[Elective cryopreservation of all embryos in women at risk of ovarian hyperstimulation syndrome: prevention and efficiency]. / Cryopréservation de la cohorte embryonnaire en cas de risque d'hyperstimulation: prévention et efficacité.

ABSTRACT

OBJECTIVE: To evaluate the benefits, regarding prevention and clinical pregnancy rates, of embryos cryopreservation in patients at high risk of ovarian hyper-stimulation. PATIENTS AND METHODS: Retrospective study with 66 patients divided into two groups. Group 1 (n=24), cryopreservation of all the embryos due to high risk of OHSS. Group 2 (n=42), fresh embryo transfer despite of ovarian hyper-response (E2>4000/mL, hCG day). We performed a comparative analysis for group 1 and 2 regarding implantation, pregnancy, live birth and spontaneous abortion rates. RESULTS: No case of OHSS was observed in group 1 and 40.5 % in group 2. Fresh embryo transfer in group 2 gave the following results: 12.9 % implantation rate, 21.4 % pregnancy rate per transfer and 22.2 % spontaneous abortion. Identical implantation and pregnancy rates after frozen ET cycles were observed in both groups. Whereas live birth rates were significantly better in group 1 (15.4 % vs. 67 %, P=0.04) with a significant lower rate of spontaneous abortion (27 % vs. 11.4 %, P<0,01). DISCUSSION AND CONCLUSION: The negative impact of hyperestrogenic state seems to be limited to endometrial receptivity with no effect on oocyte or embryo quality. In situation of ovarian hyper-response, cryopreservation of all embryos with subsequent transfer of thawed embryos is an efficient strategy to avoid OHSS without decreasing pregnancy and live birth rates.