Microplastics Invade Human Eggs and Sperm

Emerging research links ubiquitous plastic particles to potential fertility risks.

Alarming new data reveals microplastics, minute plastic fragments smaller than a human hair, have infiltrated human reproductive fluids. This raises concerns about potential impacts on fertility and overall health, prompting calls for further research and reduced plastic use.

Plastics Found in Reproductive Systems

Research presented at the European Society of Human Reproduction and Embryology meeting indicates these microplastics are present in follicular fluid surrounding eggs, and also within human sperm. The study, spearheaded by Dr. Emilio Gómez‑Sánchez from Next Fertility Murcia in Spain, examined follicular fluid from 29 women and semen samples from 22 men.

The results showed microplastics in 69% of the female samples and 55% of the male samples. Dr. Gómez‑Sánchez expressed surprise at the widespread presence of these particles. The investigation identified polymers like polytetrafluoroethylene (Teflon) and polypropylene, commonly found in non-stick cookware and food packaging.

In fact, the U.S. Geological Survey found microplastics in 100% of water samples taken across the country, including in bottled water (USGS 2024).

Prior Research Highlights Plastic’s Reach

In 2021, Italian obstetricians discovered plastic fragments within placentas, demonstrating the ability of these particles to cross the maternal‑fetal barrier. Similarly sized particles have been found in lung tissue, confirming inhalation as another route of exposure. Researchers in the Netherlands have even detected plastic mass circulating in human blood, explaining how these fragments reach distant tissues.

How Microplastics Enter the Body

Exposure to these plastic particles primarily occurs through ingestion, inhalation, and drinking, as everyday products shed plastic dust. Once inside the body, these particles can penetrate the gut wall or the air-blood membrane in the lungs. Smaller particles can enter cells directly, while larger ones can become trapped in tissues, causing irritation.

Fertility Concerns

Animal studies suggest that microplastics can negatively impact fertility. Mice exposed to polystyrene exhibited sperm damage and reduced movement, linked to oxidative stress. Additional research on rodent Leydig cells revealed shrunken mitochondria after nanoplastic exposure, reducing testosterone production. Reviews from 2024 indicate microplastics may disrupt the hypothalamic‑pituitary‑gonadal axis, leading to hormonal imbalances and impaired egg maturation.

Dr. Gómez‑Sánchez’s team took precautions to avoid laboratory contamination, confirming that the detected polymers were genuine residents within the samples. Of the samples, PTFE was found in 31% of egg fluid samples and 41% of semen samples. Polypropylene was the second most prevalent among women, while polystyrene was second among men.

The Growing Plastic Problem

Annual plastic production has surged dramatically, from under two million tons in 1950 to approximately 460 million in 2019, according to the Minderoo‑Monaco Commission on Plastics and Human Health. Increased production leads to more litter and fragment release, intensifying the connection between plastics and human exposure. Gómez‑Sánchez noted that most reproductive samples contained only a few plastic particles, but fertility specialists caution that even trace amounts of certain substances can disrupt embryo development.

Expert Recommendations

“They should be considered an additional argument in favor of avoiding the generalized use of plastics in our daily lives,” stated Professor Carlos Calhaz‑Jorge of the University of Lisbon. He also emphasized the need for further research to establish causation.

The research team plans to study hundreds of patients, linking particle loads to embryo quality during in vitro fertilization cycles. Lifestyle questionnaires will assess whether habits like bottled water consumption or microwaving food in plastic correlate with higher particle counts. Dr. Gómez‑Sánchez urges moderation in plastic use, emphasizing that “Microplastics are just one variable in a complex equation.”

Reducing Exposure

To lower exposure, switching to glass or stainless-steel bottles and replacing scratched nonstick pans are recommended. Avoiding plastic cutting boards, cooling take‑out food before transferring it from polystyrene containers, and using air purifiers with HEPA filters can also help.

Call for Systemic Change

Public‑health researchers argue that individual actions alone are insufficient to address the scale of plastic pollution. Dr. Philip Landrigan of Boston College calls the UN treaty a “once‑in‑a‑generation chance to protect human health,” emphasizing that curbing plastic production is crucial to slowing microplastic fallout. The emerging fertility data underscores the urgency of this issue.

With advancements in imaging tools and sensors, the science of microplastics is rapidly evolving, providing fresh insights into their impact on human health.