This study, conducted by the IVI Foundation and presented at the 39th Congress of the European Society of Human Reproduction and Embryology (ESHRE), analyzed the presence of non-essential trace elements in follicular fluid, plasma, and urine on both the day of ovarian puncture and embryo transfer. Thanks to this study, we now know that poorer IVF results can be motivated by high concentrations of these heavy metals.

Relationship between heavy metals and fertility 

Our daily reality is that one of the consequences of industrialization is the exposure to environmental pollutants to which we are subjected. This reality has negative consequences for our health, including fertility, caused by the years of our reproductive age that we spend exposed to these environmental factors. Specifically, this study has focused on heavy metals such as lead, mercury, or arsenic, as well as other less analyzed metals such as strontium, tin, cesium, and rubidium. The results indicate that higher levels of concentration of these elements – mercury in blood and strontium, tin, cesium, and rubidium in urine – are related to a lower ovarian response and poorer embryological results in IVF. On the other hand, a higher concentration of arsenic in the urine obtained on the day of transfer is associated with poorer results in the same assisted reproduction treatment.

“Without any doubt, 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”, explains Dr. Francisco Domínguez, researcher at the IVI Foundation and supervisor of the study.

How the study was conducted 

To carry out the study “Non-Essential Trace Elements in women’s biofluids are associated with worse IVF outcomes in euploid single embryo transfer cycles,” 51 women participated, with an average age of 39 years. Half of them were non-smokers and underwent an IVF treatment with the transfer of a single euploid embryo, meaning it had the correct number of chromosomes, in our clinics in Spain.

However, Dr. Domínguez emphasizes that in order to provide more conclusive results and recommendations, “these results are preliminary and need to be confirmed in a larger group of participants”. The goal is to understand the underlying mechanisms of these associations. “Not all individuals react the same way to exposure to these elements, and it is also necessary to correlate other variables associated with environmental and lifestyle factors”, concludes Dr. Domínguez.