Despite the many advancements in science and technology that have been game-changers in the fertility field, there is still so much that is unknown. Even now, roughly 30% of couples seeking reproductive assistance have unexplained fertility. It’s extremely frustrating to not know why you can’t conceive, so I’m thankful to the lady scientists behind this week’s fertility article who posed some good questions. These questions were, how long lasting are the effects of the levonorgestrel IUD after its removed, and how does this IUD impact the future fertility of women who’ve never before had a baby?

Hello, this is “Your Fertility Pharmacist.” This podcast is for women who are trying to overcome infertility. If you keep a pulse on late-breaking fertility research, it could positively alter the course of your fertility journey, as it has for me.

This week’s article was written by Erin Dinehart, Ruth B. Lathi, and Lusine Aghajanova. It was published in the Journal of Assisted Reproduction and Genetics in November 2019.

The Mirena was the first levonorgestrel IUD approved in the U.S. in late 2000. Since then, other levonor IUDs have come out, including Liletta, Skyla, and Kyleena. They all look and act essentially the same. These IUDs will send out a low-level of progesterone, which will make the uterine lining thicken in the cervix. Kind of like a super stuffed up nose in which nothing seems to go in or out easily, the cervix is so plugged up with mucus from this IUD that the sperm can’t easily swim around. Beyond doing its job as a Sperm Stopper, the levonorgestrel IUD also can impact ovulation for up to one year after insertion.

Research has shown that the levonor IUD’s impact on fertility is reversible, BUT there are questions on how quickly fertility returns and to what extent. A 1992 study spent almost two years tracking 140 women who had used a Levonor IUD for an average of 19 months. After the IUD was removed, the pregnancy rates after twelve months of trying were 75.4%, which is lower than the general population, which is 85-92%. Moreover, the 1992 study combined women who had already conceived with women who had never conceived, which makes it harder to tease out the results for women who were trying to have their first baby. A more recent study from 2017 showed similar results - after removing the IUD, 71.2% of women conceived within twelve months. This 2017 study also lumped together the women who had previously given birth with women who hadn’t. So, we still don’t really know how levonor IUDs impacts women who have never had children before and/or women who used the IUD for closer to five years, which is how long Mirena and Kyleena can safely stay inserted.

I just searched clinicaltrials.gov to see if any new studies will be coming out soon with answers to these questions. There were 144 clinical trials related to levonorgestrel intrauterine devices, and NONE of the trials are studying the impact on fertility in women who would be first-time moms. There were studies looking at the satisfaction of women using levonor IUDs, but these studies were also limited to twelve months after IUD insertion.

To conclude, it’s possible that the IUD has a lasting impact on the tissue of the endometrium even after being removed, which may impact fertility. It’s also possible that the IUD impacts fertility differently for women who have already conceived vs. women who have never conceived. We don’t know, so I’m glad that the scientists publicly posed these questions.

I wish I had thought to look into the potential long-term consequences on my fertility before signing up for five years of the Mirena. If I was going to repeat getting an IUD now, I would probably select one that is indicated for three years, given that the data is more closely comparable to three-years vs. five or six years of keeping a levonor IUD in.