Fertilization, pregnancy and embryo implantation rates after ICSI in casesof obstructive and non-obstructive azoospermia

The aetiology of azoospermia can be grossly divided into obstructive and no n-obstructive causes, Although in both cases testicular spermatozoa can be used to treat male fertility, it is not well established whether success ra tes following intracytoplasmic sperm injection (ICSI) are comparable. There fore, a retrospective analysis of fertilization, pregnancy and embryo impla ntation rates was performed following ICSI with testicular spermatozoa in o bstructive or non-obstructive azoospermia, In total, 193 ICSI cycles were c arried out with freshly retrieved testicular spermatozoa; in 139 cases of o bstructive and 54 cases of non-obstructive azoospermia, The fertilization r ate after ICSI with testicular spermatozoa in non-obstructive azoospermia w as significantly lower than in obstructive azoospermia (67.8% versus 74.5%; P = 0.0167). Within the non-obstructive group, the fertilization rate in t he group of maturation arrest (47.0%) was significantly lower than in case of Sertoli cell-only (SCO) syndrome (71.2%) or germ cell hypoplasia (79.5%) . Embryo quality on day 2 after ICSI was similar for all groups. Pregnancy rates per transfer between obstructive (36.8%) and non-obstructive groups ( 36.7%) were similar. In cases of maturation arrest the pregnancy rate per t ransfer was lowest (20.0%) although not significantly different from SCO sy ndrome or hypoplasia groups. Embryo implantation rates were not different b etween the obstructive (19.6%) and nonobstructive groups (25.8%), and were lowest in cases of germ cell hypoplasia (15.8%). This retrospective analysi s shows that although fertilization rate after ICSI with testicular spermat ozoa in non-obstructive azoospermia is significantly lower than in obstruct ive azoospermia, pregnancy and embryo implantation rates are similar.