Comparison between mechanical freezer and conventional freezing using liquid nitrogen in normozoospermia.

Introduction: This study evaluated the effect of human semen cryopreservation using an ultra-low temperature technique with a mechanical freezer at −85°C as an alternative method to the conventional liquid nitrogen technique at −196°C. Methods: This was a prospective experimental study conducted in the Medically Assisted Conception unit, Department of Obstetrics and Gynaecology, National University Hospital, Malaysia from January 1, 2006 to April 30, 2007. All normozoospermic semen samples were included in the study. The concentration, motility and percentage of intact DNA of each semen sample were assessed before and after freezing and thawing on Days 7 and 30 post freezing.