Dr. Goldstein: If you look in the package insert for Mirena,2 similar to Liletta, certainly the serum levels of LNG are lower than that for combination oral contraceptives. For the IUD progestins, they are not localized only to the uterus, and LNG levels range from about 150 to 200 µg/mL up to 60 months. It’s greater at 12 months, at about 180 µg/mL,at 24 months it was 192 µg/mL, and by 60 months it was 159 µg/mL. It’s important to realize that there is some systemic absorption of progestin with progestin IUDs, and it is not completely a local effect.
JoAnn, you mentioned the WHI data,25 and just to specify, it was not the estrogen-only arm, it was the conjugated equine estrogen-only arm of the WHI. I don’t think that estradiol alone increases breast cancer risk (although there are no good prospective, follow-through, 18-year study data, like the WHI), but I think readers need to understand the difference in the estrogen type.
Endometrial evaluation. My question for the panel is as follows. I agree that the use of the progestin-releasing IUD is very nice for that transition to menopause. I do believe it provides endometrial protection, but we know from other studies that, when we give continuous combined HT, about 21% to 26% of patients will experience some bleeding/staining, responding in the first 4-week cycles, and it can be as high as 9% at 1 year. If I have a patient who bleeds on continuous combined HT, I will evaluate her endometrium, usually just with a simple transvaginal ultrasound. If an IUD is in place, and the patient now begins to have some irregular bleeding, how do you evaluate her with the IUD in place?
Dr. Levy: That is a huge challenge. We know from a recent paper,28 that the endometrial thickness, while an excellent measure for Caucasian and European women, may be a poor marker for endometrial pathology in African-American women. What we thought we knew, which was, if the stripe is 4 mL or less, we can forget about it, I think in our more recent research that is not so true. So you bring up a great point, what do you do? The most reliable evaluation will be with an office hysteroscopy, where you can really look at the entire cavity and for tiny, little polyps and other things. But then we are off label because the use of hysteroscopy with an IUD in place is off label. So we are really in a conundrum.
Dr. Pinkerton: Also, if you do an endometrial biopsy, you might dislodge the IUD. If you think that you are going to take the IUD out, it may not matter if you dislodge it. I will often obtain a transvaginal ultrasound to help me figure out the next step, and maybe look at the dosing of the estrogen and progestin—but you can’t monitor an IUD with blood levels. You are in a vacuum of trying to figure out the best thing to do.
Dr. Kaunitz: One of the hats I wear here in Jacksonville is Director of GYN Ultrasound. I have a fair amount of experience doing endometrial biopsies in women with progestin IUDs in place under abdominal ultrasound guidance and keeping a close eye on the position of the IUD. In the first dozen or so such procedures I did, I was quite concerned about dislodging the IUD. It hasn’t happened yet, and it gives me some reassurance to be able to image the IUD and your endometrial suction curette inside the cavity as you are obtaining endometrial sampling. I have substantial experience now doing that, and so far, no problems. I do counsel all such women in advance that there is some chance I could dislodge their IUD.
Dr. Goldstein: In addition to dislodging the IUD, are you not concerned that, if the pathology is not global, that a blind endometrial sampling may be fraught with some error?
Dr. Kaunitz: The endometrium in women with a progestin-releasing IUD in place tends to be very well suppressed. Although one might occasionally find, for instance, a polyp in that setting, I have not run into, and I don’t expect to encounter going forward, endometrial hyperplasia or cancer in women with current use of a progestin IUD. It’s possible but unlikely.
Dr. Levy: The progestin IUD will counterbalance a type-1 endometrial cancer—an endometrial cancer related to hyperstimulation by estrogen. It will not do anything, to my knowledge, to counterbalance a type 2. I think the art of medicine is, you do the best you can with the first episode of bleeding, and if she persists in her bleeding, we have to persevere and continue to evaluate her.
Dr. Goldstein: I agree 100%.
Dr. Pinkerton: We all agree with you. That’s a really good point.
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