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“Nadezhda” with Another Successful Presence at ASRM
“Nadezhda” was part of the scientific program of the world’s largest reproductive medicine congress in the United States. Our team submitted eight scientific abstracts — all of them were accepted and presented there.
08.12.2025 | 09:28
At the end of October, in San Antonio, one of the largest reproductive medicine congresses in the world took place — the annual meeting of ASRM.
We are proud that, for another consecutive year, Nadezhda Hospital was part of this prestigious event. Our team participated in the scientific program with eight research projects presented as posters.
To tell us more about the congress and what we presented there, we spoke with Dimitar Parvanov, Head of the Research Center at Nadezhda Hospital.
He has been part of our research laboratory team since 2013. He completed his higher education at the Faculty of Biology at Sofia University in 2004 and defended his doctoral dissertation in 2009. His scientific interests are in reproductive medicine and biostatistics.
1. What does the ASRM congress represent for the global reproductive community?
ASRM (American Society for Reproductive Medicine) is the largest professional organization in the United States dedicated to reproductive medicine and biology. Every year, it organizes an international congress attended by more than 10,000 delegates from around the world. Together with the European congress of ESHRE, it is the most significant event in our field.
This year, the 81st edition of the congress took place from October 26 to 29 in San Antonio, Texas, and was accompanied by the celebration of the 75th anniversary of the journal Fertility and Sterility — one of the most prestigious publications in the field. Our own publications have also been included in its issues, which is a great honor and recognition.
2. What was the level of interest in the event?
Interest in the ASRM congress is traditionally very high. Participants come from the United States, Europe, Asia, South America — practically from all over the world. This year as well, “Nadezhda” was the only representative from Bulgaria, and not merely as attendees, but as part of the scientific program.
To be accepted into the program requires going through a rigorous selection process, as thousands of abstracts are submitted each year, and only a relatively small number are approved. Our team applied with eight abstracts, and all were accepted. This gave us the opportunity to present our work in poster format during the two main days of the event.
On-site, I was accompanied by my colleague Lachezar Zhelezarski, a biologist in the Research Laboratory. In addition to presenting our data, we had the chance to explore the latest innovations in various areas of reproductive medicine showcased at the congress.
3. How many times has the “Nadezhda” team participated in ASRM?
Nadezhda Hospital has participated in ASRM since its founding. Even before the hospital itself was established, the IVF center team had already taken part in this forum.
Over the years, the number of our accepted scientific works — both posters and presentations — has increased. It is an event that provides a unique opportunity for knowledge exchange, new ideas, and a real assessment of how far we have progressed compared to leading centers worldwide.
4. What did you present to the congress delegates this year?
The topics we presented this year were primarily focused on the immunology of reproduction. Part of our work examined how the immune status of the uterus changes under different conditions — inflammation, previous surgeries, or medical procedures — and how important it is to monitor these factors before an IVF procedure in order to select the most appropriate treatment and timing for embryo transfer.
Another topic explored not only the quantity but also the spatial distribution of certain cell types in the endometrium. This included immune cells as well as so-called “zombie cells” — cells that no longer function normally. We found that in patients with repeated implantation failures, these zombie cells are located too far from key immune cells such as T-helper and NK cells. This disrupts their normal interaction and negatively affects endometrial receptivity.
A significant part of our research was also dedicated to what happens after miscarriages — both in the uterus and in peripheral blood. We observed that with each pregnancy loss, certain immune memory cells increase and may remain in the body for years. This is a normal protective mechanism, but in subsequent pregnancies, these cells can become overly active and perceive the embryo as a threat.
We also established that as the number of previous losses increases, so does the proportion of zombie cells that release substances sustaining inflammation. This creates a less favorable environment for conception and pregnancy maintenance. Our work in this area aims to identify biomarkers that can help us understand when there is an elevated risk of miscarriage and determine whether a given treatment is effective even before an IVF procedure begins.
This is extremely important because in many cases, one should not rely solely on the final result — whether the pregnancy succeeds or not. It is far more useful to monitor how the immune system responds during the preparation stage.
We also presented results from our cell-based therapies — models built from specific immune cells that can support endometrial receptivity. This is a field in which we are actively working because it offers the possibility of personalized treatment based on the cellular characteristics of each individual patient.
Two of our posters were linked to our joint work with the Institute of Biology and Immunology of Reproduction at the Bulgarian Academy of Sciences and the team led by Associate Professor Dr. Tanya Dimova. Together, we are developing an embryoid model — a structure created from stem cells that resembles an early embryo, combined with a monolayer of endometrial cells.
We monitor whether the embryoid cells “migrate” toward the endometrial cells, which allows us to evaluate whether a patient’s endometrium is receptive. This model makes it possible to pre-test different therapies and select the most appropriate treatment for each patient.
The interest in our topics was substantial. We had the opportunity to discuss our studies with PhD candidates, scientists, specialists from various organizations, and representatives of scientific journals.
It was a great honor that one of our posters was selected for the Top Poster Session of the congress.
5. What lies ahead for the Research Center?
Everything we do — both our current work and future projects — is possible because at Nadezhda Hospital we function exceptionally well as one united team. Our studies and scientific ideas are not the work of a single laboratory, but of the combined efforts of our clinical practice, andrology, embryology, pathology, genetics, immunology, microbiology, and virology laboratories. We also work daily with physicians led by Dr. Stamenov, as well as with midwives and nurses from the hospital wards. This collaboration between departments allows us to address problems comprehensively, connect clinical cases with laboratory findings, and create new diagnostic and therapeutic approaches that otherwise would not be possible.
So far in 2025, we have published more than ten scientific papers in prestigious journals, and by the end of the year we expect at least five more. For a team of eight people who, in addition to scientific work, also perform routine laboratory activities, this is an exceptional achievement.
In 2026, we hope that projects related to in vitro implantation models will be approved. We aim to further develop the embryoid model, validate new biomarkers for implantation failure and recurrent miscarriage, and refine cell-based therapies such as platelet-rich plasma (PRP) and peripheral blood mononuclear cells (PBMC).
Our goal is to produce even higher-quality publications and strengthen our position on the international scientific stage. Most importantly, however, we aim to provide more precise diagnostics and more successful treatment outcomes for our patients.
