Fertilization in vitro of human oocytes by spermatozoa collected in different stressful situations

It has been shown that semen quality is impaired in couples undergoing in-vitro fertilization (IVF), probably due to stress. A possible effect of stress on the ability of spermatozoa to fertilize human oocytes in vitro was analysed in the present study composed of 26 couples with normozoospermic men undergoing IVF. A semen sample was obtained during the infertility work-up and was cryopreserved (sample 1). A second sample (sample 2) was provided after oocyte retrieval during the IVF cycle. Sample 1 was thawed and both samples were washed and preincubated for oocyte insemination. One-hundred-and-five oocytes were inseminated using thawed sample 1, and 120 with sample 2. Semen parameters such as density, progressive motility and percentage of abnormal forms were compared between sample 1, before and after freezing, and sample 2. Only motility was significantly (P less than 0.01) decreased by cryopreservation in sample 1, but no parameter was significantly different when fresh sample 1 was compared to sample 2. The fertilization rate was 78.6% using sample 1 in comparison to 87.5% when sample 2 was employed (not significant, NS). Cleavage rates were 77.7 and 89.7%, respectively (NS). A group of five patients undergoing IVF who needed donor semen served as a control for the effect of sperm cryopreservation on IVF. In these cases, the donor was asked to provide a fresh sample. Half of this sample was frozen and thawed. Subsequently, fresh and thawed samples were prepared for insemination and oocytes inseminated either with the fresh preparation (n = 24) or the frozen and thawed spermatozoa (n = 22).(ABSTRACT TRUNCATED AT 250 WORDS)