Elective cryopreservation of embryos at the blastocyst stage to prevent OHSS − High success rate and accurate patient management

P-59 Elective cryopreservation of embryos at the blastocyst stage to prevent OHSS ⴚ High success rate and accurate patient management. S. L. McKinney, G. A. Weitzman, M. R. Freeman, C. M. Whitworth, A. C. Eblen, G. A. Hill. Vanderbilt University, Nashville, TN; Nashville Fertility Center, Nashville, TN. OBJECTIVE: To determine the success of frozen embryo transfer (FET) of blastocysts from elective cryopreservation after in-vitro fertilization (IVF) cycle cancellation secondary to ovarian hyperstimulation syndrome (OHSS). DESIGN: Retrospective data analysis MATERIALS AND METHODS: Following oocyte retrieval, all patients were monitored for the development of OHSS. The transfer of blastocyst stage embryos was scheduled on embryo culture day five. If a patient developed significant symptoms due to OHSS, the embryo transfer was cancelled in an effort to mitigate the patient’s symptoms and to prevent further morbidity from OHSS. All embryos that were eligible for cryopreservation at the blastocyst stage were electively cryopreserved for future attempts at FET. The study population is comprised of all IVF patients with OHSS between January 1, 1999 and July 30, 2003 for whom the “fresh” embryo transfer was cancelled and elective cryopreservation at the blastocyst stage was performed. Only those future attempts at FET in which all embryos were derived from the referenced cohort were included in subsequent analysis (FET must be completed by 12/31/03). RESULTS: Fourteen patients were identified who met criteria for moderate to severe OHSS by both subjective and objective criteria. Two patients did not undergoing FET during the study period. Of the twelve patients that underwent FET, nine of the patients had a live birth and two patients have an ongoing third trimester pregnancy without reported complications. Cumulative chance for an ongoing pregnancy/liveborn delivery is 91.7%.

CONCLUSION: Not all patients with high serum estradiol levels and a large cohort of follicles develop clinically significant OHSS. The ability to electively cryopreserve all eligible embryos at the blastocyst stage in women who develop OHSS allows the clinician time to accurately identify those patients with moderate to severe symptoms. These patients more often require hospitalization and supportive therapy. Patients can be reassured that cancellation of their hyperstimulated cycle with subsequent FET will enhance their chance at achieving a livebirth and avoiding severe OHSS associated with pregnancy during the stimulated cycle. Supported by: None.

P-60 Increased implantation and pregnancy rates with frozen thawed blastocysts utilizing a slow re-hydration. A. Khabani, N. Klein, A. Criniti, A. Thyer, L. Scott. University of Washington, Seattle, WA. OBJECTIVE: Cryopreservation and thawing of embryos has undergone little change over time. Current conventional protocols for blastocysts utilize 2 step dehydration in glycerol and sucrose followed by slow cooling to -35– 40C and plunging into liquid nitrogen. The most common thawing protocol is a 2–3 step removal of glycerol and sucrose. Some protocols suggest that the equilibration and removal of cryoprotectant, should be performed at 370C. This report is a retrospective analysis of the data from 2 non-contemporaneous phases of a blastocyst freezing-thawing program utilizing a 2-step dehydration method and either a 2 step re-hydration or a slow, 7 step re-hydration, both performed at room temperature. DESIGN: Retrospective analysis of cycles in a university-based IVF program.

FERTILITY & STERILITY威

MATERIALS AND METHODS: Only blastocysts with a distinct inner cell mass, no atretic areas, and a clear continuous trophectoderm were frozen on Day 5 or 6. Freezing solutions, 5% glycerol and 9% glycerol ⫹ 0.2M sucrose were purchased from Sage BioPharma or prepared from Hepes-HTF with 20% HSA. Dehydration was at room temperature, 5% glycerol for 10 minutes, followed by 9% glycerol with 0.2M sucrose, blastocysts were loaded into individual straws or vials containing this solution, sealed and placed in the cryo-machine (Biogenics or Planar). The freezing curve was 3 degrees per min to -7C, hold for 10 minutes for seeding followed by slow cool to -40 C at 0.3 C/min, at which point they were plunged into liquid nitrogen. Thawing protocols used were: 1) Thaw at room T, a 3 step dilution consisting of 0.2 M sucrose (no glycerol) 0.1 M sucrose, 0.05 M sucrose for 5 minutes each and then HTF-Hepes ⫹ 20% HSA at room temperature 2) thaw at room T with dilution of glycerol and sucrose over 7 steps, removing glycerol first (3 steps) and then sucrose (4 steps). The endometrium was prepared using a standard sequential estrogenprogesterone regimen or the transfer was in a natural cycle. RESULTS: The implantation and ongoing pregnancy rates from the 2 thawing protocols were compared in matched patients (n⫽60) who had similar blastocysts frozen, and compared to the overall PR and with the endometrial preparation protocols. Survival was no different between day 5 or day 6 blastocysts and pregnancy rates no different in the 2 replacement groups. The pregnancy and implantation data is presented below. CONCLUSION: There was no difference in the numbers of blastocysts transferred in any of the groups and there was no difference in pregnancy rates between the natural and controlled cycle transfer groups. There was a significant difference (P⬍0.01) in both the pregnancy and implantation rates when matched blastocysts were thawed and re-hydrated utilizing a slow, multi-step procedure. The beneficial effects were most likely due to the protection of the inner cell mass, which is more tightly compacted and located in the internal part of the blastocyst and therefore take longer to re-hydrate. Supported by: None

ENDOMETRIOSIS P-61 Comparison of IVF-ET (in vitro fertilization-embryo transfer) outcome after various therapeutic approaches for ovarian endometriomas. B. H. Lee, H. C. Kwon, S. H. Lee, M. H. Park, B. K. Lee, J. A. Lim. Major Women’s Care Center, Seoul, Republic of Korea. OBJECTIVE: To compare controlled ovarian hyperstimulation (COH) characteristics and IVF outcome among IVF-ET patients who treated with various therapeutic modalities for ovarian endometriomas and to propose effective therapeutic modalities performing to improve outcome before IVF-ET cycle in the patients with ovarian endometriomas. DESIGN: Retrospective study. MATERIALS AND METHODS: All cases who had undergone IVF-ET after laparoscopy between January 1997 to August 2003 were reviewed. Forty eight patients with tubal factor were assigned to group I. Twenty seven, twenty two. and thirty eight patients diagnosed as severe pelvic adhesion with endometriomas by laparoscopy respectively received only medical therapy (group II), cyst aspiration (group III), and sclerotherapy (group IV). Laparoscopic cystectomy was performed in twenty patients (group V). RESULTS: As compared with group I, in group II resistance index increased (P⬍0.05) but number of oocyte, good quality oocyte ratio (mature and intermediate oocytes/total retrieval oocytes), fertilization rate, and embryo development decreased (P⬍0.05). In group III fertilization rate and embryo development decreased (P⬍0.05). There was no difference between group IV and group I in all parameters except basal FSH were increased

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