Susan Wood, assistant FDA commissioner for women's health and director of the Office of Women's Health, announced her resignation in an e-mail to agency colleagues. She wrote that she was quitting her position after five years because of unwarranted interference in decision-making.
Last week the FDA postponed its ruling on non-prescription sales of the "morning-after" pill, or Plan B. The agency said adults could use the pill safely without a doctor's guidance, but that young teenagers still required a prescription.
Commissioner Lester Crawford said the agency had yet to determine whether it could allow the pill to be sold over-the-counter to most women and prescription-only for girls under 17.
"I can no longer serve as staff when scientific and clinical evidence, fully evaluated and recommended for approval by the professional staff here, has been overruled," Wood wrote in her resignation e-mail.
"The recent decision announced by the commissioner about emergency contraception, which continues to limit women's access to a product that would reduce unintended pregnancies and reduce abortions, is contrary to my core commitment to improving and advancing women's health."
FDA scientists say the pills are safe, and in December 2003 the agency's scientific advisors resoundingly supported over-the-counter sales for all ages. More than 2.4 million Americans in addition to millions of women abroad use the pill with few side effects, according to the Associated Press.
Contraception advocates say easier access to the pill could halve the nation's 3 million annual unintended pregnancies.
Plan B opponents, however, have intensely lobbied the Bush administration, saying over-the-counter sales would encourage teen sex and that the pill is equivalent to abortion.
The drug works by blocking ovulation or fertilization, or by disrupting the implantation of a fertilized egg into the uterus, which is the medical definition of pregnancy.
It has no effect on women who are already pregnant.