Thin Endometrial Lining
Embryos need to implant in the Endometrium, and an optimal Endometrium is thick and Trilaminar. The fertility problem arises when the patient has a poor Endometrium or a thin uterine lining. This could lead to low estrogen levels, poor blood flow or damaged Eendometrium.
The frustrating problem of a thin uterine lining
As an IVF specialist , I often see infertile patients with complex and unusual problems. One of the most challenging problems to deal with is that of the patient with a poor endometrium or a thin uterine lining. Embryos need to implant in the endometrium , and an optimal endometrium is thick and trilaminar.
A normal endometrium requires adequate blood flow ; and high estrogen levels. Thus , if the lining is thin there are 3 possibilities: the estrogen levels may be low; the blood flow is poor; or the endometrium is damaged. We need to systematically examine all these 3 possibilities , so that we can pinpoint what the problem is in the individual patient , and then try to correct it.
If the doctor finds the endometrium is poor during the IVF cycle , often the best option is not to transfer the embryos but to freeze all of them. The patient can then be treated with high doses of exogenous estrogens, to see if this causes the endometrium to become thick. If the endometrium grows well , it's then possible to transfer the frozen embryos after thawing them into an estrogen primed endometrium.
However if the lining remains thin in spite of high doses of estrogen, this means the problem is either one of poor blood supply ; or a damaged endometrium. Some doctors have used color Doppler ultrasound to measure uterine blood flow, but the results with this have been mixed. Others have tried using vaginal viagra to try to improve endometrial blood flow. Since there is no reliable method to assess uterine blood flow , the next step is to determine whether the endometrium has been damaged or not. There are two possible causes of end-organ damage when the endometrium is nonresponsive. One is that the endometrium has been anatomically distorted because of intrauterine adhesions ( a common cause for this in India is uterine tuberculosis. This condition is called Ashermann syndrome; and this can be diagnosed either with a hysterosalpingogram , which shows filling defects within the uterine cavity ; or with hysteroscopy , during which procedure the scars can be surgically removed. However in some patients , even though the uterine cavity is anatomically completely normal ; the uterine blood flow is normal; and the estrogen levels are high, the endometrium remains persistently and frustratingly thin. We then hypothesize that the endometrium has suffered end-organ damage as a result of which it does not respond to estrogens. This condition has never been adequately studied; and it does not even have a name ! Most doctors just call it - " Thin endometrium" . The Latin equivalent for this would be leptometrium ( lepto = thin) . Maybe we should coin a name to describe this condition , so that we can study it properly. Today, this can be an unsatisfying diagnosis to make, because we cannot prove this diagnosis ; and neither can we correct this problem. The only solution for some of these patients is surrogacy.
