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.

Applying clinically proven human techniques for contraception and fertility to endangered species and zoo animals: a review.

Reversible contraception that does not alter natural behavior is a critical need for managing zoo populations. In addition to reversible contraception, other fertility techniques perfected in humans may be useful, such as in vitro fertilization (IVF) or oocyte and embryo banking for endangered species like amphibians and Mexican wolves (Canis lupus baileyi). Furthermore, the genetics of human fertility can give a better understanding of fertility in more exotic species. Collaborations were established to apply human fertility techniques to the captive population. Reversible vasectomy might be one solution for reversible contraception that does not alter behavior. Reversible approaches to vasectomy, avoiding secondary epididymal disruption, were attempted in South American bush dogs (Speothos venaticus), chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla), Przewalski's horse (Equus przewalski poliakov), and Sika deer (Cervus nippon) in a variety of zoos around the world. These techniques were first perfected in > 4,000 humans before attempting them in zoo animals. In vitro fertilization with gestational surrogacy was used to attempt to break the vicious cycle of hand rearing of purebred orangutans, and egg and ovary vitrification in humans have led to successful gamete banking for Mexican wolves and disappearing amphibians. The study of the human Y chromosome has even explained a mechanism of extinction related to global climate change. The best results with vasectomy reversal (normal sperm counts, pregnancy, and live offspring) were obtained when the original vasectomy was performed "open-ended," so as to avoid pressure-induced epididymal disruption. The attempt at gestational surrogacy for orangutans failed because of severe male infertility and the lack of success with human ovarian hyperstimulation protocols. Vitrification of oocytes is already being employed for the Amphibian Ark Project and for Mexican wolves. Vasectomy can be a reversible contraception option in zoo animals, even in endangered species. Ongoing use of gamete and embryo freezing may salvage vanishing species.