RICHMOND, AUG. 12 -- The board of the A.H. Robins Co. voted today to approve a definitive merger agreement between Robins and the Rorer Group Inc.

A tentative agreement to merge was announced by the companies a month ago.

The definitive agreement approved by Robins' board is subject to approval by the U.S. Bankruptcy Court in Richmond, where Robins has been reorganizing its finances while under Chapter 11 of the federal bankruptcy law.

The company filed for protection from creditors because it was unable to pay billions of dollars sought by women who were injured by the Dalkon Shield, a defective contraceptive made by Robins.

Court approval of the merger will be sought in the near future, said Roscoe E. Puckett Jr., a Robins spokesman.

Murray Drabkin, counsel to the Dalkon Shield Claimants' Committee, said in recent court papers that "it is unlikely in the extreme that it will ever become effective."

Puckett said Robins and Rorer are working toward a mutually agreeable amended plan of reorganization that is to be filed in the court Aug. 21.

Robins had filed a reorganization plan in April, before the merger proposal was announced.

Even if the plan wins court approval after a hearing set for Nov. 5, it won't go into effect unless it wins confirmation by a vote of the creditors, most of whom are victims of the Dalkon Shield contraceptive.

Under the original plan, Robins proposed to satisfy claims against its ill-fated Dalkon Shield birth control device with a $1.75 billion trust fund to compensate victims of the IUD