Breast MRIs reveal systemic effects of IUDs

Intrauterine contraceptive devices appeared to have systemic effects on the body akin to those associated with hormone replacement therapy, a small study showed.

Although women have previously reported experiencing adverse events after receiving an intrauterine contraceptive device (IUD) that were similar to adverse events associated with oral hormonal replacement, “manufacturers claim that IUDs have a purely local effect on the uterus,” Luisa Huck, MD, a radiology resident in the department of diagnostic and interventional radiology at RWTH Aachen University in Germany, said in a statement.

“Our study results suggest that this is not true,” she said.

The study was conducted after Christiane Kuhl, MD, chief of the department of radiology at RWTH Aachen University, observed that women with a hormonal IUD frequently had higher background parenchymal enhancement on contrast-enhanced breast MRIs. Background parenchymal enhancement is a sensitive marker of hormone levels, according to a press release.

To investigate the observations, the researchers evaluated standardized dynamic contrast-enhanced breast MRIs that were performed on 48 premenopausal women with no personal history of breast cancer who had not received hormones or antihormones. All the women had undergone two MRIs between January 2014 and June 2020. One MRI was performed while an IUD was in place, while the other MRI was performed in the absence of an IUD. There was a minimum duration of 4 weeks after IUD placement or removal and the MRI. The mean age of the women was 45 years, and the median time between the participants’ two MRIs was 27 months.

“To avoid confounding aging-related effects on background parenchymal enhancement, half of included women had to have their first MRI without, the other half had their first study with IUD in place,” the researchers wrote.

The American College of Radiology’s definitions of background parenchymal enhancement were used to interpret the findings.

Huck and Kuhl reported at the annual meeting of the Radiological Society of North America that background parenchymal enhancement was significantly higher while an IUD was in place in 48% of the women (95% CI, 33.9-62.1), “indicating that there are hormonal effects caused by IUD use that occur well beyond the uterus,” according to the press release. However, the researchers noted that one woman’s background parenchymal enhancement level decreased with the IUD.

“Use of an IUD leads to hormonal stimulation of the breast that is detectable by MRI,” Huck said in the release.

Although the findings suggest that IUDs may impact the diagnostic accuracy of breast MRIs, the study does not indicate that IUDs are unsafe, Huck said.

References:

Breast MRI shows IUDs have systemic effects. https://www.eurekalert.org/news-releases/935138. Published Nov. 22, 2021. Accessed Nov. 23, 2021.

Huck L, et al. Background parenchymal enhancement in contrast-enhanced MR imaging suggests systemic effects of intrauterine contraceptive devices. Presented at Radiological Society of North America Annual Meeting, Nov. 28 to Dec. 1, Chicago.