Optimising human sperm use in subfertility

Abstract

Introduction: There is a nationwide shortage of sperm donors and over the last few years this has been evident at Newcastle Fertility Centre (NFC). As the most common cause for rejection of sperm donors is suboptimal semen quality, external factors that may influence semen quality (i.e. season and vitamin D) were studied to investigate their impact (if any) to improve donor recruitment. Methods: A retrospective review of donor sperm treatments at NFC between Jan 2000 and Dec 2010 was performed to investigate sperm donor shortage. A retrospective review (Dec 2006 to Nov 2009) and a longitudinal study (32 sperm donors) of the semen analyses were conducted to investigate seasonal variation in semen parameters. We performed a retrospective review of donor insemination treatments over 6 years to investigate seasonal variation in donor conceptions. The correlation between semen parameters and serum vitamin D was investigated in a cross sectional study (125 participants) and a cohort study, to examine the change in semen parameters with a rise in serum vitamin D level (with vitamin D supplementation and seasonal rise). Results: A significant reduction in the number of sperm donors recruited and a smaller pool of available donors was seen, which lead to fewer patients receiving treatment and a longer wait for treatment. Seasonal variation with improved semen parameters in winter / spring was noted, but was more prevalent in sperm donors than in patients attending NFC. However, there were no variation donor conceptions by the season of original sperm production. In the cross sectional association study there was no significant difference in the semen parameters between men with different serum vitamin D levels, however in the cohort study, semen parameters deteriorated significantly with increased serum vitamin D levels secondary to vitamin D supplementation and also seasonal rise. Conclusions: A significant local problem of sperm donor shortage is confirmed. Despite significant seasonal differences in donor semen parameters (but not donor conceptions), we do not recommend restricting recruitment of sperm donors to winter / iii spring. A negative association between vitamin D and semen parameters is noted; therefore vitamin D supplementation should not be recommended to improve to semen parameters.