In a move that could boost efforts to limit population growth, Republicans in Congress agreed yesterday to lift a restriction that now bars international family planning groups that receive some U.S. funding from spending any of their own money to promote abortion rights or provide legal abortion services. Family-planning advocates have long argued that the restriction hampers even groups that focus primarily on providing alternatives to abortion and may, ironically, lead to increased abortions. Congressional negotiators, who want to avoid a pre-election clash with President Clinton, also agreed to increase the money going to international family planning groups from $385 million to $425 million. But the money could not be spent until Feb. 15, after the next president takes office. Abortion opponents are hoping that George W. Bush will win the election and reinstate the abortion restrictions.