The policy, which took effect on Wednesday, requires most employers to cover contraception in their healthcare plans without a co-pay.
The mandate has been challenged extensively in court.
Twenty-five lawsuits have been filed against it so far, mostly by groups who object to birth control or consider some forms of it to be abortion.
But that litigation "may take years," Cardinal Daniel DiNardo warned in a letter to members of Congress. He said lawmakers should act against the mandate "before it completes its business this year."
"The fundamental importance of the religious freedom issue at stake demands a timely congressional response," wrote DiNardo, the chair of the U.S. bishops’ Committee on Pro-Life Activities.
"Timely and uniform protection of these rights cannot be expected from the current lengthy judicial process."
The White House policy exempts churches and houses of worship, and allows women who work for religiously affiliated groups to receive free birth control directly from their insurers.
Opponents of the mandate, including Republican leaders in Congress, say the rule tramples on religious freedom and the Constitution.
The debate took on a strong political dimension this spring, when federal health officials released further details on the rule.
Sen. Roy Blunt (R-Mo.) responded with a measure that would allow any employer to opt out of healthcare coverage mandates that violate their religious beliefs. The Senate killed the proposal in a vote of 51-48.
In the House, a recent Labor appropriations bill included a similar conscience provision, but DiNardo said that, too, would come too late.
Any congressional action against the mandate would prompt a veto by President Obama. It is also unlikely the Democrat-controlled Senate would vote to undercut the policy.