Humans could face a reproductive crisis unless action is taken to tackle falling sperm counts, researchers have warned after finding the rate of decline is accelerating.
a study Published in Human Reproduction Update, based on 153 estimates from men presumably unaware of their fertility, shows that the average sperm concentration fell from an estimated 101.2 m/ml/ml to 49.0 m/ml between 1973 and 2018 – 51.6% reduction. In the same period, the total sperm count decreased by 62.3%.
Research by the same teamA 2017 report found that sperm concn it has more than halved in the last 40 years🇧🇷 However, the lack of data for other parts of the world at the time meant that the findings were focused on a region that included Europe, North America and Australia. The latest study includes more recent data from 53 countries.
A decrease in sperm concentration was observed not only in the previously studied region, but also in Central and South America, Africa and Asia.
What’s more, the rate of decline appears to be accelerating: researchers looking at data collected across all continents since 1972 found that sperm concentration has declined by 1.16% per year. However, when they looked at data collected only since 2000, the decline was 2.64% per year.
“I think this is another signal that something is wrong in the world and we need to do something about it. So yes, I think we have a crisis [had] Better fight now before we reach a tipping point of no return,” said study first author Prof Hagai Levine of the Hebrew University of Jerusalem.
Previous studies have suggested that fertility is impaired if the sperm concentration falls below about 40 m per ml. Although the most recent estimates are above that threshold, Levine notes that this is an average number, indicating that the percentage of men below this threshold will increase.
“Such a decline clearly means a decline in the reproductive capacity of the population,” he said.
Although the study accounted for factors such as age and how often men ejaculate, and excluded men with infertility, it has limitations, including not looking at other markers of sperm quality.
Allan Pacey, professor of andrology at the University of Sheffield, who is not involved in the work, praised the analysis but said he remained on the fence about whether there had been a decline.
“Sperm counting even with the gold standard technique [the laboratory process] “Hemocytometry is really difficult,” he said. “I believe we’ve gotten better over time because of the development of training and quality control programs around the world. I still think that’s a lot of what we’re seeing in the data.”
However, Levin dismissed such concerns, adding that in any case, the decline has become more pronounced in recent years.
Although it is not clear what may be behind the apparent trend, one hypothesis is endocrine disrupting chemicals or others environment Environmental factors can play a role by acting on the fetus in the mother’s womb. Experts say factors such as smoking, drinking, obesity and poor diet can also play a role, and a healthy lifestyle can help boost sperm count.
Tina Kold Jensen of the University of Southern Denmark said the new study repeats a worrying trend. “No matter how many studies you put in, you keep finding the same trend — that’s a little scary to me,” he said.
Professor Richard Sharp, an expert on male reproductive health at the University of Edinburgh, said the new data showed the trend appeared to be a worldwide phenomenon.
Sharpe said the decline may take longer for couples to conceive, and for many, time is not on their side, as they delay conceiving until a woman’s 30s or 40s, when her fertility is already declining.
“The main point to note is that this is extremely bad news for couples’ fertility,” he said.
But Sharpe said: “These problems are not just problems for couples trying to have children. They are also a big challenge for society in the next 50 years, as fewer and fewer young people will be around to work and support the growing older population.
