Impact of geographical and seasonal temperature on sperm parameters in Indian men who were partners in subfertile couples – A retrospective analysis

Objective: To evaluate the impact of seasonal and geographical temperature on sperm parameters in Indian men who were partners in subfertile couples. Methods: A retrospective review of the records of semen analysis from January 2009 to December 2017 that was performed as part of primary evaluation of infertile couple was undertaken. Mean values of various semen parameters were compared between seasons using one-way analysis of variance test followed by Bonferroni pair wise post-hoc comparison test. Bivariate Pearson correlation coefficient was applied to measure the correlation between age, sperm parameters and annual temperature/seasons. The logistic regression analysis was further carried out to identify significant variables contributing to normal progressive motility of sperm. Results: A total of 3 433 reports of semen samples were analysed. There was no significant seasonal variation in the mean volume, concentration, and total motility levels (P>0.05) except the mean values of progressive motility (P<0.001). The mean values of progressive motility during pre-monsoon were significantly higher compared to the corresponding values during monsoon and autumn seasons (P<0.01). In all the seasons, total motility had significant positive correlation with sperm concentration and progressive motility (P<0.05). Pre-monsoon emerged as the significant favourable season to get normal progressive motility level (OR 1.32, 95% CI 1.04-1.68) compared to winter. The chances of getting normal progressive motility reduced due to longer abstinence period (OR 0.87, 95% CI 0.80-0.93). When the temperature was more than 28 °C, the likelihood of getting normal progressive motility decreased (OR 0.70, 95% CI 0.51-0.95). Conclusions: The progressive motility of sperms significantly decreases from pre-monsoon to autumn with recovery towards winter, which substantiates the effect of rising temperature on the progressive motility of sperm. This is clinically important to counsel infertile patients, so that they can plan their treatment accordingly.