Is our plastic addiction the cause of the modern fertility crisis?

Modern societies have become addicted to plastic. Around 130 million tons are produced each year — generating approximately twice as much waste as two decades ago, according to the OECD.

A 2021 study by Minderoo found that the average American buys and throws away 110 pounds (50kg) of plastic annually.

Despite environmental awareness, just 15% of plastic waste is collected for recycling, and only 9% is actually recycled, according to the OECD.

The rest ends up in uncontrolled dumpsites, is burned into the air, ends up polluting the land, water or even living creatures.

Although plastic has only existed for 60-70 years, it can be found in every corner of the globe. That’s because it can take hundreds of years to break down, if it does at all, according to the WWF.

When plastic does decompose, it breaks down into tiny little pieces called micro or nano plastics and can release hazardous chemicals into the environment.

A study by the University of Newcastle found that the average person may be eating, drinking and breathing in up to five grams of plastic per week — the equivalent to a credit card.

The health implications of consuming so much plastic are still being studied, but scientists warn it could have an impact on our health and that of future generations.

The average sperm count in Western men has been halved over the last 40 years. Dr Shanna Swan, Professor of Environmental Medicine and Public Health at Mount Sinai school of medicine in New York, says plastic is likely a significant factor behind that decline.

A 2022 European study found that men have “astonishing levels,” up to 100 times more than considered safe, of a cocktail of chemicals in their bodies. Bisphenol A (BPA), found in plastic, was responsible for the highest risk and is the most worrying chemical.

Sperm count isn’t the only determinant of fertility; semen quality matters too. The same European study found that this common chemical cocktail was linked to poor semen quality in 100 Danish men. BPA was the biggest driver of risk, followed by dioxins (released in the air when waste is burnt), paracetamol (like Tylenol) and phthalates (also from plastics).

Dr Swan says one of the biggest dangers to male fertility are phthalates, chemicals added to plastics to make them more flexible. They are particularly risky because they've been shown to lower testosterone.

The Mount Sinai epidemiologist says there is a direct link between phthalate exposure in the womb and fertility issues in men. When pregnant women are exposed to certain chemicals commonly found in plastic, like phthalates, it can decrease the distance from the anus to the genitalia in male offspring, which is correlated with low sperm counts.

Rodents exposed to microplastics had worse sperm quality as a consequence of the inflammation and oxidative stress damage it caused, according to a study published in the International Journal of Environmental Research and Public Health. “The possible reproductive health risks of microplastics should not be ignored,” the study warned.

Studies indicate that women with fertility problems have higher levels of bisphenol A (BPA), commonly found in plastic drinks bottles, canned food linings and cash-register receipts. Dr Swan says it’s particularly bad for women because it mimics estrogen in the body.

After adjusting for maternal characteristics like age, the rate of miscarriage increased by 1% per year in the US between 1990 and 2011, according to one scientific study. This can be influenced by both female and male factors, and the authors concluded that more studies are needed to figure out why.

Even for women who can get pregnant and avoid a miscarriage, pregnant women exposed to multiple phthalates during pregnancy had an increased risk of preterm birth, according to a 2022 National Institutes of Health study.

Based on current fertility trends, which show no signs of improvement, Dr. Swan predicts that most couples will need assisted reproduction to conceive within little more than the next twenty years. While she doesn’t claim that’s all due to plastics and related chemicals, she suggests society's plastic addiction is a leading factor.

While plastic is almost everywhere, experts say exposure can be reduced by eating unprocessed foods, not cooking with Teflon and avoiding heating or microwaving plastic. Cosmetic products can also contain phthalates, most commonly to hold fragrance.

Dr Swan says these chemicals are being eliminated, but new, unstudied ones, are popping up all the time. “If it says “BPA free” it probably doesn’t have BPA. But notice that it doesn’t say bisphenol free so you could still be getting bisphenol S or F, which are regrettable substitutes. “Phthalate free” I would also be suspicious of. While it might be free of the old, well-known actors, it may not be free of newer ones,” she told the Guardian.

Never in history have there been more humans on planet earth. Still, over the last 50 years, there has been a “severe decline in childbirth which will lead to population declines, particularly in industrialized regions,” according to a 2021 Nature paper. Data shows that human reproductive health is deteriorating in industrialized regions, with more reliance on treatments like IVF.

Photo: Humphrey Muleba/Unsplash

While the evidence is growing that plastic could be affecting fertility, it is still not 100% conclusive. Other hypotheses point to older maternal age and socioeconomic factors like expensive housing, birth control and female employment conditions for the decline in birthrates. Other environmental factors like fertilizers and lifestyle issues like obesity and smoking are also believed to play roles.