Here is an overview of the study presented at the 2021 annual meeting of the Radiological Society of North America (RSNA), which probed the systemic effects that IUDs may have on the body, and if they could be similar to hormone replacement therapy. 

What do the breast MRIs reveal?

In a breast MRI study presented at the 2021 annual meeting of the Radiological Society of North America (RSNA) on 22 November 2021, researchers at the Department of Diagnostic and Interventional Radiology at RWTH Aachen University in Aachen, Germany have shown that hormonal intrauterine contraceptive devices (IUDs) appear to have systemic effects on the body like those of hormone replacement therapy. The presently accepted claim is that IUDs have a purely local effect on the uterus.

The researchers revealed in their paper at the RSNA meeting:

"In theory, this limited area of release means that any side effects would be confined to the region around the IUD. However, emerging evidence suggests that LNG-IUDs can be associated with systemic side effects similar to those of systemic hormonal medication."

The inspiration for the study came from a finding by Christiane Kuhl, M.D., a leading breast cancer researcher and chief of the Department of Radiology at RWTH Aachen University who noticed that women with a hormonal IUD in place often show higher background parenchymal enhancement on contrast-enhanced breast MRI. Background parenchymal enhancement- the initial enhancement of normal breast tissue, is a sensitive marker of hormone levels.

The observation prompted Luisa Huck, M.D., a radiology resident in the Department of Diagnostic and Interventional Radiology at RWTH Aachen University in Aachen, Germany to investigate the association between LNG-IUD use and background parenchymal enhancement in breast MRI and explore possible systemic effects of LNG-IUDs.

The study

Dr Huck and colleagues used the hospital database and identified premenopausal women without a personal history of breast cancer or hormone or antihormone intake, who had undergone standardised dynamic contrast-enhanced breast MRI for screening at least twice.

According to Dr Huck:

“By comparing the level of contrast enhancement in the same women with and without the IUD in place, a change in systemic hormone levels due to the IUD could be traced."

Half of the women in the study underwent the first breast MRI exam before IUD placement and the second with the IUD in place. The other half had their first MRI with IUD placement and the second MRI after IUD removal. The researchers thus avoided age-related effects on background parenchymal enhancement that might affect the interpretation of the results.

The researchers showed that IUD use led to a significant increase in contrast enhancement in 23 of 48 patients, highlighting the fact that there are hormonal effects caused by IUD use that occur well beyond the uterus.

Dr Huck concluded,

“The results suggest that IUDs do not have a purely local effect on the uterus – but affect the entire body. It may very well be that IUDs can have side effects similar to that of other hormonal treatments. The use of an IUD leads to hormonal stimulation of the breast that is detectable by MRI."

She clarified, that the increased enhancement also has implications for the diagnostic accuracy of breast MRI in women using hormonal IUDs. A notable point is that the devices release a small amount of hormone into the uterus. Because the device releases hormone directly into the uterus, the amount in the bloodstream is lower than with other hormonal methods.

While the results point to a systemic hormonal effect for women with IUDs in place, it does not mean that the contraceptives are unsafe to use, Dr Huck emphasised.

Safety and effectiveness

As per Dr Huck:

“IUDs appear to be a very safe means of contraception and are generally well-tolerated. However, if women with an IUD in place experience unexplainable side effects, they should talk to their doctor and consider using other types of contraception."

Tens of millions of women use levonorgestrel-releasing IUDs (LNG-IUDs) worldwide. It is a contraceptive method that combines the advantages of both hormonal and intrauterine contraception.

According to the WHO, the device is equally effective in women of all ages and when using the pill, patch or vaginal ring, younger women have significantly higher contraceptive failure rates than older women.

Other potential advantages of the levonorgestrel-releasing intrauterine device include its role in treating menorrhagia (heavy menstrual bleeding) and dysmenorrhoea. Dysmenorrhoea is the medical term used to describe painful menstrual periods. It is appropriate that such devices deserve closer examination.

This article was originally published on 9 December 2021.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

Dr K S Parthasarathy is a former Secretary of the Atomic Energy Regulatory Board and a former Raja Ramanna Fellow, Department of Atomic Energy. A Ph. D. from the University of Leeds, UK, he is a medical physicist with specialisation in radiation safety and regulatory matters. He was a Research Associate at the University of Virginia Medical Centre, Charlottesville, USA. He served the International Atomic Energy Agency as an expert and member in some of its Technical and Advisory Committees.