Mirena: clear, informative review article
Things you probably already know:
* The Mirena prevents ovulation 5-15% of the time
* "Plasma estradiol (E2) and progesterone measurements are comparable to those of normally ovulating women."
* Mirena is effective at thinning the endometrium for 7 years, but the cervical mucous starts being less protective at 5 years. It's still 99% effective for 7 years, though.
* PID risk is as low or lower than women without IUDs.
* Ectopic pregnancies too--the "more likely to be an ectopic" belief is a quirk of statistics.
* Perforation estimate: 0 to 1.3 per 1000 insertions
* "The US LNG-IUS labeling was revised in 2008. 10 Under indications and usage, it states that “Mirena is recommended for women who have had at least one child.” However, nulliparity is not listed as a contraindication to use of the LNG-IUS in the package insert," and the WHO says NP women can use it.
* Inserting halfway through the cycle actually is correlated with easier settling-in.
* "Amenorrhea occurs in 15% to 20% of LNG-IUS users during the first year of use, and increases to 30% to 40% with longer durations of use."
There are also interesting conclusions about insertion techniques, off-label usage, bleeding changes, post-removal fertility and a bunch more.
Quick poll: Who was told their Mirena lasted 7 years? What year and country did you get yours? I got mine in June 2010 from a USA PP, and was told 5 years, but a friend got hers in August from a secular hospital (also in Portland, OR) and was told 7.
Also, if anyone knows of a study on Mirena 7 year effectiveness that was entirely conducted in the late 90s/2000s, I'd love to read it. The ones discussed in this paper date back to older studies, which may have used a prototype of the Mirena with slightly more LNG.
My undergraduate degree is in evolutionary biology, so while I can read a scholarly scientific paper, medical ones are usually above my head and beyond my patience. But this one is pretty easy to read!