The importance of the endometrium lining

In this article, we discuss the importance of the endometrium. After all, you can have what appears to be the perfect embryo, but if there are problems with the lining of your endometrium, then it may not implant.

We turned to Dr Roukoudis, gynaecologist and fertility expert at IVF Spain to explain.

Dr Roukoudis, can you start by telling us what is the importance and role of the endometrium?

The endometrial condition, together with embryo quality, are the two most important factors for a successful embryo implantation. During a woman’s cycle, under the hormonal influence of oestrogens at the beginning and progesterone afterwards, the endometrium changes so that the perfect conditions for embryo implantation prevail.

Can you tell us about the endometrium thickness: Why is it so important? Is there a minimum thickness? Can it be too thick?

As we said, the endometrium grows under the influence of hormones during the cycle. This growth is essential because the embryo must have enough tissue to implant. Regarding the minimum thickness, there is no strict dogma on this and one should not commit to exact numbers as consistency is also important. But if possible, 8mm should be achieved.

In terms of an endometrium being too thick, again, there are no rules. Here, what we have to take into account is the curving line of the endometrial lining and receptivity for implantation. If the thickness is already superior to normal values during the cycle, it might mean that the lining will decrease by the day of the transfer, which won’t allow the embryo to implant. The key is to find the perfect moment for each patient to proceed to the embryo transfer.

How do you as a doctor increase the thickness of the lining if it isn’t quite thick enough?

All our patients have a personalised hormonal stimulation and lining preparation, all very monitored so we can adjust medication. For treatments using egg donors, patients undergo a mock cycle while we find and synchronise their donor, so we can know their lining in advance and adapt even more their protocol to their needs for the real cycle. Here at IVF Spain we use a step-by-step protocol that ranges from high-dose oestrogens and gonadotropins to regenerative treatment approaches.

Is there anything the patient can do themselves to improve the thickness?

Well… not really actually. A healthy lifestyle as always is helpful for your whole body preparation, but there is no specific trick for the endometrium lining.

If the endometrium just won’t thicken, what happens then?

This could be especially the case in patients with Ashermann’s Syndrome. Nowadays, we have many options as mentioned, even endometrial regeneration with PRP that we do here in IVF-Spain. Even if it takes us several cycles to get there, it is now very unlikely we won’t be able to find a solution to a thick a lining. However, if these all fail and, as a result, many transfers failed with because of insufficient endometrium lining, the last option would be a surrogate mother.

Is it all about the thickness? What else are you looking for?

Besides the thickness other factors related with the function of the endometrium are also important for the outcome, like: estimation of the receptivity window, immunological behaviour of the endometrium, Chronic Endometritis, colonization by pathologic microorganisms or imbalance of the natural flora, probiotic disorder, … all of them need to be checked out, especially if the patient already suffered from recurrent miscarriages or implantation failure.

Does the ER Map test help you see if the endometrium is ready?

Studies have shown that 70% of women find that 5.5 days of progesterone is the best time for embryo implantation. However, 30% need either one day more or less progesterone. Whether you are one of these women can be determined by the ER MAP testing. Through an endometrial biopsy at the end of a mock endometrial preparation cycle, we analyse the sample and we can adjust the protocol for the real cycle. We also check the immune response in the same sample to also rule out any abnormal immunological behaviour.

If you would like further information about this subject, or if you have any questions, drop us a line at info@ivfbabble.com