{"id":181884,"date":"2021-03-29T12:01:18","date_gmt":"2021-03-29T11:01:18","guid":{"rendered":"https:\/\/www.transcend.org\/tms\/?p=181884"},"modified":"2021-03-29T10:15:32","modified_gmt":"2021-03-29T09:15:32","slug":"most-couples-may-have-to-use-assisted-reproduction-by-2045","status":"publish","type":"post","link":"https:\/\/www.transcend.org\/tms\/2021\/03\/most-couples-may-have-to-use-assisted-reproduction-by-2045\/","title":{"rendered":"‘Most Couples May Have to Use Assisted Reproduction by 2045’"},"content":{"rendered":"

28 Mar 2021<\/em> -The professor of environmental medicine explains how chemicals in plastics are causing our fertility to decline \u2013 and what we can do about it.<\/strong><\/p><\/blockquote>\n

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Shanna Swan: \u2018In the US, most chemicals are assumed to be safe.\u2019
Photograph: Roger Meissen, Bond Life Sciences Center<\/p><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Shanna Swan<\/em><\/a> is a professor of environmental medicine and public health at Mount Sinai school of medicine in New York City, studying fertility trends. In 2017 she documented how average sperm counts among western men have more than halved<\/a> in the past 40 years. <\/em>Count Down is her new book.<\/em><\/p>\n<\/blockquote>\n

You\u2019ve spent more than <\/strong>20 years examining the effects of hormone disrupting chemicals on reproductive health. Are you now sounding the alarm?<\/strong><\/p>\n

I am directly speaking to this hidden problem people don\u2019t like to talk about, which is their sub-fertility or reproductive problems, and how that is tied to the environment. People are recognising we have a reproductive health crisis, but they say it\u2019s because of delayed childbearing, choice or lifestyle \u2013 it can\u2019t be chemical. I want people to recognise it can. I am not saying other factors aren\u2019t involved. But I am saying chemicals play a major causal role. It is difficult to use that word, \u201ccause\u201d, but it\u2019s a body of evidence. We have mechanisms, animal studies, and multiple human studies.<\/p>\n

Female fertility declines rapidly after about 35. Isn\u2019t that why so many people are turning to IVF?<\/strong><\/p>\n

It\u2019s not that simple. When a colleague and I looked at the change in impaired fecundity<\/a> [the ability to have children] we were surprised to see younger women had experienced a bigger increase than older age groups. This suggests that something besides ageing and delayed childbearing is affecting fertility.<\/p>\n

Moreover, there\u2019s compelling evidence that the risk of miscarriage<\/a> has been rising among women of all ages.<\/p>\n

Which chemicals are the most worrying for reproductive health and how do they work? <\/strong><\/p>\n

Those that can interfere with or mimic the body\u2019s sex hormones \u2013 such as testosterone and oestrogen \u2013 because these make reproduction possible. They can make the body think it has enough of a particular hormone and it doesn\u2019t need to make any more, so production goes down.<\/p>\n

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Read more: Sperms’ swimming and navigational skills disrupted by common chemicals<\/strong><\/a><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/figure>\n<\/div>\n<\/div>\n<\/div>\n

Phthalates, used to make plastic soft and flexible, are of paramount concern. They are in everybody and we are probably primarily exposed through food as we use soft plastic in food manufacture, processing and packaging. They lower testosterone and so have the strongest influences on the male side, for example diminishing sperm count, though they are bad for women, too, shown to decrease libido and increase risk of early puberty, premature ovarian failure, miscarriage and premature birth.<\/p>\n

Bisphenol A (BPA), used to harden plastic and found in cash-register receipts and the lining of some canned-food containers, is another. It is oestrogen mimicking and so is a particularly bad actor on the female side, increasing risks of fertility challenges, but likewise it can affect men. Men occupationally exposed to BPA have shown decreased sperm quality, reduced libido and higher rates of erectile dysfunction. Other chemicals of concern include flame retardants and certain pesticides such as atrazine.<\/p>\n

When is the most damage done? <\/strong><\/p>\n

A lot of the exposure that causes these changes occurs in utero when the foetus is first forming. These rapidly dividing cells are the most sensitive. The hits then continue through childhood, adolescence and adulthood. There is a cumulative nature to this. And we can pass these effects on. The simplest way is by direct exposure. A female foetus, in utero, is growing the eggs that she will use to have her own children. These chemicals can make their way to those germ cells, too.<\/p>\n

What is the <\/strong>anogenital distance (AGD)<\/strong> and why does it matter?
\n<\/strong>It is the distance from the anus to the genitals and it is usually far longer in males than females. It is a indicator of how much androgen [male sex hormones including testosterone] an infant was exposed to during early pregnancy. AGD is such an important marker of reproductive health and endocrine disruption \u2013 if we measured it for every infant, we would know something about their future fertility. Shorter AGDs in males and longer AGDs in females indicate less reproductive success.<\/p>\n