"It has long been troubling to many Americans that the nation's largest abortion network, performing over a third of all abortions, receives over half a billion taxpayer dollars a year," said Boston Cardinal Sean O'Malley.
"This concern has rightly grown in recent years," he wrote in a letter to the senators.
The cardinal, who is chairman of the U.S. Conference of Catholic Bishops' Committee on Pro-Life Activities, urged senators to support S. 1881, a measure that would defund Planned Parenthood and its affiliates.
Later that day, the Senate voted 53-46 to stop efforts Republicans said Democrats were using to delay and ultimately kill S. 1881. According to an AP story, 60 votes were needed to enable the defunding measure to move forward.
The Senate action came just days before Congress was to begin its August recess. AP said the House is expected to vote on a similar measure when Congress returns.
O'Malley's letter followed the release in mid-July of videos of the organization's officials filmed undercover by a nonprofit California-based organization called the Centre for Medical Progress.
"The most recent revelations about Planned Parenthood's willingness to traffic in fetal tissue from abortions, and to alter abortion methods not for any reason related to women's health but to obtain more 'intact' organs, is the latest demonstration of a callousness toward women and their unborn children that is shocking to many Americans," he said.
In two of the videos, top Planned Parenthood physicians describe how abortions are carried out to best salvage fetal tissue and organs for researchers and described a range of prices paid for different body parts.
A third video was of an interview with a technician talking about harvesting fetal body parts and included graphic footage.
A fourth video has now been released. A temporary restraining order issued by the Los Angeles Superior Court prohibits the Centre for Medical Progress from releasing any video footage of interviews of officials from StemExpress, a California-based company that provides organs and tissue to researchers.
Planned Parenthood receives more than $500 million of its $1.3 billion annual budget from federal and state programs. According to 2013 data, the latest available, Planned Parenthood says abortions represent three per cent of the total services its facilities provide, which include dispensing birth control and doing some women's health screenings.
In addition to Republicans in the House and Senate pushing for an end to federal funding of Planned Parenthood, several states have launched investigations into the organization.
Cecile Richards, president of the Planned Parenthood Federation of America, in a statement said that "allegations that Planned Parenthood profits in any way from tissue donation is not true." She later apologized for "the tone" the physicians used in describing abortion procedures and also argued the videos had been heavily edited to distort the truth.
Priests for Life announced Aug. 4 that a coalition of religious and pro-life groups plan to lead a "Week of Prayer to End the Evils of Planned Parenthood" Aug. 22-29. Several suggested prayers for the week have been posted at PrayerCampaign.org.
Ohio state Rep. Bill Patmon is among local lawmakers calling for defunding of Planned Parenthood. At the Ohio Statehouse July 29, a crowd cheered as the Cleveland Democrat said he would introduce a measure to strip state funds from the organization.
As an African-American, he also had sharp criticism for the Black Lives Matter movement, organized to protest what its leaders say are racist police tactics that target black Americans.
He expressed his outrage at the number of unborn black babies killed by abortion, compared to other races and labeled Black Lives Matter as hypocritical, saying the group needs to hold protests in front of Planned Parenthood facilities.