Meta AnalysisHumann = 223 studies, 288 estimates2023
Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries.
Plain-language summary
This study set out to examine global trends in sperm count over the past several decades. It pooled data from 223 studies, including semen samples collected from men worldwide between 1973 and 2018, and analyzed sperm concentration (SC) and total sperm count (TSC). The analysis found that sperm counts have declined significantly over this period, with steeper declines among unselected men from North America, Europe, and Australia, and a notable drop also seen among men from South/Central America, Asia, and Africa. The decline appears to have accelerated since 2000.
Key findings
- Sperm concentration declined by 51.6% globally between 1973 and 2018.
- Total sperm count declined by 62.3% globally over the same period.
- Declines were steeper among unselected men from North America, Europe, and Australia.
- The rate of decline doubled after 2000, from 1.16% to 2.64% per year.
How to analyze the study yourself
- Study type
- Meta-analyses pool data from multiple studies to identify broader trends, but they rely on the quality and consistency of the included studies, which can vary.
- Population
- Men from North America, Europe, Australia, South/Central America, Asia, and Africa, with semen samples collected between 1973 and 2018.
- Funding
- Not reported
- Takeaway
- This study found that sperm counts have dropped sharply worldwide since the 1970s, with the decline speeding up after 2000. The study did not investigate potential causes or solutions. If you are concerned about fertility, it is worth reading more recent studies to learn what you can do to improve your chances of conceiving.