Doctors raise alarm on dropping global fertility rate, environmental pollutants cited
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
Wednesday in the journal Human Reproduction Update. The researchers – who
come from multiple countries, including the United States, 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, is launching a global campaign 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.
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.