Pre-washed frozen donor sperm is associated with lower pregnancy rates compared to semen processed immediately prior to donor insemination.

Abstract

Objective: Pre-washed frozen sperm has recently been promoted by some commercial sperm banks. The obvious benefit is reduced need for laboratory resources for physicians wishing to perform donor intrauterine insemination (IUI-D). Although many physicians would consider this a major advantage, comparison to outcome using traditional semen cryopreservation (unwashed) and post-thaw processing is very limited. The purpose of this study is to compare sperm motility parameters and cycle outcome in women undergoing intrauterine insemination (IUI) with either prewashed donor sperm or unwashed donor sperm requiring post thaw preparation. Design: Retrospective analysis of women undergoing LH timed IUI-D and FSH stimulated IUI-D with pre-washed or unwashed frozen donor sperm from January 1, 1999 through January 31, 2001. Materials/Methods: Patients undergoing donor insemination using sperm from a commercial bank (Cryobiology–Ohio) ordered pre-washed or unwashed frozen based primarily on availability. Pre-washed specimens were centrifuged over a density gradient and re-suspended in a solution of test-yolk buffer (TYB) to achieve a desired density of motile sperm prior to cryopreservation. Unwashed semen samples were diluted in TYB and centrifuged and resuspended as necessary (no density gradient) to achieve a desired density of motile sperm prior to freeze. Pre-washed specimens were thawed immediately prior to insemination requiring no further preparation. Unwashed specimens were thawed on the day of insemination, and processed via centrifugation over a density gradient just prior to IUI. All specimens were analyzed by computer assisted semen analyzer (CASA–IVOS/Hamilton Thorne) post thaw. Unwashed specimens were additionally analyzed following processing and prior to IUI. Results: Please refer to table. Results. ∗Type of cycle:Timed IUIFSH IUIType of vial:Unwashed vialsPre-washed vialsUnwashed vialsPre-washed vialsTotal number cycles:15178125Average age:32.8534.1432.7536.20Mean total progressive (M):7.868.7910.2310.14Mean progressive motility:37.97%33.11%44.63%36.06%Positive hCG:401.141Percent positive hCG:26.49%∗p < 0.5T (Timed IUI: Unwashed vs. Prewashed; Fisher’s Exact).14.10%33.33%20.00%∗ p < 0.5T (Timed IUI: Unwashed vs. Prewashed; Fisher’s Exact). Open table in a new tab Conclusions: Pre-washed semen had relatively lower percent progressive sperm motility than sperm processed post-thaw. The pregnancy rates following insemination with pre-washed sperm was markedly lower than the rates following insemination with sperm processed post thaw. Although the use of pre-washed sperm inarguably allows IUI-D to be performed by physicians with limited access to reproductive laboratories, this may come at the cost of lower fecundity. Further refinement of sperm pre-washing techniques may ultimately lead to improved outcome. At the present time, physicians with limited access to reproductive laboratories may wish to consider other alternatives to IUI with pre-washed donor sperm.