Reproductive capacity of round spermatids compared with mature spermatozoa in a population of azoospermic men

The present study aims to evaluate the injection of testicular round spermatids from patients with complete failure of spermiogenesis compared with that of mature epididymal and testicular spermatozoa. Over a period of 8 months, 188 azoospermic patients were evaluated with a view to their inclusion in our intracytoplasmic sperm injection (ICSI) programme. All patients had had a previous testicular biopsy; 38 had pure obstructive azoospermia, while 150 had non-obstructive azoospermia. Mature spermatozoa were found in 93 patients, whereas spermatozoa were entirely absent, with a predominance of round spermatids in 87. In eight patients, spermatids could not be found and therefore their cycles were cancelled. There was an early appearance of the two pronuclei stage in the round spermatid group compared with the mature spermatozoa group of patients (10.2 and 16 h respectively). The fertilization rate was also significantly lower (P = 0.00001) in the round spermatid group. The numbers of embryos developed and of embryo transfers in the round spermatid injection group were significantly lower compared with the mature spermatozoa injection group (P = 0.05 and 0.0001 respectively). No pregnancies resulted from round spermatid injection, while 18 pregnancies were achieved from the injection of mature spermatozoa. In conclusion, injection of round spermatids from patients with complete failure of spermiogenesis resulted in a significantly lower fertilization rate and a higher developmental arrest compared with injection of mature spermatozoa. With no pregnancies achieved, one may question the unusual variability of reported success rates and stress the need for further research in order to improve the outcome of this novel technique.