As Planned Parenthood celebrated its 100-year anniversary over the weekend, its president Cecile Richards said the organization has become “stronger” despite the “attacks.”

Planned Parenthood has suffered major blows when some of its facilities had to close after funding was cut off in some states. The leaked video regarding the sale of fetal parts has also affected the organization negatively. However, Richards said these events did not weaken the organization.

"The attacks have only strengthened our resolve," Planned Parenthood president Cecile Richards said, according to the Associated Press. "I do believe we are in a stronger place today than a year ago, or five years ago."

In an op-ed article for Time, Richards revisited the organization’s beginnings through birth control activist and founder Margaret Sanger. Richards said Sanger’s vision was to enable women to live healthier lives by helping them control the spacing between their children or giving them the option not to have children if they desired.

“Birth control, as well as access to safe and legal abortion, has opened up possibilities for women’s lives that few could have imagined in 1916,” Richards wrote. “Today, because contraception is more effective, more accessible and more affordable, the U.S. is at a 30-year low for unintended pregnancy, and a historic all-time low for teen pregnancy.”

While Planned Parenthood marked its centennial with the hashtag #100YearsStrong, a coalition of 11 pro-life groups tagged it as #100YearsOfAbuse. The anti-abortion coalition said Planned Parenthood, which receives an annual fund of more than half a billion dollars, is responsible for 324,000 abortions every year.

In a joint statement published on the website of the pro-life advocacy group Americans United for Life, the pro-life coalition criticized Sanger’s “anti-poor” stance, saying she “advocated for the eradication of poor and disadvantaged, whom she considered less-than-human ‘weeds.’”

“Planned Parenthood’s 100-year anniversary is a tragic milestone for our nation and a reminder of the millions of unborn children who will never have a birthday. We mourn these children, as well as the women who have been hurt and exploited by the nation’s largest abortion chain,” the statement said.

Pro-life groups, led by Pro-Life Action League, also held prayer vigils in over 100 of the organization’s facilities during the weekend.

Eric Scheidler, director of Pro-Life Action League, said it’s “hard to imagine a quick end to abortion.” He said the fight against abortion could be likened to the fight against slavery, which was tolerated for centuries before it was finally stopped.

“To truly eradicate this evil from our society is going to take a massive transformation of our culture itself, not unlike the Great Awakening,” Scheidler said, according to The Washington Times. “Slavery was tolerated for hundreds of years, and there were people from time to time speaking out against it. But it wasn’t until the Second Great Awakening in the early 19th century that the emancipation movement really began to have some real political power and cultural power.”

Planned Parenthood and the issue of abortion are at the center of the 2016 US presidential election. Democratic nominee Hillary Clinton has said that she will be the organization’s partner “for the long haul,” while Trump threatened to cut off its funding if it would continue to provide abortion services.