From my own studies as well as those of other researchers, it appeared that pinopodes are a reliable marker of endometrial receptivity. Pinopodes appear for only 2-3 days in the mid-secretory phase of the menstrual cycle. The exact cycle days that appear may vary from woman to woman. Examining the pinopodes in women with repeated failed embryo transfers, it appears that in several cases the window “opens” earlier or later than expected.Utilizing this information, the day of embryo transfer was accordingly modified with the aim of optimal embryo-endometrial synchronization, with good results. Following this concept of the personalized window of implantation, other methods of its calculation were later developed, with the molecular “ERA test” being the most prevalent.

This transfer day change has helped many women who had failed in previous attempts to become pregnant. However, there were many more that were not benefited from better embryo-endometrial synchronization. It was clear that something else was to blame for these failures; some factor other than timing was playing a much more decisive role. In recent years, improving the techniques of preparation and visualization of the samples I managed to see under the microscope something that left me astonished!

The vast majority of women with a history of repeated implantation failures and repeated miscarriages have inflammation and infection in the endometrium (chronic endometritis) which is often extensive and with intense damages. The cause and mode of onset of chronic endometritis is not clear. Abortions, childbirth, sexual activity and tampon use appear to be related. What is certain is that it is an “ascending” infection, that is, microbes that are in the vagina or cervix, somehow manage to penetrate the uterus and,ascending, can reach the fallopian tubes and block them.

Their chronic stay in the uterus is insidious as it does not give obvious symptoms or signs, but we can suspect it from the following features: dark period color, severe period pain (dysmenorrhea), pain during intercourse (dyspareunia), persistent vaginal infections, frequent urinary infections and of course infertility, either as inability to conceive or as loss of pregnancy in the form of spontaneous abortion.

Chronic endometritis is usually not seen in microbiological or histological tests, so it remains undiagnosed. Histologically, the diagnosis relies on complex immunohistochemical methods with low reliability. Microbiologically, taking a sample is problematic as it is done through organs that have germs,
i.e. the vagina and cervix, with a direct risk of contamination.

Ultrasensitive microbiological methods that detect molecules corresponding to microbes have recently been developed. Apart from the risk of contamination, the detection of these molecules does not imply the natural presence of the corresponding microbes in the endometrium, nor does it provide information on whether they cause damage and to what extent.
Therefore, these results, like the so-called “microbiome” of the uterus, have a rather theoretical value. With scanning electron microscopy chronic endometritis appears “alive” and in all its glory with numerous signs such as the presence of altered mucus and exudate, red and white blood cells, atrophy and degeneration of the tissue, hypertrophic cells and micropolyps and finally with the presence of microbes, often of different species. A quantitative assessment of the extent of the damage is made and any other accompanying alterations are also identified, e.g. those due to hormonal disorders.

The Nikas Test has high reliability, sensitivity and specificity far beyond other when it comes to the diagnosis of endometrial inflammations/infections and of course the evaluation of the therapeutic effect. In addition, with the same examination the window of implantation can be estimated.