The routine assessment of sperm motility at room temperature and 37 degrees C.

The World Health Organization (WHO) laboratory manual (1992) states that assessment of sperm motility can be performed at either 37 degrees C or room temperature (20-24 degrees C). The motility of spermatozoa in 44 semen samples (22 fresh samples and 22 frozen-thawed samples) was assessed at both of these temperatures and a significant difference in the motility profiles was noted, specifically an increase at 37 degrees C in the percentage (expressed here as median and ranges) of spermatozoa with excellent progressive motility and an overall increase in the percentage with total progressive motility. With fresh samples the excellent progressive motility increased from 41 (19-53) to 54 (30-66) and the overall motility from 58.5 (39-74) to 65.0 (40-79). With the frozen-thawed samples the excellent motility increased from 14 (1-33) to 25 (6-45) and the overall motility from 30.5 (14-51) to 33.0 (16-52). As the WHO laboratory manual was published 'In response to a growing need for the standardisation of procedures for the examination of human spermatozoa' it is proposed that only one temperature for routine analysis should be used, namely 37 degrees C, which may have more physiological relevance and eliminate effects of fluctuations in ambient laboratory temperature.

The screening for cytomegalovirus antibody in semen donors and recipients within a donor insemination programme.

A total of 67 semen donors (62 Caucasian and five non-Caucasian) were tested for the presence of immunoglobulin G antibodies to cytomegalovirus (CMV). Ten (16%) of the Caucasian donors tested positive for CMV, while four (80%) of the non-Caucasian donors were positive. A total of 131 women receiving donor insemination (114 Caucasian and 17 non-Caucasian) were tested. Of these, 43 (38%) of the Caucasian recipients tested positive for CMV, while 16 (94%) of the non-Caucasian recipients were positive. There was a significant association between the incidence of positive tests and the age of the Caucasian recipients.

The cryopreservation of donor semen by a simplified method: use in an IVF and GIFT programme.

The cryopreservation of semen used in assisted reproduction procedures was carried out exclusively by a simplified method in which a mixture of semen and cryoprotectant was contained in 1-ml tuberculin syringes and plunged directly into liquid nitrogen. Donor semen samples halved and frozen in syringes and in straws in a controlled-rate freezer showed no significant difference in post-thaw motility (P = 0.217) or survival (P = 0.217) after 30 min. However, after 180 min the survival rate showed a significant reduction in syringes (P = 0.045). A significant difference (P less than 0.00008) in the rate of fertilization of oocytes was seen in IVF cycles using frozen-thawed donor sperm (58/142, 42%) when compared to fresh sperm from husbands (2315/3926, 59%). A significant reduction (P less than 0.00005) in fertilization rate was also observed in the case of supernumerary oocytes in GIFT cycles with the cryopreserved donor sperm (29/132, 22%) compared to the husbands' sperm (239/514, 46%). However, the pregnancy rate following IVF and embryo replacement was the same after fertilization with fresh sperm (75/351, 21%) as opposed to frozen sperm (3/14, 21%). Furthermore, a higher pregnancy rate was observed in GIFT with frozen donor sperm (9/19, 47%) than with fresh sperm from husbands (28/103, 27%), though this was not statistically significant (P = 0.079). These results show this simplified methods of semen cryopreservation to be effective when used in an IVF and GIFT programme, giving pregnancy rates comparable to fresh normospermic semen samples. The method is simple, quick and inexpensive.