Infertility rates are rising worldwide. According to the World Health Organisation, one in four couples fail to conceive after one year of unprotected sex. In Ireland, one in six couples experiences infertility.
For decades, we have pointed the finger at women playing Russian roulette with their biological clocks by delaying starting a family until their careers are established. But, while this is a significant contributing factor, men’s declining fertility is now recognised as playing an equally important role.
Emerging research suggests some of the chemicals we use in everyday life disrupt fertility, male fertility in particular.
A disturbing new book outlines the research showing links between these chemicals and a dramatic decline in sperm counts. Its author, Professor Shanna Swan, predicts most couples will have to resort to IVF by 2050 if this decline continues.
Swan is a high-profile professor of environmental medicine and public health at Mount Sinai School of Medicine in New York, where she has studied fertility trends for some 30 years.
Her book ‘Countdown: How our modern world is threatening sperm counts, altering male and female reproductive development, and imperilling the future of the human race’ grew out of an alarming study she published in 2017. Her research, which made international headlines, found that the concentration of sperm in men’s ejaculate had fallen by an average of 1.4% worldwide between 1973 and 2011.
“That’s an overall decline of 52% and it shows no sign of tapering off,” Swan tells. “If it continues at this rate, the human race will be unable to reproduce itself and by 2050, many couples will have to turn to technology.”
Her book examines what might be causing this decline and other related fertility issues. “There are many factors, including delayed childbearing and lifestyle issues,” she writes. “Chemicals in our environment are a major one. The worst offenders are endocrine-disrupting chemicals (EDCs).
Found in everyday substances from paint to pesticides, they interfere with our body’s natural hormones and play havoc with the building blocks of sexual and reproductive development.”
Oestrogen and testosterone are the two main hormones that influence our reproductive systems. EDCs can interfere with or mimic these hormones, fooling the body into thinking it has sufficient levels of them to stop its own production. This then impacts reproductive development, fertility, and health.
Professor Swan isn’t the only academic worried about EDCs. Lisa Connolly is a professor at the Institute for Global Food Security in Queen’s University Belfast. She coordinates the EU PROTECTED Project, which carries out research into the threat to public health from EDCs. She is also organising the first international endocrine disruptor conference to take place in Ireland from June 15 to 16.
“EDCs are a huge concern,” says Connolly. “Both male and female fertility rely on a healthy hormone system, so chemicals which disrupt hormones can have detrimental effects on the development of healthy male sperm and female eggs.”
She cites a report on the effects of endocrine disruptors on human health issued by the WHO and UN in 2012 as a pivotal publication in this field. It found that up to 40% of young men in some countries had low semen quality, which reduced their ability to have children.
It also stated that “close to 800 chemicals - are known or suspected of being capable of interfering with hormones. However, only a fraction has been investigated in tests capable of identifying overt endocrine effects in intact organisms. The vast majority of these chemicals in current commercial use have not been tested at all.”
Mindy O’Brien is the coordinator of the environmental charity Voice of Irish Concern for the Environment. The charity is currently part of the Break Free from Plastic taskforce set up by Chem Trust, a European organisation aiming to prevent man-made chemicals from causing long-term damage to wildlife or humans.
“We follow a precautionary principle,” says O’Brien. “If we don’t know the impact of these chemicals, we shouldn’t be releasing them into our environment.”
Yet these chemicals are found in a vast array of everyday items. “Bisphenols and phthalates are used in plastic production to make bottles, food packaging, and children’s toys,” says Connolly.
“Cosmetic products contain preservatives called parabens and antimicrobials such as triclosan. Electrical goods and household materials often contain flame retardants such as polybrominated diphenyl ethers (PBDEs) and non-stick cookware, paper and textile protectors can contain chemicals called perfluoroalkyl and polyfluoroalkyl substances (PFASs).”
We touch these chemicals. We breathe them in. We even eat some of them as a result of phthalates and bisphenols leaching into food from packaging, or crops being sprayed with pesticides. “We are exposed to a cocktail that bioaccumulates in our bodies over time,” says Connolly.
Research carried out by the HSE in 2017 proves just how pervasive these chemicals are. Some 120 mother-child pairs from all over the country were tested for phthalates and all were found to have been exposed to them.
Because phthalates and bisphenols are used in packaging, they are a particular concern of O’Brien’s. “As these chemicals age, they break down and contaminate our food,” she says. “This means that small trace amounts can be found in so much of what we eat and yet they are largely unregulated and research into them is ongoing.”
Swan’s book outlines some of this research, which proves the harm phthalates can do. They lower testosterone, which means they have the strongest effect on males, diminishing their sperm count.
Exposure to phthalates is most harmful in utero. “Our bodies undergo sensitive development at this time which is controlled by hormones,” says Connolly. “If this delicate process is disrupted, the effects can be serious.”
The right amount of testosterone at the right time ensures the normal development of a male foetus’s reproductive system. “Any influence that changes productions of key hormones during this time can lead to low sperm count and shorter ano-genital distance (AGD),” says Swan.
AGD is a key indicator of fertility. Studies she carried out between 1999 and 2009 looked at AGD, which is the distance from the anus to the genitals.
“It indicates how much male sex hormones including testosterone an infant is exposed to in early pregnancy,” writes Swan. “We now know it’s an important marker of reproductive health and endocrine disruption, which shorter AGDs in males and longer AGDs in females indicating less reproductive success.”
This research started with studies of rats in the 1990s. Females given phthalates had male babies with lower sperm counts and shorter AGDs.
Swan followed this with a 2005 study that tested pregnant women’s urine for phthalates and measured their male babies’ AGDs. Mothers with higher levels of phthalates in their urine had babies with shorter AGDs.
She then carried out a study of college-age men, who gave semen samples and had their AGDs measured. “The shorter the AGD, the lower the sperm count,” says Swan. “We had a direct link from phthalates to short AGD and from short AGD to low sperm count.”
EDCs don’t just affect male reproduction. “They are bad for women too,” says Swan. “They’ve been shown to decrease libido and increase the risk of early puberty, premature ovarian failure, miscarriage, and premature birth.”
Another of Swan’s studies looked at the EDC Bisphenol A. Women with the highest levels of this in their blood were shown to have an 83% higher risk of miscarriage in their first trimester.
Miscarriage rates may even be increasing across the board. They certainly are in the US where a 2018 study by the Centres for Disease Control and Prevention found that rates had increased by 1% a year between 1970 and 2000.
Both Swan and Connolly draw a link to our growing exposure to EDCs and risk of miscarriage. “These chemicals are associated with an increased risk of miscarriage,” says Connolly. “This is because foetal development and tissue are much more sensitive to chemicals.”
While Irish fertility clinics do not monitor these changes in fertility rates, they are aware of the trends. “We see patients every week who have no sperm in their ejaculate and more again who have low sperm count,” says Dr Tim Dineen, a Cork-based senior clinical embryologist, and a founding member of the Waterstone Fertility Clinic.
Couples are often surprised to hear infertility can be associated with the male partner. “They don’t realise that as many fertility issues stem from the male as the female,” says Dr Dineen.
“About a third of fertility issues lie with the male partner, a third with the female and a third are attributed to a combination of both. About 7% of men in the general population have fertility issues. It’s a common condition.”
He advises men and women to look after their fertility. “Keep it in mind,” he says. “Make it part of your decision making and make good choices in order to protect it.”
For decades, those choices have included avoiding smoking, maintaining a healthy weight and level of exercise, improving your nutrition, and getting good sleep. Now it seems we need to add avoiding EDCs.
“Endocrine-disrupting hormones are found in many everyday items that we come into contact with on a frequent basis, such as our food and water, shampoos, soaps, and cosmetics,” says Dr Dineen. “They interfere with the synthesis or action of these hormones, which can result in abnormal reproductive functions, including a decline in semen quality.”
If we’re trying to avoid them, Swan urges us to start in our kitchens. “Food is the greatest source of exposure to these chemicals,” she says. “Replace plastic containers with glass and ceramics. Never microwave in plastic, and when possible, eat unprocessed food.” (See sidebar for more tips.)
O’Brien agrees. “Buy package-free food if you can,” she says. “If you can’t, decant food from plastic packaging as soon as you get home.”
Connolly believes the onus is on regulators to protect the public from EDCs. “All new chemicals ought to be tested for safety prior to use,” she says. “Currently, we tend to only find out a chemical is dangerous after we see its devastating effects on health – as we are now seeing with declining sperm counts in men.”
But Swan is heartened by work being done by the EU Commission. “The development of their chemicals strategy for sustainability towards a toxin-free environment is hopeful,” she says.
This work resulted in three of the worst phthalates (di-2-ethylhexyl phthalate, dibutyl phthalate, and butyl benzyl phthalate) being banned in 2015. If all EDCs were banned in this way, Swan believes their effects could be reversed.
“Many of these chemicals are nonpersistent, which means they are water soluble and leave our bodies within days,” she says. “If we banned them and ceased production, we could recover our reproductive health and function within three generations.”
She hopes her book will inspire people to call for such a ban. “I am cautiously optimistic my message will be heard, people will realise the extent of the problem, and this will lead to changes that reverse the damage and threats to our health and survival.”
Endocrine-disrupting chemicals are taking a toll on male and female fertility and will continue to do so for generations unless we do something to stop them. Regulation will inevitably take time. What can we do on a personal level right now?
Here’s some advice from the Endocrine Society, a global community of doctors and scientists working in the field of hormonal health and from Professor Shanna Swan.
- 1. Take care when buying food. Buy as much fresh, unprocessed food as possible to minimise plastic packaging.
- 2. Pay attention to how you store food. Phthalates and Bisphenol A are used in many plastic containers and bottles. Glass, metal, or ceramic containers are a better option.
- 3. Avoid microwaving or heating food in plastic containers. EDCs can seep into food when heated.
- 4. Consider how you prepare your food. Non-stick pans are often made with EDCs, which can taint your food. The next time you buy pans, choose stainless steel or cast iron ones instead.
- 5. Dr Swan recommends going through your cleaning products and dumping any that feature words like danger, poison, or fatal on the label. Make your own with household staples like vinegar or baking soda.
- 6. Read the label when choosing cosmetics such as shampoos, conditioners, cleansers, moisturisers, sunscreens, makeup, and toothpaste. Try to ones that are paraben and phthalate free. Key chemicals to avoid include triclosan, dibutyl phthalate (DBP) and parabens such as methyl-, ethyl-, propyl-, isopropyl, butyl-, and isobutyl-.
- 7. Avoid fragrant products as they often contain phthalates. Choose fragrance-free creams, cleaning products, and laundry detergents and if you need to freshen your indoor air, try an open box of baking soda that absorbs odours.
- 8. Replace plastic bags with cloth or canvas ones that are washed regularly and clingfilm with a beeswax-coated cloth.
- 9. Buy phthalate-free and PVC-free toys when possible and choose baby bottles and beakers that don’t contain bisphenol A (BPA).
- 10. Lobby companies, agencies, and policymakers to change laws and policies concerning EDCs so that they are not introduced to our food or our homes in the first place.