RICHMOND, Va. (AP) _ A federal judge, citing a conflict of interest, has disqualified a law firm from representing a $2.5 billion trust fund set up to compensate women injured by the Dalkon Shield intrauterine device.

U.S. District Judge Albert V. Bryan of Alexandria, Va., ruled Wednesday that Cadwalader, Wickersham & Taft couldn't represent the trustees because it had advised claimants in the bankruptcy-law proceedings of A.H. Robins Co., a health-products firm that produced the Dalkon Shield.

A flood of personal injury lawsuits stemming from Dalkon Shield injuries had forced Robins to file for protection from its creditors under Chapter 11 of federal bankruptcy laws three years ago.

Bryan's ruling clears a major obstacle to the trust beginning to make payments to nearly 200,000 women with pending claims. American Home Products Corp., a New York health products company, has agreed to acquire Richmond- based Robins and provide most of the money for the $2.5 billion trust.

John J. Walsh, a partner at Cadwalder, said the company was considering an appeal. ''We respectfully disagree with the court's analysis,'' he told the New York Times.