Birth rates in men are declining and may be due to environmental toxins

In the United States, one in eight couples infertility.. Unfortunately, doctors like me who specialize in reproductive medicine cannot determine the cause of male infertility with a 30% to 50% chance. It’s rarely as disappointing as telling a couple “I don’t know” or “I have nothing I can do”.

Upon receiving this news, couples ask me questions one after another, but they all follow a similar idea. “What about his work, his cell phone, our laptop, all these plastics? Do you think they were able to contribute to this?”

Patients really want a big problem in male reproductive health. Does environmental toxicity contribute to male infertility?

Declining birth rate for men

A medical professional sitting with a couple. Infertility is defined as the inability of a couple to become pregnant for a year despite regular sexual intercourse. In this case, the doctor will evaluate both partners to determine the reason.

For men, the basis of fertility assessment is semen analysis, and there are several ways to assess sperm. Sperm count (total number of sperms produced by men) and sperm concentration (sperm count per milliliter of semen) are common indicators but are not optimal predictors of fertility. For a more accurate measurement, look at the total number of motile sperm. It assesses the percentage of sperm that can swim and move.

From obesity to hormonal imbalances to genetic disorders, a variety of factors can affect childbirth. For many men, there are treatments that can help. However, since the 1990s, researchers have noticed a tendency to worry. Even with controlling many of the known risk factors, male fertility appeared to have declined over decades.

A 1992 study found that male sperm counts have declined by 50% worldwide over the last 60 years. Studies over the next few years confirmed the first findings, including a 2017 paper showing that sperm levels decreased by 50% to 60% in men worldwide between 1973 and 2011. ..

These studies are important, but focus on sperm concentration or total sperm count. Therefore, in 2019, a team of researchers decided to focus on stronger total motile sperm counts. They found that the proportion of men with normal total motile sperm counts decreased by about 10% over the last 16 years.

Science is consistent. Men today produce less sperm and are in poorer sperm health than in the past. Therefore, the problem is that it may be causing this decline in fertility.

Environmental toxicity and reproduction

Scientists have long known that environmentally toxic exposure can alter hormonal balance and inhibit reproduction, at least in animal models. Researchers cannot intentionally expose human patients to harmful compounds to measure their results, but they can assess their relevance.

As the declining trend of male fertility became apparent, I and other researchers began to look more closely at chemicals in the environment in search of answers. While this approach cannot clearly identify which chemicals are causing the decline in male fertility, the evidence is becoming more important.

Much of this research focuses on endocrine disruptors, molecules that mimic the body’s hormones and upset the fragile hormonal balance of reproduction. These include substances such as phthalates, well known as plasticizers, pesticides, herbicides, heavy metals, toxic gases and other synthetics.

Plasticizers are found in most plastics, such as water bottles and food containers, and exposure adversely affects the health of testosterone and semen. Herbicides and pesticides are abundant in food supply, and some, especially those containing synthetic organic compounds containing phosphorus, are known to adversely affect childbirth.

Air pollution surrounds cities and exposes residents to particulate matter, sulfur dioxide, nitrogen oxides, and other compounds that can contribute to abnormal sperm quality. Radiation exposure from laptops, cell phones and modems is also associated with decreased sperm count, decreased sperm motility, and abnormal sperm morphology. Heavy metals such as cadmium, lead and arsenic are also found in foods, water and cosmetics and are also known to harm sperm health.

Endocrine disruptors and the problems of infertility they cause have a significant impact on human physical and emotional health. And treating these harms is expensive.

Impact of unregulated chemicals

Many chemicals are used today and it is very difficult to track them all. Currently, over 80,000 chemicals are enrolled in the National Toxicology Program.

When the program was established in 1978, 60,000 of them were exempted from the program with minimal information and nearly 2,000 new chemicals were introduced each year. Many scientists say that health and environmental risk safety testing is not strong enough, and the rapid development and introduction of new chemicals challenges the organization’s ability to test long-term risks to human health. believe.

Current US national toxicology regulations follow the principle of innocence until proved guilty and are less comprehensive and less restrictive than similar regulations in Europe, for example. The World Health Organization has recently identified 800 compounds that can destroy hormones, but only a few of them have been tested.

The American Chemistry Council, an industry group, said on its website that manufacturers “have the regulatory certainty they need to innovate, grow, create jobs and win the global market, while at the same time providing public health and the environment. We are benefiting from strong risks. ” Base protection. “

However, the reality of the current regulatory system in the United States is that chemicals are introduced with minimal testing and are removed from the market only if harm is proven. And it can take decades.

Dr. Niels Skakkebaek, Principal Investigator on one of the first manuscripts on sperm count reduction, called the decline in male fertility “a wake-up call to all of us.” My patients have provided me with an awakening call that raising public awareness and advocacy is important to protect current and future global reproductive health. I’m not a toxicologist and I can’t pinpoint the cause of the infertility propensity I’m seeing, but as a doctor, I suspect that much of the burden of proof rests with the human body and those who become my patients. I am worried.

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