Treatment of male infertility by in vitro fertilization: factors affecting fertilization and pregnancy.
IVF was attempted in more than 100 couples where the man was considered to be the cause of the infertility. 57% of all oocytes were fertilized and embryo replacement was achieved in 60-70% of cases. Pregnancies following IVF were established in cases with a long duration of infertility and different male factors such as oligospermia, teratospermia, asthenospermia and auto-immunity. Almost 50% of men with very low numbers of active spermatozoa (0.5 X 10(6)/ml motile spermatozoa) were able to establish pregnancy. No correlation was found between the percentage motility and the chance of fertilization in cases with abnormal semen, but a reduction of the incidence of fertilization was noticed in cases with extreme oligospermia (5 X 10(6)/ml) where 41% of the oocytes were fertilized. The results of the post coital hamster egg tests were inaccurate in predicting the outcome of IVF. The collection of split ejaculates, and the careful preparation of spermatozoa using sedimentation and layering methods proved to be beneficial, improving sperm motility and raising the chance of fertilization.