GEOFF BENNETT: For years, mifepristone and similar drugs that can induce abortion have been used to treat common, but often debilitating conditions, including uterine fibroids and endometriosis.

Now researchers around the world are exploring whether these drugs could have other uses in women's health, including preventing some cancers.

In the second part of our series beyond abortion, special correspondent Sarah Varney traveled to the U.K.

to look at that potential and how the politics and restrictions surrounding these drugs in the U.S.

could affect the research.

SARAH VARNEY: On a gray summer day in a small village outside of Manchester, England, I met up with Pamela Cachart.

PAMELA CACHART, Medical Trial Participant: This is made here.

SARAH VARNEY: Pam grew up here with her brother Chris (ph) and her mother, Dee (ph).

PAMELA CACHART: She was quite a young woman.

So we were very good friends, best of friends.

My mom was just perfect, amazing, very strong, and incredibly courageous for what she went through.

SARAH VARNEY: At just 43 years old, Dee died from breast cancer.

Decades earlier, Pam's grandmother was killed by the same disease, also in her early 40s.

I think sometimes for women who have a history of breast cancer in their family... PAMELA CACHART: Yes.

SARAH VARNEY: ... you can feel almost fatalistic about it.

PAMELA CACHART: Yes.

SARAH VARNEY: Like, when is it just going to happen to me?

PAMELA CACHART: You can -- you feel like you're looking at the clock, waiting for that moment to happen when, oh, it's me now, this is my turn.

SARAH VARNEY: That's why Pam joined a study aiming to prevent breast cancer in people with a family history before they hit menopause.

So mammogram machine, I'm very familiar with one of these.

Published last year, the trial was led by Dr.

Sacha Howell, an oncologist and breast cancer researcher at the University of Manchester.

Participants were given a drug called ulipristal acetate, or UPA.

It's approved in the U.S.

as an emergency contraceptive and has been shown to end an early pregnancy at higher doses.

The drug blocks the effects of a hormone called progesterone that causes cells in the breast to grow and divide.

DR.

SACHA HOWELL, Oncologist, University of Manchester: The more cell divisions, the more proliferation there is in the breast, the higher the chance that there is going to be a breast cancer.

SARAH VARNEY: Dr.

Howell and his team recruited 24 women, including Pam.

The women all had breast biopsies and MRIs and then took a daily dose of the drug for three months.

Researchers wanted to see if it would block the growth of breast cells that can turn into cancer.

DR.

SACHA HOWELL: We got the message very early that it was going to be successful.

BRUNO SIMOES, University of Manchester: Basically, the important part for us here is that we can see the cells where tumors originate.

SARAH VARNEY: One of Dr.

Howell's colleagues showed me what happened to those problem cells after the women took the drug for just 12 weeks.

DR.

SACHA HOWELL: We saw a reduction in the number and activity of cells that we think go on to cause quite aggressive breast cancers like triple-negative breast cancer.

So we think we may have a treatment here.

But the other thing that we saw was that the architecture, as you put it, of the breast, does change.

SARAH VARNEY: The breast tissue started to relax.

Dr.

Howell says that's important because stiff tissue tells the cells to mutate, which further increases breast cancer risk.

Other researchers are building off this work to see if, by relaxing dense breast tissue with UPA, it will be easier to detect cancer on mammograms.

Is early detection worse for women who have dense breasts?

DR.

SACHA HOWELL: The worry with breast density is that we will actually miss a cancer that is there.

And the recent study in the U.K.

showed that on average about eight women were diagnosed with breast cancer on a mammogram for every 1,000 that had one.

SARAH VARNEY: Wow.

DR.

SACHA HOWELL: And that's with dense breasts.

But a trial like Dr.

Howell's would be hard to replicate today in the United States.

WENDY WRIGHT, Concerned Women for America: So it's important for people to know that this is an abortion drug and that it may end up harming women.

SARAH VARNEY: Anti-abortion activists have targeted ulipristal acetate, or Ella, since it was approved as an emergency contraceptive in 2010.

Those calls increased after a study published last year found a higher dose of the drug can be used for medication abortion.

Why is it that you think it's not available here in the United States?

DR.

LAURA ESSERMAN, University of California, San Francisco: Well, I think, unfortunately, these drugs have gotten caught up in politics.

Because of the pressure from this administration or from others, I think people are concerned that they will be punished for doing this work.

So there's just a very hostile environment to doing research and pushing innovation.

SARAH VARNEY: Dr.

Laura Esserman is a breast cancer surgeon at the University of California, San Francisco.

She worries that holding back research now will mean fewer choices for patients in the future.

DR.

LAURA ESSERMAN: I have spent my life trying to prevent people from dying of breast cancer.

It would be terrible to have women dying of completely preventable causes.

Imagine if we get a contraceptive that reduced your risk of breast cancer by half, and we would maybe have, instead of 325,000 cases of breast cancer, we'd say, have maybe back to 150,000 cases of breast cancer.

How great would that be?

SARAH VARNEY: Last year, one of those hundreds of thousands of cases was Mary Benjamin.

MARY BENJAMIN, Medical Trial Participant: When I was diagnosed, I'm sure, like most people who were diagnosed with cancer, it's like, oh, cancer, is this a death sentence?

SARAH VARNEY: The 57-year-old came to New York from Egypt three decades ago.

Last year, she was diagnosed with triple-negative breast cancer, which is known to be aggressive and difficult to treat.

It's the type of cancer Dr.

Sacha Howell says UPA might help prevent.

MARY BENJAMIN: I have daughters.

I have a granddaughter.

I have nieces.

I have a sister.

So it means so much to me if I can prevent their cancer journey.

So having an option to take to take that medication in advance to prevent their chance of getting any type of cancer, and specifically breast cancer, is a win-win.

SARAH VARNEY: Mary is a Christian and against abortion.

Is it possible to be -- to be opposed to abortion rights, but also want those drugs to be studied specifically for breast cancer?

MARY BENJAMIN: Absolutely.

And being anti-abortion, it doesn't mean I'm going to stop every woman from taking that.

So at least we can study it on women who choose to do that, especially in states where they are allowed to do that.

So, yes, I am against the politics coming in the way of science.

DR.

LAURA ESSERMAN: These drugs are approved.

They have been in use.

We know they're safe.

They have been out there for decades.

SARAH VARNEY: Dr.

Esserman points to multiple studies outside of the United States that show the abortion drug mifepristone could also be effective in preventing breast cancer, particularly for those with the BRCA gene mutation, which increases cancer risk.

And other research is demonstrating these anti-progestin drugs have the potential to reduce the risk of ovarian cancer.

WOMAN: That's wild.

DR.

LAURA ESSERMAN: Isn't that something?

SARAH VARNEY: But Dr.

Esserman says political leaders need to help advance, not hinder, that science.

DR.

LAURA ESSERMAN: I want to be able to stop saying to people, I'm so sorry that you have breast cancer.

But there has to be signaling from the administration that this is going to be and from the FDA that this is going to be safe, that, if we show that there's an effect, that someone's going to approve the drug.

No one is going to invest in making these medicines available if they can't get them approved.

DR.

SACHA HOWELL: There are some fantastic collaborators that I got in America, and I would love to open the study over there.

I think that would be a huge uphill struggle given the current political climate.

SARAH VARNEY: Dr.

Howell says, in the meantime, European researchers will push ahead with the backing of their governments.

DR.

SACHA HOWELL: Politics is intimately involved with science, because so much science is funded by central governments.

So I don't think we can really disentangle politics from science.

But I think we do have a problem when politicians start to dabble with things that they don't really understand.

And I think that's where I would try and draw the line.

SARAH VARNEY: It's been nearly seven years since Pamela Cachart was involved in Dr.

Howell's study.

PAMELA CACHART: I think the progression of the medicines is amazing.

I think that needs to just continue, a quicker rate, if it can do.

Moving aside from the politics, if we can just keep going and keep trialing these medicines, we're going to be in a lot better position in 20 years' time to what we are today.

SARAH VARNEY: Pam says she benefited from people who volunteered for previous drug trials.

And now she's paying it forward.

PAMELA CACHART: It's unfortunate that I have got this family history.

However, in some ways, it's a gift that I'm being able to trial the medicines, and then, going forward, that might help my nieces and their nieces or their children in the future.

And if you can help someone else, why wouldn't you do it?

SARAH VARNEY: For "PBS News Hour," I'm Sarah Varney in Cheshire, England.