After Breast Cancer, Scientist Wants Women to Know Mirena’s Risks

Paula Szum wanted birth control that would make life a little easier. She was active, her children were young and she liked the idea of not having to think about contraception. She had her first Mirena intrauterine device (IUD) inserted at age 36. Seven years later, at 42, she had it replaced.

Having worked as a forensic scientist for many years, Paula trusted data and understood research. With her scientific background, she considered herself very educated on drug side effects and warnings.

But Paula says she didn’t receive a warning about a possible connection between hormonal birth control and breast cancer. She believes that information would have changed her decision.

“If [my doctor] had told me that, I would have said, I’m not putting that in my body,” Paula told Drugwatch.

After treatment for two different types of breast cancer, she hopes that women will research hormonal birth control and ask questions before deciding what is right for them.

Paula’s diagnosis began with something she found herself: a nodule beneath her left breast. She initially wondered whether it might be skin cancer, but doctors identified it as ductal carcinoma that had reached the skin.

During her evaluation, doctors also found an area of concern in her right breast. The cancers were different: One was driven by estrogen and progesterone, while the other was driven by estrogen alone.

Her doctor did not tell her that Mirena may have caused the cancers. According to Paula, the care team removed the IUD because they did not want to expose her body to more progestin, a synthetic hormone meant to mimic the effects of progesterone.

Recent research has given Paula context for her concerns.

Mirena releases levonorgestrel, a synthetic form of progesterone. A 2024 Danish study involving nearly 158,000 women found that users of levonorgestrel-releasing IUDs had a 40% higher relative risk of breast cancer than women who did not use hormonal contraceptives. Researchers estimated this represented 14 additional breast cancer diagnoses per 10,000 users. The study did not find that the risk increased significantly with longer use.

Another study in the American Journal of Obstetrics and Gynecology examined health records from more than 500,000 levonorgestrel IUD users in Sweden. Researchers found a 13% higher risk of breast cancer among users compared to women who did not use the devices. The authors characterized the increased risk as small but emphasized that the findings should be considered alongside the IUD’s protective associations with some gynecologic cancers.

Both studies were observational, meaning they identified associations but could not establish that levonorgestrel-releasing IUDs caused breast cancer. However, the findings helped explain why women like Paula question the role their IUDs might have played in a cancer diagnosis.

Paula had no family history of breast cancer. She even did genetic testing to assess her BRCA genes, which produce proteins that help repair damaged DNA. Abnormalities in these genes may heighten the risk of breast and other cancers, but Paula tested negative for gene mutations. She maintained a healthy weight,did not drink or smoke, and breastfed her children, which some studies suggest reduces breast cancer risks.

Paula had a chemotherapy port placed, but she was uncomfortable with the first oncologist’s treatment plan. As a forensic scientist, she was familiar with reading reports. After going over the results of her radiology tests with her doctor, she noticed a few questionable areas around both her breasts. She wanted to make sure all potential problem areas were addressed. So, she pushed for a double mastectomy — surgical removal of both breasts — instead of undergoing additional biopsies.

A breast surgeon supported her choice and referred her to Northwestern Memorial Hospital, which was recently ranked #8 nationally and #1 in Illinois for cancer treatment by U.S. News and World Report. There, doctors agreed that the surgery would give them a more complete picture of the cancers. After the mastectomy, her team tailored her chemotherapy regimen. She received eight treatments rather than the 16 treatments initially proposed by her first provider.

During treatment, Paula also used acupuncture because she was worried about neuropathy. She met with physical and occupational therapists for exercises to preserve her range of motion.

Today, Paula is in a survivorship program and takes Verzenio and letrozole, two drugs that treat or help prevent hormone-related breast cancers from coming back.

Staying active has been central to Paula’s recovery. She enjoys kayaking, running, yoga, stretching, and walking with her dogs and after meals.

But shortly after her diagnosis, she felt sorry for herself. Curled up on her bed, she told a family member that she didn’t think she was long for this world. But in that moment of despair, she was jolted forward toward resilience.

She described two types of people. Those who feel sorry for themselves, and those who get up in the face of adversity and keep moving.

“I’m going to get up, and I’m going to fight this with everything I’ve got. And that’s the mindset I went into with this,” she said.

That approach continues to guide her. “Your mindset’s at least half of it,” Paula said.

Paula hopes that she can help advocate for stronger research and clearer warnings so women can make informed decisions about hormonal birth control.

“I’m not in it for the money,” she said. “I’m in it for slapping [the drug] with a big warning label.”

She worries for mothers with young children, who may face the same fear and disruption that followed her own diagnosis. She is passionate about helping other women in similar situations.

Her advice to people considering Mirena or another form of hormonal birth control is direct: “Do your research.” She also urges partners to communicate about contraception and weigh alternatives together.

Paula cannot change what happened, but she is determined to use her experience to help someone else.

“It happened,” she said, “so I’m going to make the best of it.”