OBJECTIVETo compare the clinical outcomes of fresh embryo transfer and cryopreserved-thawed embryo transfer in high-risk patients with ovarian hyperstimulation syndrome (OHSS).

METHODSWe retrospectively analyzed the clinical data of 1784 high-risk OHSS patients undergoing IVF-ET, who were divided into groups A (n=939) and B (n=845). The former received fresh embryo transfer and the latter cryopreserved-thawed embryo transfer. We compared gonadotropin (Gn) administration, body mass index (BMI), the prevalence of polycystic ovary syndrome (PCOS), the number of oocytes retrieved, and the rates of clinical pregnancy, embryo implantation and OHSS incidnece between the two groups.

RESULTSTotally, 657 (69.97%) and 586 (69.35%) pregnancies were achieved in groups A and B, respectively, with 33 cases of moderate OHSS (3.5%) in the former and 30 (3.6%) in the latter. The prevalence of PCOS, the E2 level at hCG trigger, the number of oocytes retrieved, the number of mature oocytes, and the number of quality embryos were significantly lower in group A than in B (P <0.01). No statistically significant differences were found between the two groups in age, infertility duration, BMI, Gn administration, embryo implantation rate, clinical pregnancy rate, abortion rate, and OHSS incidence (P >0.05).

CONCLUSIONIn IVF-ET cycles, cryopreserved-thawed embryo transfer does not influence the clinical outcome in high-risk OHSS patients and can avoid the incidence of severe OHSS.