Susan F. Wood, a women’s health expert who resigned in protest from the Food and Drug Administration in 2005, accusing the agency of knuckling under to politics by not approving over-the-counter sales of the morning-after pill known as Plan B, died on Jan. 17 at her home in London. She was 66.

The cause was glioblastoma multiforme, a brain cancer, said Richard Payne, her husband.

Dr. Wood was assistant commissioner for women’s health at the F.D.A. during the presidency of George W. Bush when Plan B, a form of emergency contraception, became a flashpoint in the abortion wars.

An F.D.A. advisory panel voted 28-0 in 2003 that the pill was safe for nonprescription use. But senior agency officials disregarded precedent and refused to approve over-the-counter sales.

Plan B contains high levels of progestin, a hormone found in ordinary birth control pills, and agency scientists considered it to be a contraceptive. But abortion opponents argued that its use was tantamount to ending pregnancies. They further warned that ready access would lead to promiscuous behavior by teenagers, though no data supported that claim.

Dr. Wood and others believed that having emergency contraception available without a prescription would mean fewer unwanted pregnancies and fewer abortions.

In August 2005, the F.D.A. commissioner, Lester M. Crawford, announced that the agency could not reach a decision on whether to authorize over-the-counter use of Plan B and did not expect to reach one soon.