Tiny plastic particles in the fluids of human sperm and eggs

The human bloodstream is one of the surprising locations where tiny pieces of plastic, no larger than a human hair, have been found.

These fragments have now broken through the fluids surrounding eggs and are travelling with sperm, according to research presented at the meeting of the European Society of Human Reproduction and Embryology.

Under the direction of Dr. Emilio Gómez-Sánchez of Next Fertility Murcia in Spain, the research team scanned 22 men's seminal fluid and 29 women's follicular fluid.

In their study, the researchers discovered microplastics in 55% of the men and 69% of the women. Dr. Gómez-Sánchez stated that the team was taken aback by the particles' extensive distribution.

Human reproductive fluids containing plastics

Polymers like polytetrafluoroethylene and polypropylene, which are more commonly associated with food packaging and slick frying pans, were identified by the study. When they are observed near human eggs, a hypothetical risk becomes quantifiable.

In 2021, Italian obstetricians confirmed that particles smaller than five millimeters can breach the maternal-fetal border by finding twelve pieces of plastic in each placenta they investigated.

Similar-sized particles have been found deep into surgically removed lung tissue, demonstrating that inhalation is a practical way for plastic dust to be delivered.

In order to understand how pieces of plastic move to distant regions, researchers in the Netherlands have even analysed the quantity of plastic circulating in human blood samples.

How the body absorbs plastics

Because commonplace items release invisible dust when heated, abraded, or exposed to sunlight, the majority of people inhale plastic particles through their food, drink, or breath.

Particles that are tiny enough can pass through the intestinal wall or the lungs' thin air-blood membrane after being swallowed or breathed.

According to research on animals, pieces smaller than one micrometre can directly enter cells, while larger shards become stuck in tissue and cause local irritation. They avoid the body's normal waste filters in either case.

Because reproductive hormones travel on comparable lipid highways, research on fertility is affected by the fact that laboratory study on mice demonstrates that when microplastics hitch-hike on lipids, digestion intake increases. Concern is raised by the potential that plastics could serve as chemical transporters or endocrine mimics.

By collecting all human samples in glass vials and confirming that there was no background plastic present, Dr. Gómez-Sánchez's team was able to prevent laboratory contamination. This indicates that the polymers they discovered weren't just random lab dust but actually residents.

Plastic reduces fecundity.

Because oxidative stress overwhelms antioxidant defences, mice exposed to polystyrene shards shed sperm with damaged DNA and slow motility. After being exposed to nanoplastic, rodent Leydig cells exhibit shrivelled mitochondria, which reduces the amount of testosterone produced and causes litter sizes to decrease.

According to reviews published in 2024, microplastics can cause hormonal abnormalities and defective egg maturation by interfering with the hypothalamic-pituitary-gonadal axis.

Human oocytes take months to develop; thus, long-term exposure may be more significant than a brief surge. Because of this, the frequent finding of PTFE in sperm and eggs is particularly significant.

Levels of plastic in sperm and eggs

PTFE was found in 31% of the sampled egg fluid and 41% of the semen in the current data set. While polystyrene came in second among males and PP in second among women, polyethylene terephthalate was also present, albeit in smaller amounts.

According to the Minderoo-Monaco Commission on Plastics and Human Health, the amount of plastic produced annually has increased from less than two million tonnes in 1950 to around 460 million tonnes in 2019. This is a 230-fold increase.

The feedback loop between plastics and humans gets tighter with each rise in manufacturing since it leads to more litter, weathering, and fragment release. On the front line are reproductive cells, which are sensitive by nature.

According to Gómez-Sánchez, the majority of reproductive samples only had one or two plastic particles, which is regarded as small in comparison to the total amount of debris in the fluids. However, fertility experts point out that even trace metals can disrupt embryonic development; therefore, danger may not be predicted just by particle counts.

Plastics must be used in investigations on human fertility.

According to Professor Carlos Calhaz-Jorge of the University of Lisbon, "they should be viewed as an additional argument in favour of avoiding the generalised use of plastics in our daily lives." He added that more investigation is required to establish causation.

During in vitro fertilisation cycles, the research team will now examine hundreds of patients and correlate particle burdens with embryo quality. Beyond laboratory mice, those linkages may provide the first direct human evidence.

They design lifestyle surveys to determine whether behaviours like using a lot of bottled water or heating food in plastic are associated with increased particle counts. The method might turn abstract exposure theory into tailored guidance.

According to Dr. Gómez-Sánchez, microplastics are but one variable in a complicated equation. Instead of alarming people, he encourages moderation in the use of plastic.

Easy routines to reduce exposure

Because particles from container walls are no longer leached by heat or time, using glass or stainless steel bottles instead of plastic ones reduces ingestion. PTFE flakes can be reduced by swapping out scratched nonstick cookware.

Because knife motion releases shavings that stick to food, researchers recommend using ceramic or bamboo cutting boards instead of plastic ones. It also helps to let take-out cool before moving it from the styrofoam cartons.

Airborne fibres released by synthetic textiles are captured by air purifiers equipped with HEPA filters, which is particularly helpful in nurseries. Particles are prevented from resuspending by routine vacuuming with a sealed system.

Although these adjustments have drawbacks, such as eliminating chemical compounds that travel through plastic dust, they are not infallible. They buy time while the clinical stakes are sorted out by science.

Attempts to reduce pollution from human plastics

According to public health professionals, a supply system that produces over a billion pounds of new plastic every day cannot be outpaced by individual decisions.

United Nations negotiators are working on a global agreement that may limit production and simplify recycling.

Since reducing output is still the only reliable method of slowing the fallout of microplastics, Dr. Philip Landrigan of Boston College refers to the accord as a once-in-a-generation opportunity to safeguard human health. He cites new fertility figures as proof that there is not much time left.

Sharper imaging techniques and nanomechanical sensors are accelerating the science of sub-visible plastic, whether or not politicians take action. Studies that used to take months now complete in a matter of days, adding new hints to the literature.

The same picture becomes clearer with each new dataset: biological tissue has no secrets, plastics weather into dust, and dust spreads everywhere. It turns out that sperm and eggs are no different.