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January 12, 2024 Big Chemical News

Big Chemical

‘Remarkable’ Declines in Fertility, Sperm Counts Worldwide Linked to Industrial Chemicals

Fertility rates are dropping persistently worldwide, with environmental toxins like pesticides and air pollution likely playing a key role, according to a study published in Human Reproduction Update. Health experts urged policy action on chemical exposures and barriers to fertility care.

decline fertility air pollution feature

By Shannon Kelleher

Health researchers from around the world are sounding an alarm on a persistent drop in fertility rates, pointing to environmental pollutants among a wide range of factors that they argue need to be urgently addressed in a paper published Wednesday.

Both male and female reproductive health is deteriorating, especially in industrialized regions, suggesting important roles of environmental factors, such as endocrine-disrupting chemicals and pesticides, the authors of the paper state.

Studies indicate that the global fertility rate is dropping, with 93% of all countries worldwide expected to dip below levels necessary to keep populations from shrinking by 2100.

The trend is driven, in part, by the impacts of exposure to toxic chemicals, as well as lifestyle factors such as smoking and obesity, according to the 11 researchers authoring the paper, which was published in the journal Human Reproduction Update.

The researchers — who come from multiple countries, including the U.S., Australia, South Africa, Greece and Denmark — reviewed dozens of studies in coming to their central conclusion that public policy, research and medical access must be stronger on the topic of fertility.

In conjunction with the publication of the paper, the International Federation of Fertility Societies (IFFS), which represents fertility societies in 65 countries, launched a global campaign on Wednesday seeking to push policymakers to make fertility care more affordable, accessible and equitable, and to adopt policies that aid fertility, including reducing exposures to air pollution and other harmful chemicals linked to reproductive harm.

The paper says that “due to multiple societal and environmental changes, it is important to emphasize that globally between 48 million couples and 186 million individuals of reproductive age live with infertility.”

They call infertility “a common chronic disease affecting many reproductive-age women and men.”

Data on the decline in total fertility rate around the world — the number of children each woman gives birth to, a critical factor in population growth — is “pretty remarkable,” said Tracey Woodruff, a professor at the University of California, San Francisco School of Medicine who was not involved in the paper.

“This is really an important issue because it impinges on people’s ability to choose pregnancy should they want to choose pregnancy,” said Woodruff.

Among environmental pollutants, endocrine-disrupting chemicals, in particular, are a fertility concern, she said:

“We know that the number and amount of them are increasing and we know that some of them can directly impact male and female reproductive health.”

It is difficult to fully calculate the role of environmental pollutants in infertility since “we only have data on a very small proportion of endocrine-disrupting chemicals to which we’re exposed,” she added.

About one in six people struggle with infertility, according to the World Health Organization. Research suggests sperm count in men has declined by 1.6% per year since 1973, although the impact on global fertility is unknown, the paper states.

Some data suggests that proximity to major roadways — sources of air pollutants from vehicles — correlates with loss of reproductive potential in women’s ovaries, sperm abnormalities and lower birth rates, said Linda Giudice, an obstetrician, gynecologist and reproductive endocrinologist at the University of San Francisco and former IFFS president who participated in the paper’s review committee.

Data also ties the chemicals bisphenols, dioxins and phthalates with decreased fertility, altered sperm, higher miscarriage rates and lower rates of conception, she said.

Higher use of two common types of insecticides, organophosphates and N- methyl carbamates, is associated with lower sperm concentrations in men, according to a review published in the journal Environmental Health Perspectives in November 2023.

To decrease the impact of environmental toxins on reproductive health, policies should address risks from both chemicals currently in use and those that will emerge in the future, said Shanna Swan, an environmental and reproductive epidemiologist at the Icahn School of Medicine at Mount Sinai in New York and author of a 2021 book on how chemicals in the modern environment endanger fertility.

“Demonstrating that new chemicals are not reproductive toxins prior to introduction into commerce is difficult but a necessary step to help reduce the rapid declines that have been identified is removing known reproductive toxins,” said Swan.

Beyond infertility linked to environmental and lifestyle factors, the paper’s authors concluded that the trend in the global fertility rate is partially driven by education levels, discrimination against women and lack of support for working parents.

Additionally, women are increasingly choosing to have children at an older age, when their fertility has naturally declined, a factor that also contributes to lower global fertility rates, the paper states.

Some environmentalists have suggested that a world with fewer people would be better for both humans and the environment, but the new paper states that global population decline would have “major societal and economic implications that will severely challenge nations and the global community.”

“Something needs to be done before it is too late,” said IFFS President Edgar Mocanu.

Originally published by The New Lede

Shannon Kelleher is a staff reporter for The New Lede.

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