[Seasonal variations influenced the semen quality of the sperm donor in Beijing area].

ABSTRACT

OBJECTIVE: To investigate the change trends of sperm quality with seasonal variations among the volunteers of sperm donors in Beijing area, as well as the relationship between two parameters. METHODS: Semen data from the volunteers of sperm donors in Human Sperm Bank of Peking University Third Hospital were collected using a retrospective study method. The subjects were divided into 4 seasonal groups based on the lunar solar terms and the time of sperm donation. The data were assessed to find whether there were differences in semen parameters among different seasonal groups, and to analyze the change trends and the influence of seasonal factors on semen parameters. RESULTS: A total of 21 174 semen parameter data were analyzed. Firstly, to analyze all data as a whole, in spring, summer, autumn and winter groups, sperm concentration was (106.04±59.67)×106/mL, (97.61±47.41)×106/mL, (100.18±47.17)×106/mL, (100.59±38.68)×106/mL, respectively, and the spring group was significantly higher than the other 3 seasonal groups (P < 0.001); proportion of progressive motility sperm (PR) was 56.49%±12.76%, 58.02%±13.65%, 58.05%±12.36%, and 57.66%±12.61%, respectively, spring group was lower than the other three seasonal groups, and summer group was better among the latter (P < 0.001). There was no difference in normal rate of sperm morphology among the four seasonal groups. The qualified rate of sperm donors in the winter group was higher than that in the other three seasons groups (P < 0.01), while the qualified rate in the summer group was lower than that in the other three seasons groups. In addition, the semen parameters of the volunteers during the screening period and the official sperm donation period were analyzed respectively, which revealed that sperm concentration of spring group was higher than that of summer and winter groups, and PR was lower than that of summer and autumn groups. On account of the semen parameters of official sperm donation period, multiple linear regression analysis found that season was the main factor affecting sperm concentration, the average sperm concentration in spring group was about 6×106/mL higher than in winter group, but PR was 2.9% lower in spring group compared with autumn group (all P < 0.05). CONCLUSION: Season was the influencing factor of semen quality of sperm donors in Beijing area. We recommend spring and winter may be the preferred seasons for sperm donation.