Reproductive crisis? Sperm counts dropping rapidly worldwide

Mean sperm count dropped to 49 million/ml from from 104 million/ml in 46 years

By Susan Chacko
Published: Tuesday 29 November 2022
Having a low sperm count can make it more difficult to conceive naturally. Photo: Wikimedia Commons
Having a low sperm count can make it more difficult to conceive naturally. Photo: Wikimedia Commons Having a low sperm count can make it more difficult to conceive naturally. Photo: Wikimedia Commons

New research has found sperm counts are decreasing at an accelerated rate worldwide. Total sperm count has reduced by less than half in less than five decades, suggesting an emerging reproductive crisis. 

There has been a decline in total sperm counts (TSC) and sperm concentration (SC) among unselected men and people with external gonads from South America, Central America, Asia and Africa, reported a meta-analysis. The study was published in journal Human Reproduction Update November 15, 2022.

Read more: Celibacy: its surprising evolutionary advantages – new research

The study was led by Hagai Levine from Hebrew University of Jerusalem, Israel. The decline in sperm counts in North America, Europe and Australia, reported by the same team in 2017, has continued and has even accelerated in the 21st century, the analysis showed. 

Sperm counts dropped by 1.2 per cent per year from 1973 to 2000. The decline worsened from 2000-2018 to 2.6 per cent per year, the study found. 

“Overall, we’re seeing a significant worldwide decline in sperm counts of over 50 per cent in the past 46 years, a decline that has accelerated in recent years,” Levine said. Mean sperm concentration has dipped to 49 million/millilitres from 104 million/ml. 

This means a substantial increase in the proportion of men with delayed time to conception on a population level. The study did not examine the causes of sperm count declines.

The analysis called for more research on the causes of this continuing decline and actions to prevent further disruption of male reproductive health.

The analysis with data from 6 continents and 53 countries included results from 223 studies. It yielded 288 estimates based on semen samples collected from 1973-2018.

low sperm count, also called oligozoospermia, is where a man has fewer than 15 million sperm per millilitre of semen. Having a low sperm count can make it more difficult to conceive naturally.

Sperm count is not only an indicator of human fertility but also an indicator of the health of people with external sex organs. Low levels of sperm are associated with an increased risk of chronic disease, testicular cancer and a decreased lifespan.

A significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011 was reported by a 2017 study by Hagai Levine & et al. The decline was “driven by a 50-60 per cent decline among men unselected by fertility from North America, Europe, Australia and New Zealand,” the report said. 

The decline in sperm counts is a “global crisis in male reproductive health,” said a research paper published by C De Jonge and C L R Barratt in Andrology (June 26, 2019). It urged for increased research into male reproductive biology.

Read more: Inequalities in accessing sexual, reproductive healthcare persist: WHO study

Advanced paternal age, along with paternal lifestyle factors such as obesity and smoking, impact not only male fertility but also the offspring’s wellness, suggested another study.

The Male Reproductive Health Initiative (MRHI) was launched in 2018. MRHI is a global collaboration of more than a dozen key opinion leaders in research, medicine and patient support groups from the Americas, Australia, the United Kingdom, and Europe.

“Society needs to be informed of what we learn from studying male reproductive fitness and health risks, with a focus on specific geographical areas,” said Canadian andrologist Chris De Jonge, one of the founding members of the MRHI.

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