Microplastics have been found in male and female reproductive fluids, in the latest horrifying evidence of their ability to penetrate deep into the human body. Scientists tested follicular fluid from 29 women and seminal fluid from 22 men. Follicular fluid is a liquid found within ovarian follicles, a fluid-filled sac in the ovary that contains an immature egg.

Microplastics were found in 68% of follicular fluid samples and 55% of seminal fluid samples. Study leader Dr Emilio Gomez-Sanchez said: "Previous studies had already shown that microplastics can be found in various human organs. As a result, we weren't entirely surprised to find microplastics in fluids of the human reproductive system, but we were struck by how common they were - found in 69% of the women and 55% of the men we studied."

Analysis using laser directed infrared microscopy identified a range of commonly used microplastic polymers including polytetrafluoroethylene (PTFE), polystyrene (PS), polyethylene terephthalate (PET), polyamide (PA), polypropylene (PP) and polyurethane (PU).

Microplastics are defined as plastic particles under 5mm in size, and there is evidence that they pose a threat to environmental and public health.

Researchers said the study did not directly assess the impact of migropladtics on fertility, but this should be explored. The team is now planning further work looking at the potential relationship between microplastics and

Dr Gomex-Sanchez added: "What we know from animal studies is that in the tissues where microplastics accumulate, they can induce inflammation, free radical formation, DNA damage, cellular senescence, and endocrine disruptions.

"It's possible they could impair egg or sperm quality in humans, but we don't yet have enough evidence to confirm that."

The research team plans to expand their analysis to a larger cohort, alongside detailed lifestyle and environmental exposure questionnaires.

Further phases of the project will also explore the potential relationship between the presence of microplastics and ovary cell and sperm quality.

Fertility is influenced by many factors including age, health, and genetics, and that the findings should not alarm those trying to conceive, Dr Gomez-Sanchez added.

He said: "There's no need for alarm at this point. Microplastics are just one of many elements that may play a role in fertility.

"However, it is sensible to consider ways of reducing our exposure to them. Simple steps, such as using glass containers to store and heat food, or limiting the amount of water we consume from plastic bottles, can help minimise our intake."

The findings were presented at the European Society of Human Reproduction and Embryology's 41st annual meeting.

Professor Dr Carlos Calhaz-Jorge, immediate past chair of ESHRE, said: "Environmental factors influencing reproduction are certainly a reality, although not easy to measure objectively.

"The authors of this study found microplastics in over two-thirds of follicular fluids and more than 50% of semen fluids from the studied patients.

"Although the significance of these findings is not yet clear, they should be considered an additional argument in favour of avoiding the generalised use of plastics in our daily lives."

The study abstract was published in Human Reproduction, one of the world's leading reproductive medicine journals.