Experience with assisted fertilization in severe male factor infertility and unexplained failed fertilization in vitro

We present results of in-vitro fertilization (IVF) cycles usingassisted fertilization at our centre. Assisted fertilizationwas performed in those couples who had failed to fertilize oocyteswith conventional IVF, or where this was predicted by the presenceof severe male factor infertility. In 20 consecutive assistedfertilization cycles 223 oocyted were subjected exclusivelyto subzonal insemination (SUZI). Subsequently in 32 consecutiveassisted fertilization cycles 418 oocytes were subjected tointra-cytoplasmic sperm injection (ICSI). More oocytes weredamaged by ICSI (8.9%) than by SUZI (2.3%) (p = 0.03), but normalfertilization resulted more often after ICSI (56.9%) than SUZI(35.8%) (p = 0.004). Sperm parameters, other than sufficientnumbers to perform the procedures, had no effect on fertilizationor pregnancy rates. Every cycle led to the transfer of at leastone embryo. Pregnancy resulted from eight of the SUZI cycles(40%) and nine of the ICSI cycles (28%). Implantation rateswere calculated as 25 and 12% for SUZI and ICSI respectively.The presence of living spermatozoa is the only semen parameterlimiting assisted fertilization. At present more centres areable to perform SUZI than ICSI and we feel it is premature toabandon SUZI altogether. Local conditions and success ratesshould be considered when decisions are made in assisted fertilizationcycles.