Microplastics have now infiltrated nearly every corner of the planet, from the deepest reaches of the Mariana Trench to the summit of Mount Everest.
Now, it appears they may even be intruding on our most intimate biological processes.
A team of researchers has found that microplastics are “common” in the reproductive fluids of both men and women. They warned that these particles could compromise the quality of sperm and eggs, potentially impacting human fertility.
The scientists analyzed seminal fluid from 22 men and follicular fluid from the ovaries of 29 women. Their testing revealed that over half of these samples contained various types of microplastics, including those linked to wool, polystyrene, plastic packaging, non-stick coatings, insulation, and cushioning materials.
Dr. Emilio Gomez-Sanchez, the study’s lead researcher from the University of Murcia, explained:
“Previous studies had already shown that microplastics are present in multiple human organs. So while we weren’t entirely shocked to find them in human reproductive fluids, we were struck by just how widespread they were — appearing in 69% of women and 55% of men in our research.”
Microplastics, defined as plastic fragments smaller than 5 millimeters, have been shown to harm both the environment and public health. While this study did not directly examine their effect on fertility, the researchers emphasized that these findings highlight the urgent need to explore potential impacts on human reproductive health.
Dr. Gomez-Sanchez added:
“Animal studies show that microplastics accumulating in tissues can trigger inflammation, free radical production, DNA damage, cellular aging, and hormonal disruptions. It’s possible they might impair human egg or sperm quality, but at this point, we don’t have enough evidence to confirm that.”
According to the team, microplastics most likely enter the body through ingestion, inhalation, or skin contact. Once inside, they can travel through the bloodstream and reach various organs, including those involved in reproduction.
The researchers plan to carry out further studies to examine whether there is a link between microplastic contamination and egg or sperm quality. Their initial results were shared at the annual meeting of the European Society of Human Reproduction and Embryology (ESHRE) and published in the journal Human Reproduction.
Dr. Carlos Calhaz-Jorge, Immediate Past Chair of ESHRE, commented on the study:
“Environmental factors affecting reproduction are undoubtedly real, although measuring them objectively is difficult. The authors found microplastics in more than two-thirds of the follicular fluid samples and over half of the semen samples. Although the significance of these findings is still unclear, it should strengthen the case for reducing our daily use of plastics.”
Previous research has already detected microplastics in human breast milk, blood, and even brain tissue. They have also been found in everyday items like chopping boards, tea bags, and baby bottles.
Nevertheless, some scientists advised caution when interpreting these results.
Dr. Stephanie Wright, Associate Professor of Environmental Toxicology at Imperial College London, noted:
“Without details on the size of the microplastic particles detected, it is hard to gauge the significance of these findings. There is also a high chance that samples could become contaminated with microplastics during collection, lab processing, or analysis.”
“It’s not surprising to see microplastics — they are practically everywhere, including laboratories — but these data don’t conclusively prove that their presence is due to human exposure rather than contamination during testing, so we should interpret them carefully at this early stage.”
Fay Couceiro, a professor of environmental pollution and head of the Microplastics Research Group at the University of Portsmouth, added:
“This is a very timely and interesting study, especially given the global decline in fertility rates. As the authors point out, simply finding microplastics isn’t surprising since they’ve been detected in many parts of the human body. Presence, however, does not automatically equal impact, and while microplastics have been found in the reproductive fluids of both men and women, we still don’t know how — or even if — they affect us.”
