Factors influencing the outcome of in-vitro fertilization with epididymal spermatozoa in irreversible obstructive azoospermia.

Microsurgical epididymal sperm aspiration (MESA) and in-vitro fertilization (IVF) were found to offer limited opportunity for fatherhood to 45 men with obstructive azoospermia, due principally to poor embryo implantation. Adequate sperm preparations were obtained in 46/50 treatment cycles (92%), with the best motility found in the caput epididymis in 89% of cases. The mean fertilization rate was 11.2% and fertilization occurred in 23 cycles (50%), with embryo transfer arising from 12/26 men with vas aplasia (CAV), 4/9 with genital tract obstruction (EV) and 7/11 with irreversible vasectomy (VV). The overall implantation rate was low, 8.7% per embryo transfer (11.7% per 2-3 embryo transfers) and was not improved by Fallopian transfer. There were two pregnancies (4% per cycle), both in the EV group where embryo formation and implantation (2/4, 50% per cycle) were optimum even though sperm preparations were paradoxically inferior to the CAV and VV groups. The spermatozoa retrieved in the two successful EV cycles were appreciably blood contaminated. Analysis of the 21 failed embryo transfers showed delayed fertilization in 10 cycles, cystic fibrosis (CF) mutation or familial disease in 7/12 CAV men and the VV men were older (P < 0.001). A pregnancy which miscarried arose from a case of Young's syndrome, a carrier of CF mutation DF508. Male factors could thus be implicated in the high embryo wastage of MESA cycles and might also be influencing implantation in other IVF procedures. Where feasible, male reconstructive surgery is preferable unless fertilization can be improved, possibly by speedier retrieval techniques or by permitting sperm capacitation in vitro, but probably more effectively by micro-assisted insemination.