The US Food and Drug Administration, or FDA, published the “Guideline for the Study and Evaluation of Gender Differences in the Clinical Evaluation of Drugs,” henceforth “Study of Gender Differences,” in July 1993. The document defined acceptable practices for investigators studying new drugs. Prior to 1993, investigators excluded most women from clinical trials because in 1977, the FDA recommended that anyone who could possibly become pregnant be excluded from early phase drug research to minimize risk to a potential fetus. In 1997, the FDA reversed that guidance, advising investigators to include women in early phase drug research, a decision that reflected changing views about a woman’s ability to decide whether to participate in drug trials and furthering research on the effects of drugs on women.

In 1993, the NIH published the Revitalization Act that established guidelines for minorities’ and women’s participation in clinical research. Before the 1990s, investigators largely excluded women from their research based on the 1979 guidance from the US Food and Drug Administration, or FDA. The FDA urged investigators to exclude any woman who was or could become, pregnant to protect the woman and any developing fetuses from harm. Between 1979 and 1993, several other US governmental agencies urged investigators to increase the number of women in their clinical research to improve the state of women’s healthcare. After Congress passed the National Institutes of Health Revitalization Act, hereafter Revitalization Act of 1993, investigators who used NIH funds for clinical research were required to include both women and minorities in their clinical research. The Revitalization Act established the Office of Research on Women’s Health headquartered in Washington, DC and required investigators to include women in their clinical research, thus improving the quality of women’s health research.