Tag Archives: fertility

male depression

Major depression in men makes couples less likely to conceive

New research suggests that a man’s poor mental state can affect the ability of a couple to conceive.

male depression

Credit: Pixabay.

Researchers at the National Institutes of Health combined data from two previous studies that compared the effectiveness of ovulation-inducing drugs in women with polycystic ovary syndrome and couples with unexplained fertility. Most of the 1,650 women and 1,608 men involved in the dataset formed couples.

Based on the results of a questionnaire, about 6% of women and 2% of men were rated as having major depression, and this was found to have a major impact on fertility. Men with major depression were 60% less likely to have a live birth compared to men who did not have major depression. The study did not include couples who underwent in vitro fertilization since the procedure couple potentially offset some of the effects of depression.  

Of the 34 men with major depression, only three achieved a live birth. That’s compared to nearly 25% of couple who achieved a live birth, where the male partner did not have major depression.

Depression may affect fertility in men in a number of ways, including sexual dysfunction due to reduced libido and negative change in sperm quality. For instance, a study published in 2014 found that men who had gone through two or more stressful events the previous year had lower sperm motility and a lower percentage of normal sperm. Stress also lowered testosterone levels, which is a hormone known to be heavily involved in fertility.

Previously, studies had shown that depression negatively affects fertility in women. For instance,  41 percent of women seeking fertility treatments have symptoms of depression. The present study is the first to show that depression also affects male fertility, providing “new information to consider when making treatment decisions.”

A secondary finding of the study was that a class of antidepressants known as non-selective serotonin reuptake inhibitors (non-SSRIs) was linked to a higher risk of early pregnancy loss among females being treated for infertility. SSRIs, another class of antidepressants, were not linked to pregnancy loss.

Scientific reference: Emily A. Evans-Hoeker et al. Major depression, antidepressant use, and male and female fertility, Fertility and Sterility (2018). DOI: 10.1016/j.fertnstert.2018.01.029. 

sperm count

Western males have lost nearly 60% of their sperm count since the 1970s

A striking new study published in the journal Human Reproduction Update found a drastic drop in both sperm concentration and sperm count among men in the Western world. According to data from 185 studies spanning 1973 to 2011,  the researchers saw a 52.4 percent decline in sperm concentration and a 59.3 percent decline in total sperm counts. Though there’s isn’t any official explanation yet, scientists think this steep decline in sperm count might be caused by exposure to new man-made chemicals like certain pesticides.

sperm count

Men’s sperm is not as ‘bright’ as it used to be. Credit: Pixabay.

The study covered men living in North America, Europe, Australia, and New Zealand who saw a steep decline in sperm count and concentration that wasn’t reported elsewhere. However, this may be due to the fact that proper data is less readily available in non-Western countries so it may be that men in Southeast Asia or Africa, for instance, may see similar significant reductions in sperm quality. We just don’t have the data yet.

A man’s fertility generally relies on the quantity and quality of his sperm. If the number of sperm a man ejaculates is low or if the sperm is of a poor quality, it will be difficult, and sometimes impossible, for it to lead to a pregnancy. But though the new findings might sound disturbing — after all, we’re talking about men who now have half as much sperm as they did 50 years ago — significant effects on population growth will only be seen when a significant proportion of the population has very low fertility.

At the same time, given the significant public health risks, the findings warrant urgent research. Previously, studies found that sperm count is related to increased morbidity and mortality, besides the obvious problems relating to fertility. Already, the fraction of men whose sperm counts are below the threshold for subfertility or infertility is increasing.

Credit: Hebrew University.

Credit: Hebrew University.

According to lead researcher Hagai Levine, an epidemiologist and public health physician at the Hebrew University-Hadassah, we don’t yet know for sure what caused this steep drop in sperm. We do know, however, that endocrine disruptor exposure in utero, such as stress or smoking while the mother is pregnant, can harm the male’s fertility potential. It’s far more likely, however, that exposure later in life from man-made chemicals like pesticides or the effects of obesity cause such a pronounced effect.

“One possible explanation is that men residing in Western countries over the last decades were exposed to new man-made chemicals during their life course, and there is more and more evidence that these chemicals hurt their reproductive function. We also need local knowledge regarding exposure and effects. For example, I am studying pesticides exposure and male fertility in Israel, as pesticides exposure is common,” Levine told ResearchGate. 

Nobody knows if this trend will continue on its descending path. One could argue that at some point the existence of our whole species could be threatened if sperm count drops at its current rate. The truth is we don’t know much yet. We just know things are bad right now and more urgent research is required to get to the bottom of things before it might be too late.

Male dogs are becoming less fertile, and researchers believe it’s happening to us next

Researchers have determined that the fertility of male dogs all over Britain has been steadily declining over the past three decades, for a whopping 30 percent across five common breeds. There isn’t any real danger of them losing their ability to reproduce anytime soon, but the findings could have serious implications for their human owners, the team believes.

My what does WHAT?!
Image credits Zach Zupancic/Flickr.

Ok, I don’t know about you but there’s two things that consistently make my day better no matter what’s going down: the dog jumping up and down for joy when he sees me come home, and the fact that my plumbing works like a charm. But, in a kind of depressing quantum link, the two of them seem to be connected — and science says there’ll be a whole lot less up and down going on.

“The dogs who share our homes are exposed to similar contaminants as we are, so the dog is a sentinel for human exposure,” said lead researcher Richard G. Lea, from the University of Nottingham in the UK, for the The New York Times.

Lea and his team have been assessing the fertility of a population of male service dogs at an English center for disabled people. They started in 1988, and since then they’ve analyzed a total of 232 dogs of five different breeds — Labrador retrievers, golden retrievers, curly coat retrievers, border collies and German shepherds. The team chose to work with these dogs because their health and lineage are excellently recorded and they’re all being raised in one location in the same conditions.

Each year, the team would test the fertility of a selection of 42 to 97 dogs via sperm samples. At varying intervals throughout the 26 years of study, the dogs with the poorest sperm quality were removed from the test group. When they measured the percentage of sperm with healthy motility — the ability to swim in a straight line — the researchers found that it dropped by 2.4% each year. Even when not taking data from the dogs who were removed into account, sperm motility declined by an average of 1.2% every year from 2002 to 2014, for an overall decline of 30% over the entire study’ duration.

And the bad news don’t end here.

“Between 1994 and 2014, they also noticed that the mortality rate of the female puppies, although small, showed a threefold increase,” writes Jan Hoffman for the NY Times. “And the incidence of undescended testicles in male puppies, also small, had a 10-fold increase, to 1 percent from 0.1.”

Lea’s team isn’t sure what’s causing this, but they believe that it all comes down to the presence of environmental chemicals called PCBs and phthalates in the dog’s semen and testicles (removed by vets during routine desexing procedures.) Once widely used for paints and plastic masses, PCBs were banned back in the 1970s and ‘80s, and diethylhexyl phthalate (DEHP) has been noted for its potential health risks. But even if they’ve fallen out of use, their long half-life means that they’re virtually everywhere today. Including, as the team found, in trace amounts in the food the dogs eat.

“The scientists cannot determine how the chemicals were introduced into the food supply; these are not additives,” says Hoffman. “But Lea and his colleagues speculate that they could be in the packaging as well as in water that came into contact with any ingredients.”

Ok, so what do dogs’ little swimmers have to do with us? Well, the same chemicals that affect them affect us, too. There are more than 60 studies that report a recent decline in the quality of human semen in the years between 1938 and 1991. Their results are hotly debated, but the evidence that the incidence of undescended testicles in human babies and cases of testicular cancer are on the rise, isn’t. By itself, however, the data isn’t enough to establish a link between these chemicals and the effects the team is seeing — there are just too many other chemicals at play here.

“If you think about it, we are exposed to a cocktail. Who knows how many chemicals are out there and what they are doing?” Lea said.

“What we have been able to do here is just to pull out ones that we know are present, and we have tested those in terms of their effects and it does suggest there is an impact. The next stage – and it is a big next stage – is trying to tease out what else is there and how those chemicals are interacting.”

The paper, titled “Environmental chemicals impact dog semen quality in vitro and may be associated with a temporal decline in sperm motility and increased cryptorchidism” has been published online in Scientific Reports.

Roundworm infections found to increase fertility in women

A study of 986 Bolivian women found that on average, a lifetime infection  with a type of roundworm named Ascarius lumbricoides led to an extra two children in the family. Their paper, published in the journal Science, suggests that the worm is altering the host’s immune system, making it easier to become pregnant — in effect, the parasite increases female fertility. The researchers hope this discovery will lead to “novel fertility enhancing drugs.”

Infection with a species of parasitic worm increases the fertility of women, say scientists. Image via bbc

“The effects are unexpectedly large,” said Prof Aaron Blackwell, one of the researchers for the BBC News website.

For the Tsimane population in Bolivia, the average family has nine children, and about 70% of the population lives with a parasitic worm infection. The paper suggests that an infected woman’s immune system changes during pregnancy, making their body less likely to reject the fetus. On average, these women had two more children during their lifetime.

“We think the effects we see are probably due to these infections altering women’s immune systems, such that they become more or less friendly towards a pregnancy,” said Prof Blackwell.

Blackwell added that while using the worms as a fertility treatment was an “intriguing possibility,” there is much more work to be done before “we would recommend anyone try this.” But it’s not all roses with parasitic worms. The nine year long study also found that while Ascaris lumbricoides increases fertility in infected women, hookworms had the exact opposite effect, with families showing an average of three less children.

Prof. Rick Maizels, specialized in the workings between parasitic worms and the immune system said: “It’s horrifying that the hookworm effects are so profound, half of women by 26 or 28 have yet to fall pregnant and that’s a huge effect on life.”

Prof Maizels suggested the hookworm may also be causing anaemia and leading to infertility that way.

Bacteria and viruses try to overwhelm the immune system by multiplying rapidly. But parasites have a different strategy, growing slowly and suppressing the immune system, which is why they make vaccines less effective in the host and lighten allergies. This also makes the mother’s drowsier immune system less likely to attack fetal tissue, increasing fertility.

However, the mechanism is yet to be fully understood. Prof Allan Pacey reported that drugs had been administered to the women in an attempt to alter their immune system to boost IVF, but without success.

“It is very surprising and intriguing to find that infection with this particular species of roundworm actually enhances fertility,” said Prof Allan Pacey, a fertility scientist at the University of Sheffield.

He added: “Whilst I wouldn’t want to suggest that women try and become infected with roundworms as a way of increasing their fertility, further studies of the immunology of women who do have the parasite could ultimately lead to new and novel fertility enhancing drugs.”

Currently, one third of global population is believed to be infected with similar parasites.

Happy Couple

Parents live longer than childless couples, study shows

Happy CoupleA new study released by Danish researchers at Aarhus University has found a correlation that suggests that couples that are unable to conceive children have a higher mortality rate than those that are.

The study studied more than 21,000 couples having in vitro fertilization treatment between 1994 and 2005. During this period, 15,210 children were born and 1,564 were adopted. Unfortunately, 96 women and 200 men among the participants died.

When correlated with data of fertile couples, the researchers found that the death rate for childless women was four times as high as those who gave birth to their own child, while childless men were twice as likely to meet an early death. Failing to conceive a child often comes as a heavy burden, and the researchers also looked into this. Their findings suggest childless couples were twice as likely to suffer mental illness as those who adopted children.

The researchers, however, stress that their findings are only based on correlations, not cause-effect. As to why this might happen, study co-author Esben Agerbo, an associate professor at Aarhus University in Aarhus, Denmark makes a guess:

“My best guess is health behaviors,” he said. “When people have kids, they tend to live healthier.”

Couples with children tend to chose a healthier life style that can help them take better care of their young, while also serving as an example. Also, having children may boost a parent’s will to live in the event of a deadly accident or illness. Study critics, however, point out that the study at hand handles a secific situation and cannot be applied to the larger population.

“People having IVF tend to be desperate for a child, if they are unsuccessful they may be depressed- it may even be this rather than childlessness that is playing a part,” Ingrid Collins, a consultant psychologist, said in comments to BBC News on the study.

“It is complicated and many factors play a part in death rates- people with deep spiritual belief, being married, having a higher social class – these can all help in living longer,” she added.

Oddly, the findings are on par with a similar a 2011 Stanford University study that found found childless married men had a higher risk of dying from cardiovascular disease after the age of 50, than men who had two or more children.

The findings were reported in the Journal of Epidemiology and Community Health.

An interesting fact: Male fertility is in the bones

The researchers of the Columbia University Medical Center discovered a nice revealed a nice little nugget of information that will probably astonish most of our male (and probably female) readers. The male fertility is determined partially by the bones.

How exactly does this work and how does this effect us? Well, they’ve discovered that the skeleton in male mice acts as a regulator through a hormone released by bone, known as osteocalcin.

Until recently, the only interactions that we were aware of between the bone and the reproductive system was focused in a huge part on the influence of gonads on the build-up of bone mass.

What’s stunning however, is that although this exchange between the bone and the rate of fertility was mainly based on estrogen, researchers did not find any effect on females. When asked why, they did not elaborate on this.

“We do not know why the skeleton regulates male fertility, and not female. However, if you want to propagate the species, it’s probably easier to do this by facilitating the reproductive ability of males,”

“This is the only rationale I can think of to explain why osteocalcin regulates reproduction in male and not in female mice.” said Dr. Karsenty.

In simpler words, the researchers at the Columbia University Medical Center have no idea why this doesn’t effect females, but I suddenly feel the urge to keep my bones healthy. After all, the DNA in rats is surprisingly similar to ours.