Today’s case: I have a patient who is doing a frozen embryo cycle, so we are preparing her uterus by giving her estrogen pills. She completed 2 weeks of estrogen therapy and her uterine lining was 6 mm, a ring pattern (also called a triple pattern). We decided the 6 mm was a little thin, so we kept her on the estrogen for 1 more week. I scanned her this morning and her lining was 8 mm. As this was a more acceptable thickness, we didn’t need to wait any longer and we have now scheduled her transfer.
Is this a typical response? Did waiting help her cause? Let’s go over a few things.

Can your doctor do anything to improve the thickness of the lining? First let’s start with things I try. And here I am talking about a “medicated cycle”, one in which a woman is asked to take estrogen to prepare the lining for a frozen cycle or maybe in preparation for a donor egg cycle. These are cases where the ovaries are not stimulated by fertility drugs, there is no egg production and therefore the ovaries do not make estrogen. All the estrogen comes from medications.

One way to try to improve a lining is to just take more estrogen. There are different ways to get estrogen into your body: pills, patches, vaginal pills or suppositories and injections. All work well and none have been shown to be superior. When you are talking purely about estrogen levels, usually the shots and the vaginal pills lead to the highest blood levels. Levels with the oral pills and patches give levels that are a lower, but usually these methods supply more than enough.

What is the minimal acceptable level? I shoot for at least 200 pg/ml, but probably a little lower is just fine. No one has ever shown that 400 is better than 200, or 1000 is better than 400. Therefore, most of us are not overly concerned with the levels as long as the minimum is reached.

So in the case above, we didn’t even add any more, we just gave the uterus more time, and it seemed to work.

I start with estrogen pills, because I think it’s easier for the patients. Some women get bad rashes from the patches, and we all try to avoid injections. The other thing I don’t like about the injections is that the estrogen stays in your system a long time. So if you are not pregnant you need to wait longer to start again. But if you doctor has another preference, fine with me, they all work.

Some women do not absorb the pill well, and other women get low levels with all of the estrogen methods. We don’t know why. Maybe they metabolize the estrogen quickly (their lever breaks it down quickly).

If the pills are not working well, we can add a patch, so the patient is taking both. Or we can add the vaginal pills, injections or all of the above.

Case 2. I had a patient years ago who did one IVF cycle with a lining of 8 mm. She got pregnant and had an uncomplicated vaginal delivery. Nothing unusual happened at all. Then she came back for her frozen embryos and her lining would not go above 4 mm. We added everything, still 4 mm, despite very high blood levels. We cancelled the cycle, and tried another fresh IVF cycle, thinking maybe her uterus would respond better to the ovaries making estrogen, and still 4 mm. We do not know what led to the change.

The point here is that only some women respond to extra estrogen and or time. Most of the time, if you have been on some form of estrogen for 10-14 days, that’s it. What you have you have, there is no improvement later. Or maybe there is a minimal increase the lining thickness.

In many many cases, the “feel sorry” factor comes into play. This is when the doctor does the scan, finds a thin lining, and then looks and looks and looks trying to find you an area that is a little thicker, and usually finds a better spot, even if it’s 1-2 mm extra. When the lining is obviously thick, it should take the doctor about 2 seconds to measure the lining. If it’s thin, but it’s a little early, and we know you will be coming back, same thing. But if you now have had extra time or been on extra estrogen, there is nothing else to offer, and we look and look.

The point here is I don’t know if the lining actually improved. It may just be that the doctor took much more time and found a little area that looks a little thicker and everyone leaves the scan feeling a little bit better.

Next time we will finish with other ways to make the lining thicker, and we will try to answer the question, what is the thickness target?
Thanks again, and please read disclaimer 5/17/06.
Dr. Licciardi


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