepatitis B virus (HBV)-infected women is essential for monitoring efforts to prevent perinatal HBV transmission. We describe a method for estimating births to HBV-infected women in 22 states during 2006. Methods: The number of births to HBV-infected women was calculated by (1) multiplying the number of US/Canadian-born mothers stratified by US race/ethnicity-specific HBV prevalence estimates, and (2) adding the number of foreign-born mothers stratified by their region of birth and multiplied by region-specific HBV prevalence estimates. Results: Of 2,359,912 births, an estimated 16,608 (0.7%) were to HBV-infected women. Foreign-bom women, who represented 25.3% of all mothers, accounted for 80.6% of estimated HBV-infected mothers. Estimated foreign-born HBV-infected mothers were from Southeast Asia (31.2%), East Asia (21.2%), and Africa (13.8%). Non-Hispanic blacks represented 55.1% of US/Canadian-born HBV-infected mothers. Compared with a previous estimate, which considers foreign-born status only for Asian/Pacific Islander mothers, this method estimated an additional 3000 births to HBV-infected women. Conclusions: Incorporating maternal country of birth and region-specific HBV infection prevalence likely enhances estimation of births to HBV-infected women in the United States. According to our estimate, approximately 10,000 births to HBV-infected women were not identified by state and local health departments in 22 states.