Selection of embryos for day-3 transfer at the pronuclear-stage and pronuclear-stage cryopreservation results in high delivery rates in fresh and frozen cycles.

PURPOSE: Evaluate IVF-ET outcome data for a unique culture and cryopreservation strategy. METHODS: Retrospective study of 92 patients. Embryos for day-3 transfer were selected at pronuclear-stage; all extra zygotes were cryopreserved at pronuclear-stage. RESULTS: Delivery rates for Anonymous Oocyte Donation (Group I), patients <35 years (Group II), and 35-38 years (Group III) were 52.9%, 61.5%, and 51.7% for fresh and 38.5%, 33.3%, and 40.0% for frozen transfer. Deliveries per retrieval were 82.3%, 71.8%, and 58.6%. Only 0.88, 0.80, and 0.61 more zygotes were cultured than what were used for fresh transfer. Singleton, twin, and triplet rates were 64.6%, 31.2%, and 4.2% for fresh and 69.2%, 30.8%, and 0% for frozen. CONCLUSIONS: Selection of day-3 transfer embryos at the pronuclear-stage and cryopreservation of extra zygotes results in high delivery rates in fresh and frozen cycles. This approach optimizes deliveries per retrieval and provides many patients with more than one pregnancy per retrieval.

Vitrification versus programmable rate freezing of late stage murine embryos: a randomized comparison prior to application in clinical IVF.

A prospective randomized trial was performed to compare post-thaw development of murine blastocysts following programmable rate freezing and two methods of vitrification. Frozen 2-cell murine embryos (n = 429) thawed and cultured for 48 h, were randomly allocated by stage of development into four groups: control (not refrozen), programmable rate freezing (PR) in 0.25 ml straws, vitrification in flexible micropipettes by immersion in super-cooled (VSC) liquid nitrogen (LN2), and vitrification in flexible micropipettes by immersion in LN2 (VLN). Survival, developmental stage progression, presence or absence of an inner cell mass (ICM), and cell counts were recorded 24 h post-thaw. All measured outcomes were different between embryos from the control group and all freezing methods. Controlled-rate freezing resulted in the lowest total cell counts and fewest embryos with a distinct ICM. A higher percentage of embryos survived 24 h post-thaw, progressed to more advanced developmental stages and had higher total cell counts after VLN compared with PR. Moreover, fewer embryos, frozen by either PR or VSC, contained a detectable ICM compared with VLN. These data demonstrate that vitrification may be a better method for freezing murine blastocysts than PR, and may prove to be a superior method for freezing human blastocysts.

Equivalent blastocyst rates after freezing murine embryos in Cryo Bio System high security or standard instruments-medicine-veterinarian straws.

OBJECTIVE: To validate the Cryo Bio System (CBS) straw in our current cryopreservation system before using it in clinical practice. DESIGN: A prospective comparison of blastocyst development rates in 278 murine embryos after refreezing and thawing at the two-cell stage against the standard Instruments-Medicine-Veterinarian (IMV) straw used in our cryopreservation program. SETTING: Private IVF laboratory. PATIENT(S): No human subjects or material was used in this study. INTERVENTION(S): Frozen two-cell murine embryos were thawed and randomized into three treatments [1] refreezing in the CBS straws, [2] refreezing in IMV 0.25-mL straws, and [3] control embryos remaining in culture without refreezing. Embryos were refrozen using identical cryoprotectants and identical programmed controlled-rate freezers. After cryopreservation, straws were held in liquid nitrogen for a brief period before thawing and continued culture. MAIN OUTCOME MEASURE(S): Postthaw murine blastocyst development rate. RESULT(S): When the manufacturer's filling and loading protocol was used for the CBS straw there was no significant difference in the blastocyst development rate between CBS (75.0%) and IMV (76.4%) straws. CONCLUSION(S): The CBS straw may be a viable and potentially safer alternative for cryopreservation of human embryos, particularly for patients with known infections.

Development of a new and efficient laboratory method for processing testicular sperm.

PURPOSE: Testicular biopsy specimens contain large amounts of debris that makes sperm pick-up for ICSI more difficult than with epididymal aspirates. We sought to develop improved processing techniques for testicular sperm extraction (TESE). METHODS: Retrievals were with azoospermic male partner scheduled to undergo percutaneous epididymal sperm aspiration (PESA) and TESE. The study group consisted of 9 retrievals with a new TESE technique (TESE-N). The control group was 21 retrievals with PESA and 3 retrievals with a previous TESE technique (TESE-P). RESULTS: TESE-N eliminated almost all debris, which made ICSI sperm pick-up more rapid. TESE-N, PESA, and TESE-P fertilization (77, 75, and 72%) and ongoing/delivered pregnancy rates per retrieval (67, 76, and 67%) were similar. CONCLUSIONS: Our new technique provides for easy removal of debris from TESE specimens and fertilization and pregnancy rates equal to epididymal sperm's. Eliminating debris from TESE specimens allows for rapid sperm pick-up for ICSI, making the procedure more efficient for embryology staff.