Intrauterine contraceptive devices (IUDs) have been linked to increased background enhancement on breast MRI, according to research presented at the Radiological Society of North America 2021 annual meeting.
About 10.4% of women 15-49 years of age who use contraception have an IUD or contraceptive implant, according to the Centers for Disease Control and Prevention. Unlike oral or transdermal hormonal contraceptives and hormone replacement therapy, levonorgestrel-releasing IUDs release a small amount of the hormone directly into the uterus and are thought to have a much more localized effect, Luisa Huck, MD, the lead author of the study, said in an interview.
But women with IUDs have long reported adverse effects associated with other hormonal medication. “In the past, some women reported depression, headaches, sleep disorders, and panic attacks,” noted Dr. Huck, a radiology resident at RWTH Aachen University in Germany.
Christiane Kuhl, MD, chief of the department of radiology at RWTH Aachen University and senior author of the research, had also observed that women with hormonal IUDs often have increased background parenchymal enhancement (BPE) on contrast-enhanced MRI. BPE “has been established as a sensitive marker of hormonal stimulation of breast,” the study authors wrote, and previous studies have shown that women using hormonal medications have higher BPE on breast MRIs.
To better understand whether IUDs can increase BPE, Dr. Huck and colleagues used the hospital database to search for premenopausal women who had undergone breast MRIs for screening between January 2014 and July 2020. To be included, women had to have had at least two scans: one with and one without an IUD in place, with the scan conducted at least 4 weeks after IUD placement or removal. All women in the study had no history of breast cancer or hormone or antihormone intake.
The study involved 48 women with an average age of 45 years and a median of 27 months between the two scans. Forty-six of the women had the Mirena levonorgestrel-releasing IUD and two had the Jaydess IUD. To account for hormone variations between patients, the researchers used each patient as their own reference point. To control for age-related effects, 25 women had their first MRI without an IUD and their second scan with an IUD in place. The second group of 23 women underwent their first MRI with an IUD and had it removed before the second scan.
Hormonal effects on breast enhancement are very complex, and hormonal stimulation is not always predictably correlated with changes on MRI imaging.
For 23 women in the study, background enhancement was higher on scans with the IUD than without (P < .001). For 24 women, there was no change in BPE with or without an IUD, and one woman had lower BPE with an IUD than without.
“It is very interesting and relevant to practice to consider that the presence of an intrauterine device would have potential impact on the enhancement we see in the breast on MRI imaging,” Samantha Heller, MD, PhD, associate professor of radiology at New York University, said in an interview.
However, the study used BPE as a measure for hormonal shifts, and “hormonal effects on breast enhancement are very complex, and hormonal stimulation is not always predictably correlated with changes on MRI imaging,” she noted. BPE on MRI can fluctuate, so testing actual hormone levels in patients with elevated BPE could be helpful to identify hormonal shifts, she added. It is also important to understand why half of the women in the study showed no variation in BPE, she said.
The study findings are not very surprising, considering that it is known that low levels of progesterone from IUDs circulate in the blood stream, Frances Casey, MD, MPH, associate professor in the department of obstetrics and gynecology at Virginia Commonwealth University in Richmond, said in an interview. They do not suggest that there should be any changes to IUD guidelines, she added.
However, “the study findings raise the question as to whether IUD status should be documented as a matter of course prior to performing breast MRI,” said Dr. Heller. “It is standard to document the timing of a woman’s menstrual cycle, as well as to note any hormone suppression or replacement therapy. This is in part so that the radiologist may understand the etiology of any observed variation in background enhancement,” she explained.
Although increased enhancement on MRI has sometimes been linked to higher chances of recommendations for additional imaging or biopsies, she noted, “more work would be needed to understand the impact – if any – of an IUD on breast MRI recommendations due to enhancement changes.”
Dr. Huck, Dr. Heller, and Dr. Casey disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.