Male fertility: 5 reasons behind falling sperm count

The concentration of sperm that men release during ejaculation has dropped by 51% over the past 50 years.

This is one of the main findings of recently published research carried out at the Hebrew University of Jerusalem, in Israel, and at the Mount Sinai School of Medicine, in the United States.

The researchers calculated that, in the 1970s, men had 101 million reproductive cells per milliliter of semen, on average. That figure dropped to 49 million recently.

In addition to quantity, evidence also points to a decline in the quality of male gametes: the percentage of cells able to enter the ovule has suffered considerable declines in recent decades.

“The most striking thing we see is the loss of sperm movement. Without this attribute, the ability to fertilize is reduced”, observes urologist and andrologist Moacir Rafael Radaelli, vice-president of the Brazilian Association of Assisted Reproduction.

This scenario of constant worsening turns on the warning signal among health professionals.

“It is something worrying, because we see an acceleration of this worsening and we don’t know very well where it will end”, evaluates the doctor Eduardo Miranda, coordinator of the Department of Andrology of the Brazilian Society of Urology.

In fact, the rate at which men lose sperm has increased in recent years. According to the same work carried out in Israel and the USA, between the 1970s and the 1990s, the concentration of gametes fell by 1.16% a year.

But, starting in the 2000s, this rate rose to 2.64%. In other words, it more than doubled.

And this is a global phenomenon: scientists have observed a reduction in gametes in men on all continents, although the numbers are more accelerated in Europe, Africa, Central and South America.

But what is behind the phenomenon? Experts point to at least five causes. The good news is that there are ways to reverse or mitigate them.

1. Obesity

The extra kilos promote a veritable package of harmful changes to spermatozoa.

The growth of adipose tissue, which stores fat, releases inflammatory substances that directly affect testosterone, one of the most important hormones in the production of male gametes.

Miranda points out that being overweight also generates the so-called oxidative stress, a process in which several cells in the body end up being harmed.

“In addition, the obese individual has more fat in the genital region, which is terrible for the spermatozoa”, says the urologist.

The testicles, where reproductive cells are manufactured and stored, need to be between 1 and 2 °C below the body’s temperature to function well – that’s why the scrotum is outside the body.

The issue is that this increase in fat heats up the reproductive organs, which stop working as expected.

The World Health Organization (WHO) calculates that 39% of men are overweight and 11% are obese across the globe — a statistic that helps explain this drop in the proportion of spermatozoa over the last five decades.

2. Substance abuse

Alcohol, cigarettes, vaping, hookah, marijuana, cocaine, anabolic steroids… Do you know what all these drugs have in common? They affect the health of male gametes.

“Some of these substances directly damage the germ cells, which give rise to sperm”, summarizes Miranda.

Others, however, act indirectly. They affect the production of hormones responsible for stimulating the work of the testicles.

The most cited example among experts is testosterone replacement through pills, gels and injections, used indiscriminately as a way to gain muscle.

“This is a market that has grown insanely and frighteningly in recent years”, warns Radaelli.

The doctor explains that when the replacement of this hormone is done without a well-defined indication, the body understands that there is no longer a need to produce it naturally.

As a result, the testicles can even atrophy and the sperm count in the semen ends up at zero, in a condition known in medicine as azoospermia.

3. Sexually transmitted infections

Diseases such as chlamydia and gonorrhea, caused by bacteria, can cause inflammation in the epididymis.

This structure connects to the top of the testicles and is responsible for storing sperm.

An alteration there, therefore, poses a risk to the survival of the gametes.

The WHO estimates that, in 2020 alone, there were 129 million new cases of chlamydia and 82 million of gonorrhea among men and women. This rate has remained stable or on the rise in recent decades.

Radaelli adds a third pathogen to the list: the human papillomavirus, also known by the acronym HPV.

“It is known that it can also affect the production or even the DNA of sperm,” he says.

4. Computer on lap

Remember that story that the testicle needs to stay between 1 and 2°C below the temperature of the rest of the body?

Well, studies published in the last decade have revealed that the habit of keeping a notebook on your lap represents an additional risk for the gamete factory.

That’s because the device’s battery heats up — and it may end up “cooking” the sperm.

Miranda points out that other habits related to higher temperatures also pose risks to reproduction.

This is the case, for example, with long baths in a bathtub with hot water or long hours in saunas.

Still in the field of technology, the doctor cites the possible effect of electromagnetic waves, telephone signals and even wireless internet.

“In experimental studies, carried out in the laboratory, elements such as wi-fi and electromagnetic waves affect spermatozoa”, he informs.

“But it is still not possible to be sure whether these technologies really represent damage to these cells”, he ponders.

5. Endocrine disruptors

To close the list, specialists draw attention to a series of toxic compounds known generically as endocrine disruptors.

The list includes pollutants detected in the atmosphere, as well as plastics and pesticides.

In short, these molecules have a structure very similar to the hormones in our body.

With that, in the same way that a key enters the lock, these substances manage to fit into cell receptors and trigger some unwanted processes.

One of these developments detected in recent studies has to do precisely with male fertility.

“But we still don’t know for sure the extent of this problem and there are many studies in progress to determine this”, says Radaelli.

An infertile world?

In addition to the environmental and behavioral factors behind the drop in sperm, there are two intrinsic issues that also contribute to the phenomenon.

The first of these is genetics. It is estimated that between 10 and 30% of cases of difficulty having a child have to do with a problem in the male DNA.

The second is related to aging and the fact that men seek fatherhood later and later.

“We know that the fertile capacity decreases throughout life. Although the decrease in men is not as pronounced as in women, there is a reduction in hormones that are important for the manufacture of gametes”, he explains.

If we consider that sperm counts have dropped 51% in 50 years and the rate at which this has been happening has accelerated in the last two decades, is that the trend for this number to get closer and closer to zero?

After all, if this rate of decline continues at current levels, by 2050 the concentration of reproductive cells in semen would be practically zero.

But Miranda doesn’t think this doomsday scenario will come true.

“The tendency is for the situation to get worse, but at some point this process will stagnate and we will reach a plateau, perhaps with the help of new technologies”, he bets.

What to do?

For those who want to have a child, the first step towards increasing the chances of success involves making some lifestyle changes and, thus, reversing the deleterious processes to the testicles.

This involves, for example, maintaining or losing weight through a balanced diet and regular physical activity. Avoiding or completely avoiding alcohol, cigarettes and other drugs is also a basic recommendation.

If sex is recreational, with occasional partners and without the aim of getting pregnant, it is always worth using a condom to avoid infections such as chlamydia and gonorrhea. Individuals who take the HPV vaccine in early adolescence are also more protected from this virus and the repercussions it causes on the body.

If, even with all these changes in routine, the difficulty in having a child remains, it is worth seeking a doctor.

According to national and international guidelines, the time to seek a specialized evaluation will depend on the woman’s age.

“If she is under 35 years old, the couple should try to have a child for up to one year, with regular sexual intercourse around three times a week, with monitoring of the fertile periods”, points out Miranda.

Now, if the partner is over 35, a difficulty conceiving for more than six months should already turn on the warning signal.

This is because the reserve of eggs from that age begins to fall more quickly – and a delay of 12 months to find answers can represent a waste of time that is very valuable, point out doctors.

“The investigation needs to involve the couple to discover possible causes and indicate the best treatments”, reinforces Radaelli.

If the problem is in the male part, specialists usually prescribe vitamin supplements rich in antioxidants, which help protect the testicles.

It may also be necessary to regulate hormones through supplementation.

“And, of course, it is possible to correct some of the diseases that are at the origin of the problem through medication and surgery”, says Miranda.

“It is the case, for example, of treating bacterial infections with antibiotics and anatomical defects in the reproductive system with surgical interventions”, he concludes.

As a last resort, the couple can use assisted reproduction techniques, such as in vitro fertilization.

This text was originally published here.