878 J Med Assoc Thai Vol. 92 No. 7 2009 Correspondence to: Petyim S, Infertility Unit, Faculty of Medicine, Siriraj Hospital, Bangkok 10700, Thailand Outcome of Sperm Preparation Using Double-Gradients Technique Study in Siriraj Hospital Somsin Petyim MD*, Roungsin Choavaratana MD*, Singpetch Suksompong MD*, Pitak Laokirkkiat MD*, Orawan Makemaharn MSc* * Infertility Unit, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand Objective: To determine the succession of sperm preparation using the double-gradients technique on sperm quality: sperm recovery rate, sperm concentration, sperm motility and percentage of post wash total motile sperm count. Study Design: Retrospective descriptive study. Settings: Infertility clinic, Faculty of Medicine, Siriraj hospital. Material and Method: During the period of January 1, 2002 through December 31, 2007, data including semen analysis before and after IUI procedure were reviewed in all male patients who were referred to the andrology laboratory for sperm washing and IUl. Comparison of semen parameters such as total sperm concentration, total motile sperm count before and after sperm preparation as well as total sperm recovery rate and total motile sperm recovery rate was evaluated. Results: After sperm preparation, both sperm concentration and progressive sperm motility significantly increased, while total motile sperm count significantly decreased. Moreover, the percentage of motile sperm recovery rate and total sperm recovery rate was higher after sperm preparation at around 59.88 + 19.26% and 34.03 + 14.58% respectively. When categorizing semen parameters to 4 groups: normozoospermia, oligozoospermia, astenozo-ospermia and oligo-astenozoospermia, sperm motility in each group, comparing with sperm motility prior preparation, significantly improved after sperm preparation. Furthermore, motile sperm recovery rate in each group significantly increased except for astenozoospermia. Total sperm recovery rate in oligozoospermia was significantly higher than normozoospermia, yet the others were significantly lower. Conclusion: Sperm preparation using double gradient percoll provided a high percentage of motile sperm recovery rate and total sperm recovery rate. It also dramatically improved progressive sperm motility in normozoospermia, oligozoospermia, astenozoospermia and oligo-astenozoospermia. Keywords: Sperm count, Sperm motility, Semen preservation Intrauterine insemination has been developed for more than 40 years (1,2) . Comparing it with other advanced reproductive technology procedures, intra- uterine insemination offers a simple, less expensive, and more acceptable treatment for infertility couples especially for treatment of male infertility problems. Until now intrauterine insemination has become one of the most widely used and is routinely performed in most assisted reproduction centers. There are many causes of male infertility which were suitable to treat by IUI such as oligozoospermia, asthenozoospermia, teratozoospermia, ejaculatory dysfunction, cervical factors, and endometriosis as well as unexplained infertility. In case of sperm cryopreservtion, which is routinely performed in many ART clinics, it provides a poor sperm quality after thawing, so IUI is an important procedure for improving and selection of the high sperm quality (3) . In addition, many previous publications presented the usefulness of this procedure and effectiveness as well. Overall pregnancy rates with IUI were around 10-20% (4-6) . Before performing intrauterine insemination, sperm preparation was J Med Assoc Thai 2009; 92 (7): 878-84 Full text. e-Journal: http://www.mat.or.th/journal