Sneak Peek: New Essay

This one's called "There's Got To Be Another Way"

Welcome back. It’s Easter Monday and here’s a gift in lieu of a chocolate egg: a new essay on a recent study that shows SSRIs may be powerful endocrine disruptors when taken by pregnant women. I talked about this in last week’s STUDY ANALYSIS, but I thought I’d go into greater detail and contextualise the study further.

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Increased levels of a human growth factor called activin A during pregnancy can cause irreversible damage to male fetuses, according to a new study published in the journal Frontiers in Endocrinology. In the right quantity, activin A ensures the masculinisation process takes place fully and properly: the testes form, produce testosterone and are populated with germline cells, which will eventually become viable sperm at adulthood. Too much activin A, however, and these things don’t happen as they should do, with the potential for life-long negative effects.

So why does this matter?

Because activin A levels are increased by selective serotonin-reuptake inhibitors (SSRIs)—anti-depressants—and nearly 20% of all women in the US take them. Rates of use are similarly high or even higher in many other countries, including the UK. A significant proportion, perhaps a majority, of these millions of women will remain on this medication if they get pregnant. We don’t know exact numbers, but we do know women are told it’s safe for them to continue taking SSRIs while pregnant, and that attempting to reduce their dosage or come off the pills is likely to be bad for their health. Apart from SSRI use, infections within the womb and pre-eclampsia can also cause significant increases in activin A levels during pregnancy.

What this new study reveals, although the authors don’t acknowledge it, is that SSRI use may be a serious undiagnosed cause of the fertility apocalypse facing the world today. Within the space of a few decades, natural reproduction may cease to be possible if current trends in male fertility continue.

There’s already little evidence that SSRIs actually work. If we needed another reason to abandon our massive reliance on them and find other ways to deal with depression, this is it.

All of the research that took place for the new study took place on mice. Activin A and its role in the development of the fetal testes are identical in humans and mice. The researchers modified female mice to remove a natural activin A inhibitor called inhibin, in order to increase the growth factor beyond normal levels in the bodies of the female mice, and then examined the testes of their male offspring. They discovered that increased exposure to activin A during gestation seriously affected the growth of the Leydig cells, which produce testosterone, and the growth of the germline cells, which become sperm later in life.

That means male mice born to mothers with higher levels of activin A will have lower levels of testosterone throughout their lives and produce fewer sperm in their testes as adults. The results are likely to be the same in humans.

The researchers note that these results “mimic phthalate exposure.” Phthalates are a common class of endocrine-disrupting chemical found in plastics, personal-care products and other commercial items that we’re all exposed to regularly in our day-to-day lives. A great many of these chemicals interact with the body’s hormone receptors, which are found in virtually every cell in the body, in a manner that is closely similar to the natural hormone estrogen. In doing so, they upset the natural hormone balance—men have more testosterone and less estrogen, and vice versa for women—which is crucial to sexual differentiation and development, as well as health more generally.

Low testosterone, birth defects, reduced fertility and infertility, gender dysphoria, cancers, obesity and diabetes have all been linked to exposure to endocrine-disrupting chemicals at every stage of life, from gestation, through childhood and into the teenage years and adulthood. There’s no stage of life at which these chemicals can’t have a negative effect on our bodies, but exposure to them at particular moments, especially during early development, has effects that cannot be reversed.

You only get one chance to develop properly in the womb, to go through mini-puberty—a burst of hormones during infancy—or through big puberty in your teens. There are no second chances. No refunds.

Professor Shanna Swan, a world-leading expert in reproductive health, believes that widespread exposure to endocrine-disrupting chemicals is one of the principal causes of the current global decline in fertility, which is taking on an existential character for humans as a species. In particular, sperm counts have declined to such an extent that within just a few decades it may be impossible for humans to reproduce by natural means. Simply by extrapolating trends in sperm counts, Professor Swan predicts that by 2045, the median man will have a sperm count of zero. That means one half of all men will produce no sperm at all, and the other half will produce so few it doesn’t matter—they won’t get a woman pregnant in a lifetime of Sundays.

And this is before we even factor in the effects of these chemicals on women’s fertility, which are no less drastic than their effects on men’s. A recent study out of Singapore, for example, showed that exposure to a class of chemicals known as per- and polyfluoroalkyl substances, or PFAS, which are used in everything from fire retardants and greaseproof paper to non-stick saucepan coatings, can reduce a woman’s chances of bringing a live baby to full term by as much as 40%. That’s insane—there’s no other word for it.

Of course, it’s not just exposure to toxic chemicals that’s causing these terrible declines in fertility for both sexes. Poor diets and sedentary lifestyles, which lead to obesity and metabolic diseases like diabetes, are also clearly to blame. Being overweight and unfit is a disaster for health across the board.