Microplastics present in human reproductive fluids

Data presented at ESHRE 2025 indicate the presence of microplastics (MPs) in follicular and seminal fluids, underscoring concerns about their potential impact on reproductive health.

“MPs are probably the most dangerous plastic waste,” said lead investigator Dr Emilio Gomez-Sanchez from Next Fertility Murcia, Spain, at ESHRE 2025. MPs are plastic particles between 5 mm and 1 µm.

Using laser direct infrared imaging, the MPs identified in the reproductive fluid samples include polytetrafluoroethylene (PTFE; commonly known as teflon), polyethylene terephthalate (PET), polyamide (PA), polyethylene (PE), polyurethane (PU), polypropylene (PP), and polystyrene (PS).

Sixty-nine percent of the follicular fluid samples obtained from 29 women contained MPs, with PTFE being the most abundant (31 percent), followed by PP (28 percent) and PET (17 percent). Smaller amounts of PA, PE, PU, and PS were detected (14, 10, 10, and 7 percent, respectively). [ESHRE 2025, abstract O-280]

MPs were also found in 55 percent of the seminal fluid samples obtained from 22 men. Again, PTFE emerged as the most prevalent polymer (41 percent). Lower concentrations of PS, PET, PA, and PU were found (14, 9, 5, and 5 percent, respectively). “It remains to be clarified whether these came from the seminal glands, the epididymis, or the testicles,” noted Gomez-Sanchez.

The higher concentration of MPs in the ovaries compared to that found in semen may be due to enhanced vascularization during ovarian stimulation, he added.

MPs were mostly rounded particles, comprising about two-thirds of both male and female fluid samples. About a quarter were irregular particles. Small amounts of thin and coarse fibres were detected (about 4–8 percent). Sizes ranged between 50 and 150 µm.

“Previous studies had already shown that MPs can be found in various human organs. Hence, we weren’t entirely surprised to find MPs in [human reproductive fluids], but we were struck by how common they were,” noted Gomez-Sanchez in the press release.

A threat to reproductive health?

Although the study did not directly evaluate the effects of MPs on fertility, their presence in reproductive fluids highlights the need to explore possible implications for human reproductive health.

“What we know from animal studies is that MPs can induce inflammation, free radical formation, DNA damage, cellular senescence, and endocrine disruptions in the tissues where they accumulate,” Gomez-Sanchez noted. “It’s possible that they could impair egg or sperm quality in humans, but we do not have enough evidence yet to confirm that.”

For those trying to conceive, Gomez-Sanchez underlined that “there’s no need for alarm at this point. MPs are just one of the many elements that may [influence] fertility. However, it is sensible to consider ways of reducing our exposure to them.”

Simple steps, such as using glass containers for food storage or limiting water consumption from plastic bottles, can help minimize intake, he said. In the study, all samples were collected and stored in sterile glass containers to prevent plastic contamination.

May be a valid reason to avoid plastics

Despite the promising findings, Gomez-Sanchez noted that these should be interpreted with caution, given the limited sample size. The team intends to expand their analysis to larger cohorts to reinforce these preliminary findings, evaluate the potential associations between patient parameters and MPs, and ascertain the impact of MPs on reproductive health.

“Environmental factors influencing reproduction are certainly a reality, although not easy to measure objectively … Although the significance of these findings is not yet clear, they should be considered an additional argument in favour of avoiding the generalized use of plastics in our daily lives,” commented Immediate Past Chair of ESHRE Professor Dr Carlos Calhaz-Jorge from Universidade de Lisboa, Portugal.