A low total motile sperm count in donor sperm obtained from commercial banks does not affect pregnancy rates from intrauterine insemination

Objective

Women are often concerned about the absolute quantity and quality of sperm in a thawed donor sample at the time of intrauterine insemination (IUI). The aim of this study was to determine how the total motile sperm count (TMSC) of donor sperm obtained from commercial sperm banks affects the pregnancy rate after IUI.

Study design

We performed a retrospective cohort study including single women and women in same-sex relationships undergoing IUI at a single academic fertility center between January 2011 and March 2018. Our primary outcome was pregnancy rates per IUI cycle, stratified by post-washed TMSC. The data was analyzed according to TMSC and included three different groups: samples with a TMSC less than 5 million; TMSC of 5–10 million; and a TMSC greater than 10 million. Pregnancies were defined by a serum Beta-human chorionic gonadotropin (Beta-HCG) of greater than 5 mIU/mL. Chi-squared analyses and correlation coefficients were performed.

Results

Overall, 9341 IUIs were conducted during the study period. Of these, 1080 (11.56%) were performed for single women and women in a same-sex relationship using commercially available donor sperm. We found that there were no differences in the pregnancy rates per insemination based on TMSC. The pregnancy rates per cycle were 15/114 (13.3%) for the group with a TMSC of less than 5 million; 34/351(9.5%) with a TMSC of 5–10 million; and 61/609 (10.0%) for samples with a TMSC greater than 10 million (p = 0.52). We found an insignificant correlation (r = −0.072) between donor sperm TMSC and pregnancy after IUI (p = 0.46). Furthermore, a reassuring beta-HCG level (>100IU/L) drawn 16 days after IUI was unrelated to TMSC (r = 0.0071, p = 0.94).

Conclusion

The pregnancy rate following IUI is unaffected by the TMSC of commercially available donor sperm. This result is useful in reassuring patients when freshly thawed donor sperm is found to have a lower TMSC. Frozen sperm samples from commercial banks typically represent just a portion of an ejaculate produced by a donor who meets the banks’ standards for age, health and sperm quality. As such, exaggerated sperm death caused by freezing does not result in worse outcomes with donor sperm.