The Senate gave abortion opponents a dramatic victory Saturday, voting 50 to 44 to ban coverage of abortions in federal employee health plans except in cases of rape, incest or where the mother’s life is endangered.

The vote showed the renewed power of anti-abortion forces in the Republican-controlled Congress.

The House overwhelmingly approved a stricter abortion ban in July, and the differences between the two bills will have to be worked out in conference.

The unusual Saturday session, attended by 94 of the 100 senators, was dominated by nearly six hours of heated debate over abortion. It was the first showdown over the emotional issue since the Republicans gained control of the Senate in last November’s elections.

The Senate voted to reinstate abortion restrictions on federal insurance coverage that were in effect between 1984 and 1993, but dropped after Clinton took office. The restrictions affect the 9 million Americans who receive their health coverage under the Federal Employees Health Benefits Plan, which has been suggested as a possible model for revamping Medicaid and Medicare.

The abortion issue seesawed throughout the day as supporters of abortion rights first beat back a House-passed abortion ban that would permit federal insurance to cover only abortions necessary to save the mother’s life.

But the addition of language to allow abortions in the case of rape or incest broadened support for the bill, which won the votes of 40 Republicans and 10 Democrats.

Sen. Barbara A. Mikulski, D-Md., said, “It is inconceivable to me to deny women who work for the government the right to choose a health care plan that covers a full range of reproductive health services.”

The abortion debate engaged six of the Senate’s eight women members, who described it as an issue of constitutional rights and fairness and punctuated their comments with personal references. Mikulski pointedly thanked the “good men” of the Senate who voted to make abortions more widely available.

Sen. Patty Murray, D-Wash., said her college roommate had become pregnant as a result of date rape and had a back alley abortion that left her permanently unable to have children.

But Sen. Kent Conrad, D-N.D., recounted the most chilling personal story as he argued for allowing the government health plans to cover abortions resulting from cases of rape or incest.

“My wife was attacked eight blocks from where we are,” he said as his voice quavered. “It was a vicious rapist, … she had a gun to her head, and he tried to get her into a car. … She was able to evade him.”

If she had become pregnant, “it would be vicious and monstrous to say she had to carry that baby to term,” he said before quickly leaving the chamber.