Felicia Hance Stewart, a nationally known women’s health expert who contributed to the introduction of the emergency contraception drug known as Plan B, died of cancer April 13 at her home in San Carlos, Calif. She was 63.

Stewart served in the Clinton administration as the senior national official responsible for family planning and population issues. Most recently, she was co-director of the Center for Reproductive Health Research and Policy at the University of California at San Francisco.

She brought emergency contraception, also called the “morning-after pill,” to the attention of some key physicians and medical officials before the pills were widely available, said Sharon Camp, president and chief executive of the Alan Guttmacher Institute, which brought Plan B to the commercial market. Stewart was a practicing clinician and researcher and was co-author of “Contraceptive Technology” (1998), a standard reference work in the field of family planning.

Morning-after pills are higher doses of the hormones in regular birth control pills and have been sold by prescription since 1998 under the brand names Plan B and Preven. They are available without a prescription in several states; a FDA panel of experts has recommended that they be available over the counter nationwide, but the agency has not acted on the advice.

Donna Shalala, former secretary of health and human services in the Clinton administration and Stewart’s boss in the mid-1990s, called her “the perfect appointment because she was a grown-up and highly respected … an unusual combination of a first-class physician in an area just fraught with politics who never lost her head.

“She played a very important and very cautious role,” Ms. Shalala said. “She made sure we did not overstate [the benefits of] Plan B because she felt it should be very carefully used and women should understand all the risks.”

Failure to prevent unintended pregnancies leads to more abortions, Stewart argued in scientific papers and public statements. “I don’t think anybody knows how many pregnancies occur because of delayed refills, or just not get ting pills on time,” she once said. “But it is really a lot. Anyone who works in an abortion clinic can tell you that.”

Her work also dealt with improving communication between doctors and patients in the field of women’s health. “I think you can summarize the whole reason people don’t talk about sexually transmitted diseases with the word ‘shyness,'” she said in 1997. “Patients are shy about raising the issue, and clinicians are shy about asking the questions, so you get a vicious circle of ‘Don’t ask, don’t tell.”‘

A native Washingtonian, she and her family left the district when she was a child. She graduated from the University of California at Berkeley. She received a medical degree from Harvard University’s Medical School in 1969 and then worked in Boston and New York before returning to California.

Stewart worked in private practice in Sacramento, Calif., for 20 years while also a part-time staff doctor for Planned Parenthood. She became director of medical research at the Sutter Medical Foundation in Sacramento in 1993 and the next year was appointed deputy assistant secretary for population affairs at HHS.

In 1996, she became director of reproductive health programs at the Henry J. Kaiser Family Foundation in Menlo Park, Calif., before joining the Center for Reproductive Health Research and Policy in 1999. She worked there until 16 months ago.

She also was author of “Understanding Your Body: Everywoman’s Guide to a Lifetime of Health” (1987).