P–717 Where do cryopreserved embryos end up after a positive pregnancy test?

Abstract Study question What is the destination of supernumerary embryos after a positive pregnancy test? Summary answer Half of the surplus cryopreserved embryos in assisted reproduction treatments are not transferred. What is known already Many of the surpernumerary cryopreserved embryos in assisted reproductive technologies are not transferred. This is a constant issue in many fertility centers around the world. Our objective was to report what happens with vitried surplus embryos after IVF in patients with a positive pregnancy test, carrying out an analysis according to age and final evolution of the pregnancy. Study design, size, duration This is a retrospective descriptive study. We analyzed 245 embryo transfer cycles, performed between January 2013 to December 2017, in 235 patients with a positive pregnancy test and who vitrified surplus embryos. Participants/materials, setting, methods All the patients underwent treatment with their own oocytes. The variables studied were: age, miscarriage rate (MR) and live birth rate (LBR). We compared the destination of the cryopreserved embryos according to the patient’s age and pregnancy evolution. Statistical analysis was performed with Fisher’s exact test. Main results and the role of chance 20% of the IVF cycles (n = 49) were performed in women older than 40 years, 42% between 35 and 39 (n = 103) and 38% in women younger than 35 (n = 94). Average age was 35.8 ± 4.1 years. 859 embryos were cryopreserved (3.5 ± 1.9 cryopreserved embryos/patient). Average search time for surplus embryos was 20.5 ± 17.9 months, rising to 36.9 ± 14.9 months after delivery and decreasing to 8.7 ± 7.8 months after miscarriage (P