Micromanipulation of gametes for male factor infertility.
Review
Overview
abstract
Techniques such as PZD, SZI, and ICSI are advantageous in cases of extreme male factor infertility. They are adjunctive techniques, applicable in the laboratory only during an IVF cycle. They can be used either simultaneously on sibling oocytes or, if indicated, individually. The present results demonstrate a lack of correlation between quantitative sperm parameters and outcome of assisted fertilization procedures. Preliminary results strongly suggest that ICSI will replace SZI and PZD for treatment of severe male factor infertility. Hundreds of viable pregnancies have been established well below the normal cut-off values for regular assisted conception procedures. Fertilization and pregnancy occurred following the use of spermatozoa without progressive motility and without normal morphology. In some patients sperm counts were correspondingly reduced and spermatozoa could be visualized only after centrifugation of the semen specimen. The current results provide evidence that spermatozoa from extremely oligoasthenoteratozoospermic men can produce normal offspring after the application of micromanipulation techniques, even when fertilization previously failed following standard IVF. Currently, investigators have not been able to identify, on the basis of conventional semen evaluations, subgroups of patients who would not benefit from microsurgical techniques. Findings published to date suggest approximately 24% clinical pregnancy rates per cycle when SZI and PZD are used together, but 35% clinical pregnancy rate per cycle for ICSI. Preliminary results suggest that the application of these techniques does not increase the risk of birth defects for subsequent offspring. However, continued observation of the potential effects of these procedures on progeny will be required.
