Scientists discover microplastics in SEMEN and female reproductive fluid - and warn they could spark an infertility crisis

From the depths of The Mariana Trench to the summit of Everest, microplastics can now be found almost everywhere on Earth.

Now, it turns out even our most intimate moments can't escape their blight.

Scientists have discovered microplastics are 'common' in both male and female reproductive fluids.

And they warned of the potential implications for reproduction, as egg and sperm quality could be impaired.

The team examined follicular fluid – found within the ovaries - from 29 women and the seminal fluid, found within semen, from 22 men.

Analysis revealed a range of commonly-used microplastics were present in more than half of the samples.

This included microplastics linked to non-stick coatings, polystyrene, plastic containers, wool, insulation and cushioning materials. 

Lead researcher Dr Emilio Gomez-Sanchez, from the University of Murcia, 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 per cent of the women and 55 per cent of the men we studied.'

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

While this research did not directly assess how microplastics affect fertility, their detection highlights the need to explore possible implications for human reproductive health, the researchers warned.

'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,' Dr Gomez-Sanchez added.

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

The scientists said the microplastics probably enter the body through ingestion, inhalation and contact with the skin.

From there they enter the bloodstream, which then distributes them throughout the body – including to the reproductive organs.

They plan to carry out further studies to explore the potential relationship between the presence of microplastics and egg and sperm quality.

The findings, published in the journal Human Reproduction, were presented at the annual meeting of the European Society of Human Reproduction and Embryology (ESHRE).

Commenting on the study 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 per cent 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.'

Previous studies have detected microplastics in human breast milk, blood and even brain tissue.

And separate research has found high levels in everyday items such as tea bags, baby bottles and chopping boards.

Some scientists have urged caution when interpreting the findings of the new study. 

Dr Stephanie Wright, Associate Professor in Environmental Toxicology at Imperial College London, said: 'Without information on the sizes of the microplastic particles observed, it is challenging to interpret how meaningful this data is. 

'There is a high potential for samples to become contaminated with microplastic throughout the sampling, laboratory processing, and analysis procedures. 

'It is not a surprise that microplastics have been found – they are everywhere, even in the lab – but the data provided do not support that they are there as a result of human exposure as opposed to methodological artefact and must be interpreted with caution at this early stage.'

Fay Couceiro, Professor of Environmental Pollution and Head of the Microplastics Research Group at the University of Portsmouth, said: 'The study is very interesting and considering the global reduction in fertility rates, looking at possible causes is very topical and timely. 

'As the authors state, finding microplastics is not that surprising as we have found them in lots of other areas of our bodies. 

'Presence is also not the same as impact and the authors are clear that while they have found microplastics in the reproductive fluids of both men and women, we still don't know how they are affecting us.'