FC-01 OOCYTE VITRIFICATION IS A GOOD OPTION TO PREVENT OHSS

Abstract

Aim: Ovarian hyperstimulation syndrome (OHSS) is a serious complication derived of ovarian stimulation that becomes severe in some patients. There are different ways to prevent OHSS, as cycle cancellation before HCG administration, or frozen the embryos and transfer them in a subsequent cycle and recently, a new alternative is oocyte cryopreservation. The aim of this study is to present our results of oocyte vitrification combined with GnRHa triggering as a new option to prevent OHSS. Method: From January 2008 to December 2009, a total number of 357 patients undergoing controlled ovarian stimulation for IVF in IVI Madrid showed a high response (Serum oestradiol 4000 pg/ml and/or 20 mature follicles) and underwent MII oocyte vitrification after oocyte pick up in order to carry out microinjection and embryo transfer in a natural environment afterwards. Oocytes were vitrified following the cryotop method described by Kuwayama using Kitazato (Tokyo, Japan) tools and solutions. Results: A total number of 153 cycles were performed between 2008 and 2009 in our clinic with vitrified oocytes belonging to high response stimulation cycles. The average age of the patients was 33.8±3.2, and the oocytes warmed were 11.5±4.4, with a survival rate of 82.6%. Fertilization rate was 69.4%, giving place to 6.6±3.2 embryos per patient. 1.8±0.7 embryos were transferred in 139 embryo transfers (9.2% cancellation rate). Clinical pregnancy rate was 48.2% (67 pregnancies) and there were 10 miscarriages (14.9%). Implantation rate was 27.7% (76 gestational sac/274 embryos transferred). Finally we found 57 ongoing pregnancies (41% per transfer). Conclusion: Oocyte vitrification after triggering with GnRH agonists is a highly attractive, safe, and efficient alternative to postpone embryo transfer in patients with high risk of OHSS. Our results in terms of ongoing pregnancy have made us confident in the use of this technique as routine in our laboratory. FC-02 VITRIFIED VS. SLOW-FROZEN BLASTOCYSTS: A CLINICAL AUDIT FOR 706 EMBRYOS Suzanne Cawood, Alpesh Doshi, Sarah Gotts. The Centre for Reproductive and Genetic Health, University College London, UK