Grey literature (read a helpful definition here) is not published in traditional commercial venues nor included in major databases. It can take the form of research reports, theses and dissertations, newsletters, bulletins, pamphlets, blog entries, and more.
Grey Literature Report - From the New York Academy of Medicine. This website and database stopped being updated as of January 2017. The resources are still accessible and searchable, however. This site also has links to other medica grey literature sources.
Research Guide to Grey Literature - History of Medicine - NYU Libraries
Criteria to keep in mind when choosing and using soures:
Accuracy - Does the author cite her/his sources and are they legitimate?
Authority - Who wrote the source? Are they credible?
Objectivity - Does the author have a bias, political or commercial or persuasive?
Currency - Is this information new or based on outdated sources? Can you tell how current it is?
Massachusetts Department of Public Health
National Center for Health Statistics
Office of Minority Health (US Dept of H&HS)
WHO, Dept of Gender, Women and Health
Black Women's Health Imperative
Boston Women's Health Book Collective aka Our Bodies Ourselves
Center for Reproductive Rights
Feminist Women’s Health Center
Lesbian Health & Research Center
National Indian Women's Health Resource Center
National Latina Institute for Reproductive Health
National Library of Medicine: Health Services Research & Public Health Information Programs
National Women’s Health Network
Native American Women's Health Education Resource Center