An expert in fertility from the University of Nottingham will feature in a new documentary looking at how exposure to man-made environmental chemicals have been linked to declining reproductive function in humans and animals.
Professor Richard Lea, from the University's School of Veterinary Medicine & Science, features in 'Infertile' – which is released on 8 July and produced by Escapade Productions. It highlights the scientific evidence that underpins these alarming global effects.
We are exposed to mixtures of chemicals day in and day out, and many of these chemicals block or mimic hormone action. The implications of this, is that the developing unborn baby and newborn, that relies heavily on hormonal cues in order to develop properly, may be affected by exposure with consequences for reproductive health in adult life."
In humans, sperm counts have declined for over 50 years and there are more baby boys born with undescended testicles (cryptorchidism). In women, reproductive health has similarly declined with increased incidences of premature ovarian failure, early puberty and an increased incidence of breast and other reproductive cancers.
"Although these changes over time are associated with exposure to chemical pollutants, it's difficult to demonstrate cause and effect," says Professor Lea.
To address this, Professor Lea and colleagues have investigated sperm quality in healthy stud dogs from an assistance dog breeding programme.
Professor Gary England, also from the University's School of Veterinary Medicine & Science, working with Professor Lea said: "Since the dogs live in normal homes and are regularly checked for reproductive and general health, we could investigate changes in sperm quality over time."
In a pivotal paper published in 2016, and in subsequent studies, Lea and colleagues have shown that sperm quality has declined in these stud dogs at a rate that parallels that seen in humans. Also, within the same population of dogs, more pups are being born with undescended testes, just like in the human.
Professor Lea said "Since numerous dogs are castrated for veterinary reasons, this provided us with surplus tissue that would otherwise be discarded. Using these samples, we have shown that chemicals are present in testes where sperm is produced and worryingly, they are able to reduce the motility of sperm in short-term incubation, even at the concentrations detected."
Professor Lea and colleagues from the Universities of Glasgow and Michigan, also describe studies in sheep that have been exposed to chemicals in processed human sewage-based fertiliser. Commonly used by farmers, the fertiliser contains mixtures of chemicals that primarily come from humans. Consequently, while grazing the pastures, pregnant ewes and their unborn lambs are exposed to similar mixtures of chemicals that approximate our own exposures.
The Infertile documentary explores this work within the context of other studies in humans and animals around the World. Launched on 8 July, the documentary is pivotal in raising public awareness of this global crisis.
Professor Lea said: "The release of this documentary at a time when global fertility is declining, is crucially important. We must take action now to mitigate against the effects of environmental contaminants – ultimately this will protect reproductive health in future generations!"
Professor Lea also attended the launch of the Plastic Babies campaign, in the House of Lord on 9 June, emphasizing the need to limit exposure of babies to plastics during the first 1000 days of life.
The trailer to the 'Infertile' documentary can be viewed here.
