Seasonal variations in pre- and post-thaw donor sperm quality.
BACKGROUND
The present study was conducted to evaluate seasonal variability in the quality of pre- and post-thaw semen parameters among sperm bank donors.


METHODS
The first two consecutive ejaculates during the months March (spring, 92 males), June (summer, 97 males), September (autumn, 81 males) and December (winter, 97 males) were analysed. A comparison was made between sperm parameters from the same sperm donor at different seasons. Only males who donated semen samples during at least two seasons were enrolled in the study group (n = 103). Sperm specimens were cryopreserved in aliquots with fixed range of 8-12 x 10(6)/ml of progressive motile sperm concentration after thawing.


RESULTS
Differences between months were found in sperm concentration (P = 0.030) and normal morphology (P = 0.038); highest values were found in March and December, and the lowest in September. Mean specimen volume and percent of motile sperm cells did not vary throughout the seasons. The freezability of the donors' sperm dropped dramatically from March to September, as determined by the number of straws (fixed aliquots of 0.5 ml) and total thawed progressive motile sperm that were cryopreserved for each male (P = 0.017 and P = 0.002, respectively).


CONCLUSIONS
Cryopreservation of donor sperm is more effective during winter and spring than during the rest of the year.
Yogev
L
L
The Institute for the Study of Fertility, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, affiliated to Sackler Faculty of Medicine, Tel Aviv University, Israel. layogev@zahav.net.il
Kleiman
S
S
Shabtai
E
E
Botchan
A
A
Gamzu
R
R
Paz
G
G
Yavetz
H
H
Hauser
R
R
D000328:Adult; D015925:Cryopreservation; D006801:Humans; D008297:Male; D012621:Seasons; D012662:Semen Preservation; D013074:Sperm Banks; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*; D014019:Tissue Donors