Validation of algorithm to identify American Indian/Alaska Native pregnant women at risk from pandemic H1N1 influenza.

Pregnant women and American Indian and Alaska Native people are at elevated risk of severe disease and mortality from 2009 pandemic influenza A/H1N1. We validated an electronic health record-based algorithm used by Indian Health Service to identify pregnant women in near real-time surveillance of pandemic influenza A/H1N1. We randomly selected a stratified sample of 515 patients at 3 Indian Health Service-funded hospitals with varied characteristics.