Pregnancies achieved after frozen–thawed pronuclear oocytes obtained by intracytoplasmic sperm injection with spermatozoa extracted from frozen–thawed testicular tissues from non-obstructive azoospermic men

Abstract

The use of frozen-thawed testicular tissue as a source of spermatozoa for intracytoplasmic sperm injection (ICSI) in non-obstructive azoospermia yields favourable fertilization and pregnancy rates while avoiding both repetitive biopsies and unexpected cycle cancellations. Spermatozoa were obtained from frozen-thawed testicular biopsy specimens from 67 non-obstructive azoospermic men. Following fertilization, supernumerary two pronuclear (2PN) oocytes were frozen. After thawing, 17 cycles of embryo transfer were carried out with a mean number of 2.7 embryos and a mean cumulative embryo score (CES) of 18.3 per transfer. The clinical pregnancy and implantation rates per transfer in these cycles (23.5 and 8.3% respectively) were comparable to those of fresh embryo transfers (35.7 and 12.7% respectively) with a mean number of 2.7 embryos and a mean CES of 28.7 per transfer. Abortion rates, although higher with cryopreserved 2PN oocytes were not significantly different. With this approach, cryopreservation of supernumerary 2PN oocytes can be used to improve the cumulative pregnancy rates in a severely defective spermatogenetic population. To our knowledge, these are the first pregnancies reported which have been obtained by the transfer of cryopreserved pronuclear oocytes obtained from ICSI using cryopreserved testicular spermatozoa.

Efficacy of cryopreservation of embryos generated by intracytoplasmic sperm injection with spermatozoa from frozen testicular tissue

“…Both the clinical pregnancy rate (CPR) (5 % vs. 21 %) and the live birth rate (LBR) (0 % vs. 21 %) were lower for embryos generated with surgically retrieved spermatozoa than for those generated with ejaculated spermatozoa. The outcome of fresh ET and FET cycles from patients with NOA has been reported [21], and, in that report, the clinical pregnancy and implantation rates were 36 % and 13 %, respectively, in fresh ET cycles, while the clinical pregnancy and implantation rates were 24 % and 8 %, respectively, in FET cycles. Our results show that the embryo survival and cleavage rates after thawing did not differ between the TESE-FET and t-TESE-FET groups (95.7 % vs. 94.0 % and 94.3 % vs. 95.6 %, respectively).…”

“…While considerable attention has been paid to the efficacy of cryopreservation of embryos generated by ICSI with spermatozoa from frozen testicular tissue, few studies have addressed this topic. Al-Hasani et al [21] reported successful pregnancies using the transfer of frozen pronuclear-stage oocytes obtained by ICSI with spermatozoa extracted from frozen testicular tissues in patients with NOA, and embryos generated following ICSI using surgically retrieved spermatozoa from azoospermic men have also been reported [14].…”

Triggering of final oocyte maturation with gonadotropin-releasing hormone agonist or human chorionic gonadotropin. Live birth after frozen-thawed embryo replacement cycles

“…According to the center's policy, cryopreserved oocytes are first thawed and transferred at embryo stage, before a patient proceeds to treatment in a fresh cycle. Cryopreservation was performed as previously described (9). All frozen-thawed ET cycles were performed in an artificial cycle as previously described (10).…”

Frozen Embryos Generated from Surgically Retrieved Sperm from Azoospermic Men: Are They Clinically Viable?

“…The first report of FET cycles from ICSIgenerated embryos using surgically retrieved sperm for injection (frozen testicular sperm from nonobstructive azoospermic patients) was published in 1999 (22). From a total of 17 FET cycles analysed, the authors reported a CPR, ongoing pregnancy rate and IR of 23%, 17% and 8% respectively.…”

“…However, there is little in the literature assessing the outcome of FET cycles from embryos generated following ICSI using surgically retrieved sperm from azoospermic men. In the only study that reported fresh and FET cycles from a cohort of patients with non-obstructive azoospermia (22), they reported clinical pregnancy and implantation rates of 36% and 13% respectively and postthaw survival, clinical pregnancy and implantation rates of 68%, 24% and 8% respectively in the 17 FET cycles.…”