The 39th edition of the European Society of Human Reproduction and Embryology (ESHRE) Congress took place from June 25th to 28th in Copenhagen. It is one of the leading global events in reproductive medicine, in which IVI once again had a prominent presence.
Topics such as the influence of environmental contaminants on fertility or the relevance of the endometrium are some of the main subjects that have focused the primary studies we share in this blog today. Find here Dr Diaz’s conclusions after ESHRE 2023:
Environmental contaminants and fertility
We now know that lifestyle is closely related to fertility. Specifically, Dr. Francisco Domínguez, a researcher at the IVI Foundation, has presented a study that shows that continuous exposure to environmental contaminants can be detrimental to conception.
Indeed, a higher concentration of non-essential trace elements such as mercury in the blood has been associated with a reduced ovarian response and poorer embryological outcomes in IVF. The same effect is observed with another group of less studied trace elements but present in the daily diet, such as strontium, tin, caesium, and rubidium in urine.
How do contaminants affect treatments?
In this context, the study reveals that higher concentrations of arsenic in the urine obtained on the day of embryo transfer significantly resulted in poorer clinical outcomes of in vitro fertilisation treatment.
This is how Dr. Domínguez explains it: “These results suggest a direct impact between the levels of non-essential trace elements and the outcomes of IVF treatment. It is still early to determine their exact source, but we can speculate that they could be associated with common components in our diet, such as mercury in fish, excessive rice consumption that can lead to arsenic levels, or the possible presence of strontium in cereals, leafy vegetables, and dairy products, for example. In addition to this, we need to consider our exposure to these non-essential traces in the environment.”
These results are still preliminary, as they were obtained from a sample of 51 women with an average age of 39, who underwent IVF treatment at IVI clinics in Spain.
IVI’s studies at ESHRE: the endometrium
The average age of first-time mothers is increasing throughout Europe. This has a negative impact on the quality of both oocytes and the embryos generated from them. This translates into difficulties in achieving implantation and a viable pregnancy, resulting in lower success rates in treatments.
In this context, research in reproductive medicine has been and continues to be focused on the study of embryos and improving their quality. However, the role of the endometrium should not be underestimated, as it is where implantation and the development of the future baby occur.
This is the origin of A gene expression risk signature of endometrial failure for prognosis in In Vitro Fertilization (IVF) patients, another study presented at the recently concluded ESHRE edition.
Dr. Patricia Díaz-Gimeno, a researcher at the IVI Foundation and supervisor of the study, explains: “The research we present in this scientific framework, for the first time, and thanks to transcriptomics combined with artificial intelligence algorithms, offers a new method with 95% accuracy in identifying genetic signatures that will help us distinguish between endometria with good and poor prognosis before initiating reproductive treatment.”
Establishing a prognosis for endometrial implantation
While displaced endometria outside the implantation window had been previously identified, it did not lead to a significant improvement in pregnancy rates. That’s why this new research provides added value by allowing the identification of endometria with good and poor prognoses. This, in turn, has led to a threefold difference in the risk of endometrial failure in patients with a poor prognosis. This can result in implantation failure or biochemical or clinical miscarriage.
Dr. Díaz-Gimeno warns that these are preliminary findings. “Further lines of study are still necessary for patients with poor prognosis endometria. However, being able to distinguish them preventively through the method we presented at ESHRE is the starting point for researching new procedures to improve their diagnosis and treatment. This will avoid the suffering of women and couples due to possible embryo loss, while improving the chances of success in their reproductive processes. These promising results are yet another example of our strong commitment to personalized or precision medicine,” concludes Dr. Díaz-Gimeno.
The dialogue between the endometrium and the embryo
In line with research focused on the behaviour of the endometrium, another relevant study has been presented, titled Extracellular vesicles secreted by the maternal endometrium functionally regulate processes related to embryo development and implantation in human blastocysts. A “dialogue” between the embryo and the endometrium based on vesicles has been identified. These vesicles are molecules secreted by the endometrium and captured by the embryo.
Dr. Hortensia Ferrero, a researcher at the IVI Foundation and supervisor of this study, explains: “The maternal endometrium secretes vesicles that are captured by human embryos. When the content of these vesicles enters the embryo, it regulates molecular mechanisms involved in improving embryonic quality and, consequently, their competence for implantation. These findings demonstrate the importance of the communication system between the maternal endometrium and the embryo through these small vesicles for successful implantation.”
Safer and more comfortable fertility treatments
Until now, it was believed that performing transfers during the patient’s natural cycle had limitations and resulted in an excessively rigid protocol. Although there have been previous studies that have attempted to delve into this point of the reproductive process, the truth is that their limitations and a small sample size have made it impossible to achieve the necessary certainties to advance in this direction.
Now, at IVI, we have presented a pioneering study, with a sample of over 3,000 embryos, called A new mNC protocol that allows a 7-day window for FET planning, led by Dr. Carlos Alonso, a gynecologist at IVI Madrid. He himself explains that the results are clear: “Embryo transfer can be scheduled if the endometrium is ready when the follicles measure between 13 and 20 millimeters, without altering the clinical outcomes of the process in any way.”
A natural cycle transfer requires minimal medication, making it more comfortable for the patient. Additionally, it improves efficacy and safety, reducing gestational risks such as preeclampsia towards the end of pregnancy. Dr. Alonso concludes, “These findings allow for nearly 7 days of flexibility in the modified natural cycle, which was previously unknown and is highly beneficial as it allows the timing of the transfer to accommodate the personal or work-related needs of the patients. Moreover, this flexibility is also advantageous for assisted reproduction clinics, as it enables fair organization and equitable planning of procedures.”