Seasonality in sperm parameters in normal men and dyspermic patients on medical intervention.

This study attempted to investigate the presence of seasonal variations in sperm parameters and to evaluate the season's impact on the response to treatment in men with idiopathic oligozoospermia (IO). To this end, a retrospective analysis of the records of 294 men, who participated in a controlled study, was performed. This sample included IO men (n = 106) treated with tamoxifen citrate (10 mg b.i.d.) and testosterone undecanoate (40 mg t.i.d.) or placebo (n = 106) and normozoospermic men (n = 82) serving as controls. Outcome measures included sperm parameters, functional sperm fraction (FSF) and incidence of pregnancy. Analysis showed a raised frequency of high FSF values and increased area under the response curve (AURC) for FSF mean during autumn-winter seasons in patients on active treatment compared with those in placebo (P < 0.05-P < 0.04). Moreover, receiver operation characteristics (ROC) curves for a >100% FSF rise significantly discriminated autumn-winter from other seasons (P < 0.001, all), whereas active treatment showed higher than placebo FSF values particularly during autumn and winter (P < 0.001, all). The pregnancy incidence was higher in the autumn in all groups. It is concluded that FSF values showed a better response to active treatment during autumn and winter, indicating that commencement of empirical treatment at this time in IO men may stand a better chance to succeed.