Shanna Swan: ‘Most couples may need to use supported reproduction by 2045’ | Fertility problems

Shanna Swan is a professor of environmental medicine and public health at Mount Sinai Medical School in New York City, studying fertility trends. In 2017 she recorded how average sperm counts among western men have more than halved in the last 40 years. Count down her new book.

You have spent more than 20 years studying the effects of chemical-disturbing chemicals on reproductive health. Are you now sounding the alarm?
I’m talking directly to this hidden problem that people don’t like to talk about, which is their underfertility or reproductive problem, and how that relates to the environment. People recognize that we have a reproductive health crisis, but they say that it is due to a delay in childbirth, choice or lifestyle – it cannot be chemical. I want people to recognize that they can. I am not saying that other factors are not involved. But I do say that chemicals play a big part. That word, “reason” is difficult to use, but it is a body of evidence. We have mechanisms, animal studies, and human multiple studies.

Female pregnancy declines sharply after around 35. Isn’t that why so many men are turning to IVF?
It’s not that simple. When a colleague and I watched the change in lack of finances [the ability to have children] it surprised us to see younger women on a larger rise than older age groups. This suggests that fertility is affected by something other than aging and delayed childbirth.

In addition, there is strong evidence that the risk of childbirth has increased among women of all ages.

What chemicals are the biggest concern for reproductive health and how do they work?
The ones that can inhibit or mimic the body’s sex hormones – such as testosterone and estrogen – because these make reproduction possible. They can make the body think that it has enough of certain hormones and does not need to do more, so yield goes down.

Phthalates, used to make plastics soft and flexible, are extremely important. They are in everyone and we tend to be open through food because we use soft plastics in food manufacturing, processing and packaging. They reduce testosterone and so on the strongest effects on the male side, for example reducing sperm count, although bad for women, have also been shown to reduce libido and increase the risk of early puberty, pre-ovarian failure. premature, premature birth and premature birth.

Bisphenol A (MSP), which is used for hardening plastic and found in cash register receipts and lining of some food containers in cans, is another. It mimics estrogen so it is a very bad performer on the female side, increasing risks for pregnancy, but it can also affect men. Men exposed to MSPs have been shown to have reduced sperm quality, decreased libido and higher levels of erectile dysfunction. Other harmful chemicals include flame retardants and some toxins such as atrazine.

When is the greatest damage done?
Much of the cause of these changes occurs in utero when the fetus first forms. These rapidly dividing cells are the most sensitive. The blows then continue through childhood, adolescence and adulthood. This has a cumulative nature. And we can deliver those effects. The simplest way is by direct exposure. A female fetus, in utero, grows the eggs which she uses to have her own children. These chemicals can also make their way to these germ cells.

What is the anogenital distance (AGD) and why is it important?
It is the distance from the anus to the genitals and is usually much longer in males than females. It is an indicator of the level of androgen [male sex hormones including testosterone] a child was exposed during pregnancy. AGD is such an important indicator of reproductive health and endocrine dysfunction – if we measured it for every child, we would know something about their future fertility. Shorter AGDs in men and longer AGDs in women indicate less reproductive success.

You have used AGD to show that phthalates cause low sperm count in men. How come?
When I first started looking at phthalates, around 2000, phthalate syndrome was shown experimentally in rodents but not in humans. Male infants with pthalates called male infants with smaller penis and scrotum, lower sperm counts and shorter AGD. I ran a study where we measured the urine of pregnant women for phthalates and measured the AGDs of the male and infant babies – the first one – along with some other genetic measurements. We found out exactly what was found in rodents: phthalate syndrome. I then studied men of college age, where we got them to provide a semen sample and measure their AGD, and we showed that the shorter the AGD, the lower the sperm count. That’s why I’m confident: we have a direct link from phthalates to short AGD and then from short AGD to low sperm count, and these results have been confirmed by subsequent studies.

How terrible is the reproductive crisis? You said we are on track for a barren world by 2045…
It’s bad. If you follow the curve from the 2017 sperm decline meta-analysis, it predicts that we will have a median sperm count of zero by 2045. It is an approximate omission, but there is no evidence that it is growing narrower. This means that most couples may need to use supported reproduction.

Drugs are monitored for safety. What are the regulatory conditions for these chemicals?
In the US, most chemicals have not been tested and are considered safe. There has been better progress in Europe. Although incomplete, EU regulation (Registration, Evaluation, Authorization and Restriction of Chemicals) was a major step forward. Stronger economic interests prevent stricter regulation.

What needs to happen?
The chemical industry needs to start making chemicals that can be used in everyday products that are not hormonally active. Difficult substitution – where one harmful chemical is replaced by another that has not been tested, and which are then the same hazards – must also stop. It has occurred with various phthalates, BPA and flame-retardants and is not permitted. And we need to test the chemicals we use right now – and not just at high doses and not just one at a time, because we are open to a large number.

Should we believe packaging that says MSP or phthalate free?
If it says “MSP free” it may not have an MSP. But note that it does not say bisphenol free so you could still get bisphenol S or F, which are difficult substitutes. Phthalate free I would also be suspicious. While it may be free from the old famous actors, it may not be free from newer ones. People should feel angry about being deceived in this way and push for change.

What should we be doing to reduce our exposure?
People of reproductive age, especially those planning a pregnancy or pregnancy, should be aware that everything they bring into their home has the potential to absorb these chemicals. . As far as possible, eat processed foods – a handful of carrots, potatoes that you cook yourself – as this should reduce exposure through plastic. Also, when cooking, do not use Teflon or anything with a lid and do not put a microwave in plastic. For personal care and home products use at least simple products and try to avoid the fragrant ones; phthalates are added to retain odor. The Nonprofit Environment Working Group has a free user guide that provides information on specific products.

Can we turn things around?
I think we can. We have the innovation and the resources to do it. But we need to recognize the problem and the will to change.

Count down: How our modern world threatens sperm numbers, alters male and female reproductive development, and affects the future of humankind by Shanna H Swan by Stacey Colino published by Simon & Schuster (£ 20). To order a copy go to Delivery costs may apply