Seasonal variation and its effect on semen parameters in infertile couples based in a rural setting

Abstract

OBJECTIVE: To evaluate the effect of seasonal variation on sperm parameters from infertile couples in a rural setting. DESIGN: Retrospective cohort chart review. MATERIALS AND METHODS: 3,454 male semen samples were analyzed from the Geisinger Fertility Center in Danville, Pennsylvania from January, 1992 to February, 2009. Patients were male infertility patients between the ages of 18 and 65 years old. Using the Kruskal-Wallis test, the unadjusted relationship between semen parameters and seasonal variation was assessed. Age-adjusted results were checked using log-transformed semen outcomes in regression models with season as the main predictor. Seasons were defined using official calendar season dates (spring, summer, fall and winter). Year trend checks were done as well to rule out semen parameters changing over time instead of seasons. Abstracted data included age of the patient, date the specimen was collected, sperm volume, sperm concentration, total count, motile sperm/ml, total motile sperm, motility (%), percentage of dead sperm, and the percentage of abnormal forms. Results were considered significant when p<0.05. RESULTS: Sperm concentration, total count, motile sperm/mL, and total motile sperm were lowest in the fall season (p <0.0001). Sperm motility (%) was lowest in the winter season (p=0.021). The percent of abnormal sperm was highest in the fall (p=0.0002). There was no statistical significance in semen volume nor the percentage of dead sperm by season. CONCLUSIONS: In a rural setting, it can be concluded that seasonal variation plays a role with respect to several semen analysis parameters. Sperm concentration, total count, percent motility, motile sperm/mL, total motile sperm, and percent abnormal sperm appear to have significant seasonal variation even after adjustment for age and year-cohort trends.