It does not have the same effect on osteoporosis as GnRH-a (the gold standard medicine used for endometriosis) and does not stop the ovaries from ovulating in all women (as does GnRH-a).
A Cochrane Review article from earlier this year noted, the IUD might also be good at reducing painful periods if inserted after surgery for endometriosis. And just last month, the FDA approved Mirena’s use for heavy periods, a cardinal symptom in endometriosis.
So far, no studies have shown a downside to using the hormonal IUD for endometriosis symptoms, but it’s worth noting that this is still new territory in the research world. The gold standard, GnRH-a, is still the gold standard and that might be because some studies have questioned the IUD’s ability to shrink an enlarged uterus (also common in endometriosis).
Lastly, the economy being what it is, it’s also smart to look at the cost effectiveness of the IUD. It might actually be cheaper to have your Ob/Gyn insert a Mirena IUD (that costs around $800 each and lasts up to five years) versus monthly injections of GnRH-a (that can run hundreds of dollars per month).
For reproductive aged women with endometriosis who are not trying to conceive, the progesterone IUD could be the solution for pain or, at the very least, a hopeful possibility.