Semen evaluation following preparation for in vitro fertilization of human oocytes.

Semen preparation is an important step of in vitro fertilization (IVF) and can affect the success of this procedure. Prior to oocyte insemination, spermatozoa are washed to remove seminal plasma which is believed to contain decapacitation factors. This study was undertaken to evaluate the effect of preparation on semen quality and subsequent successful IVF. Oocytes were recovered from 12 hMG/hCG-stimulated women by laparoscopy, and 6 h later semen specimens were obtained from the male partners. After liquefaction, 1 ml of semen was centrifuged twice in Ham's F10 medium supplemented with 10% of homologous serum, and the final suspension was used to inseminate the preovulatory eggs. In the initial and washed-sperm suspensions, motility was evaluated by the MEP method, and the occurrence of acrosome reaction and sperm viability were evaluated by the triple-stain technique. Fertilization was documented by the formation of two pronuclei. Washing caused a significant decrease in the percentage of motile sperm from 68% to 59% but significantly increased mean sperm velocity from 26 to 29 micron/sec (p less than 0.01). The mean fertilization rate was 65%, and no correlation was found with any of the parameters of semen quality before or after washing. Semen preparation for IVF is associated with a decrease in the percentage of motile sperm that does not seem to affect the fertilizing ability of normal spermatozoa but may be of importance in patients with abnormal semen.