P–433 Pregnancy and livebirth after fertility preservation in cancer patients

Study question What do we know about pregnancy and livebirth after IVF- fertility preservation treatment in women with cancer? Summary answer Most women conceived spontaneously (60%) and more than 50% of those who returned to use their cryopreserved reproductive material have delivered at least one child. What is known already Diminishing ovarian reserve and declining future reproductive potential are important issues in cancer survivors after anti-cancer treatment exposure. Publications on pregnancy and livebirth after fertility preservation in women with cancer are sparse. Studies report most cancer patient who underwent fertility preservation do not come back and use their frozen reproductive material. The purpose of this study was to investigate the fertility preservation outcome among cancer survivors. Study design, size, duration A retrospective cohort study was conducted at a single academic fertility center from including 336 cancer patients who underwent IVF-fertility preservation from January 2009 to June 2020. Participants/materials, setting, methods We included all women with cancer aged ≤40 years old who were referred for fertility preservation treatment prior to chemotherapy. Primary outcome: Number of pregnancies and livebirths after spontaneous conception and/or using their stored frozen material. Secondary outcomes: We also evaluated the utilization rate of the stored reproductive material and mortality rate among those with follow up data. Main results and the role of chance Of 336 patients who underwent IVF-fertility preservation, 214 (63.69%) elected oocyte cryopreservation, 86 (25.5%) underwent both embryo and oocyte cryopreservation and 36 (10.7`%) underwent embryo cryopreservation. Follow up data were available in 198 (58.9%) patients with a mean follow up of 3.2 years. Of 198, 16 (8%) patients died, 40 (20%) became pregnant. Of those pregnant patients, 24 (60%) became spontaneously pregnant and 16 (40%) became pregnant after frozen oocyte or frozen embryo treatment cycles. Almost a quarter (72.5%) of the pregnancies resulted in livebirths. In total, only 23 (7%) patients had returned for frozen oocyte or frozen embryo treatment cycle, of which 16 (70%) achieved a pregnancy and 10 (63%) achieved at least one live birth. Of 142 patients who were still alive at follow up but did not get pregnant, 51 (39%) were in remission from their cancer but had not chosen to use their stored reproductive material; 44 (31%) were still on anti-cancer treatment and had not started trying yet; 13 (9%) were suffering from the end-stage cancer disease; and 7 (5%) had used their stored reproductive material but failed and stopped trying to get pregnant. Limitations, reasons for caution The main limitation was the retrospective cohort study design which could introduce unidentified selection biases. Wider implications of the findings: Of women who underwent IVF-fertility preservation for cancer, most did not come back for treatment for a variety of reasons. Of those who became pregnant, 60% conceived spontaneously. Of those who used their cryopreserved reproductive material, 63% delivered at least one child. Trial registration number 2021/6935