Live birth rates after MESA or TESE in men with obstructive azoospermia: is there a difference?

STUDY QUESTION How do live birth rates compare after intracytoplasmic sperm injection (ICSI) for men with obstructive azoospermia when using sperm derived from testicular sperm extraction (TESE) versus microsurgical epididymal sperm aspiration (MESA)? SUMMARY ANSWER Our study suggests that proximal epididymal sperm (from MESA) result in higher live birth rates as compared with testicular sperm (from TESE) in couples where the man has obstructive azoospermia due to congenital bilateral absence of the vas deferens (CBAVD) or vasectomy. WHAT IS KNOWN ALREADY For couples with obstructive azoospermia, MESA (epididymal sperm) and TESE (testicular sperm) have generally been assumed to be equivalent for use in ICSI. But this assumption has never been confirmed, and this view has important clinical and basic scientific consequences. STUDY DESIGN, SIZE, DURATION This was a retrospective study of a consecutive cohort of 374 men with obstructive azoospermia and normal spermatogenesis, who underwent IVF and ICSI using either epididymal sperm or testicular sperm in the period 2000-2009. PARTICIPANTS/MATERIALS, SETTING, METHODS The study included men undergoing MESA or TESE at St. Luke's Hospital for obstructive azoospermia due to CBAVD or vasectomy. MAIN RESULTS AND THE ROLE OF CHANCE A total of 280 couples underwent MESA and 94 underwent TESE with ICSI. The live birth rate was 39% after MESA-ICSI and 24% after TESE-ICSI. The MESA-ICSI cycles also resulted in a significantly higher implantation rate and significantly higher clinical and ongoing pregnancy rates than the TESE-ICSI cycles. There was no significant difference in results between fresh or frozen sperm for both MESA and TESE. When adjusted for the available confounders, the odds ratio for live birth was significantly in favour of MESA-ICSI versus TESE-ICSI (OR 1.82; 95% CI 1.05-3.67). The only significant confounders were female age and ovarian reserve. LIMITATIONS, REASONS FOR CAUTION This is a retrospective cohort study and not a randomized clinical trial. WIDER IMPLICATIONS OF THE FINDINGS Our study suggests that some aspect of sperm maturation after the sperm leaves the testicle to enter the epididymis is required for the most optimal results, even when ICSI is used for fertilization. STUDY FUNDING/COMPETING INTERESTS No funding was used and there are no competing interests.