Population-based registries are essential public health information systems that provide data to support improvements in patient care and clinical decision-making. There are significant gaps in the data around contraceptive safety and efficacy for women with complex medical conditions. As medical advances in the US allow women with complex medical conditions to live through their reproductive years, there is a critical need to build a robust registry that will provide prospective, population-based quality data on contraception, concomitant medications, and other important factors related to various disease states. Cystic fibrosis (CF) is an example of such a complex medical condition. It is a rare genetic disorder that results from impaired ion transport across epithelial cell membranes, and primarily affects the respiratory system. CF affects approximately 7,200 women of reproductive age in the US. The CF Foundation has developed a patient registry, which serves as a model for many disease registries. Nonetheless, it does not include specific information about contraceptive use. This proposal outlines the process we will undertake to establish a pilot contraceptive registry for women with CF, which will be used to describe contraceptive care measures proposed by the Office of Population Affairs/CDC as well as to address gaps identified by the most recent update to the US Medical Eligibility Criteria for Contraceptive Use. Our long-term goal is to build a registry to determine the safety and effectiveness of contraception used by women with CF and to advance evidence-based clinical guidelines for women with complex medical conditions.