Temporal trends in semen quality at a single reproductive center in Shanghai, China, during 2021–2025 amid the COVID-19 pandemic
- 1International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University
- 2Shanghai Key Laboratory of Embryo Original Diseases
Abstract
Background: Accumulating epidemiological and andrological evidence has raised concerns about potential long-term declines in semen quality worldwide, highlighting the need for sustained, population-specific surveillance. In this study, we retrospectively analyzed temporal changes in semen quality during the period of 2021–2025 amid the COVID-19 pandemic. This work extends our previous report on annual trends in semen quality at the same center from 2015 to 2021.
Methods: This retrospective study evaluated temporal changes in semen quality parameters among 21,932 men who attended a reproductive center in Shanghai between 2021 and 2025, a period characterized by widespread COVID-19 pandemic. After 2–7 days of sexual abstinence, semen samples were analyzed using computer-assisted sperm analysis to assess conventional semen parameters, including semen volume, sperm count, sperm concentration, and sperm motility, as well as sperm kinematic parameters, including curvilinear velocity, straight-line velocity, average path velocity, and beat-cross frequency. To better characterize temporal changes across different baseline semen-quality strata, participants were classified according to the WHO 2010 reference criteria into above-reference-limit and below-reference-limit groups. Differences among groups were assessed using one-way analysis of variance, the Kruskal–Wallis test, independent-samples t-test, and analysis of covariance, as appropriate. In the above-reference-limit group, multiple linear regression models including year, age, and abstinence duration were used to adjust for potential confounders and evaluate temporal trends in semen quality.
Results: In the overall cohort and in both the above-reference-limit and below-reference-limit subgroups, sperm count, sperm concentration, and several CASA-derived kinematic parameters, including curvilinear velocity, straight-line velocity, average path velocity, and beat-cross frequency, generally showed increasing temporal trends from 2021 to 2025. After adjustment for age and abstinence duration, multiple linear regression analyses in the above-reference-limit group supported these associations. Semen volume, sperm count, sperm concentration, curvilinear velocity, straight-line velocity, average path velocity, and beat-cross frequency increased significantly over the study period, with regression coefficients of 0.0876, 4.815, 0.6929, 0.9423, 0.3553, 0.5150, and 0.1172, respectively. In contrast, sperm motility decreased significantly over time, with a regression coefficient of −0.7112.
Conclusion: The observed increases in semen volume, sperm count, and sperm concentration contrast with the declining trends previously reported at the same reproductive center before the COVID-19 pandemic. These findings suggest widespread COVID-19 pandemic have reversed the annual changes in parameters related to semen quality.
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BibTeX
@article{zhu2026temporal,
title = {{Temporal trends in semen quality at a single reproductive center in Shanghai, China, during 2021–2025 amid the COVID-19 pandemic}},
author = {Shiyi Zhu and Jin Dong and Zhengmu Wu and Zhengquan Wang and Jun Yang and Chao Feng and Chunhua Tang and Yuchuan Zhou},
journal = {Frontiers in Endocrinology},
year = {2026},
month = oct,
doi = {10.3389/fendo.2026.1980263},
url = {https://www.frontiersin.org/articles/10.3389/fendo.2026.1980263/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Temporal trends in semen quality at a single reproductive center in Shanghai, China, during 2021–2025 amid the COVID-19 pandemic
AU - Shiyi Zhu
AU - Jin Dong
AU - Zhengmu Wu
AU - Zhengquan Wang
AU - Jun Yang
AU - Chao Feng
AU - Chunhua Tang
AU - Yuchuan Zhou
PY - 2026
DA - 2026/10/16
JO - Frontiers in Endocrinology
DO - 10.3389/fendo.2026.1980263
UR - https://www.frontiersin.org/articles/10.3389/fendo.2026.1980263/full
AB - Background: Accumulating epidemiological and andrological evidence has raised concerns about potential long-term declines in semen quality worldwide, highlighting the need for sustained, population-specific surveillance. In this study, we retrospectively analyzed temporal changes in semen quality during the period of 2021–2025 amid the COVID-19 pandemic. This work extends our previous report on annual trends in semen quality at the same center from 2015 to 2021. Methods: This retrospective study evaluated temporal changes in semen quality parameters among 21,932 men who attended a reproductive center in Shanghai between 2021 and 2025, a period characterized by widespread COVID-19 pandemic. After 2–7 days of sexual abstinence, semen samples were analyzed using computer-assisted sperm analysis to assess conventional semen parameters, including semen volume, sperm count, sperm concentration, and sperm motility, as well as sperm kinematic parameters, including curvilinear velocity, straight-line velocity, average path velocity, and beat-cross frequency. To better characterize temporal changes across different baseline semen-quality strata, participants were classified according to the WHO 2010 reference criteria into above-reference-limit and below-reference-limit groups. Differences among groups were assessed using one-way analysis of variance, the Kruskal–Wallis test, independent-samples t-test, and analysis of covariance, as appropriate. In the above-reference-limit group, multiple linear regression models including year, age, and abstinence duration were used to adjust for potential confounders and evaluate temporal trends in semen quality. Results: In the overall cohort and in both the above-reference-limit and below-reference-limit subgroups, sperm count, sperm concentration, and several CASA-derived kinematic parameters, including curvilinear velocity, straight-line velocity, average path velocity, and beat-cross frequency, generally showed increasing temporal trends from 2021 to 2025. After adjustment for age and abstinence duration, multiple linear regression analyses in the above-reference-limit group supported these associations. Semen volume, sperm count, sperm concentration, curvilinear velocity, straight-line velocity, average path velocity, and beat-cross frequency increased significantly over the study period, with regression coefficients of 0.0876, 4.815, 0.6929, 0.9423, 0.3553, 0.5150, and 0.1172, respectively. In contrast, sperm motility decreased significantly over time, with a regression coefficient of −0.7112. Conclusion: The observed increases in semen volume, sperm count, and sperm concentration contrast with the declining trends previously reported at the same reproductive center before the COVID-19 pandemic. These findings suggest widespread COVID-19 pandemic have reversed the annual changes in parameters related to semen quality.
SN - 1664-2392
ER -