Comparison of intravenous albumin and transfer of fresh embryos with cryopreservation of all embryos for subsequent transfer in prevention of ovarian hyperstimulation syndrome. Elective cryopreservation of all pronucleate embryos in women at risk of ovarian hyperstimulation syndrome: efficiency and safety.
To compare the efficacy of administration i.v. albumin to prevent severe ovarian hyperstimulation syndrome (OHSS) in patients undergoing ovarian stimulation for IVF with a standard policy of cryopreserving all embryos and to assess the impact of the two methods of treatment on pregnancy rates (PRs).
                Prospective randomized study.
                A tertiary referral center for assisted conception.
                Twenty-six patients undergoing IVF treatment cycles who were considered to be at high risk of developing severe OHSS on the basis of their serum E2 concentrations on the day of hCG administration and the number of oocytes collected.
                In group 1 (n = 13) all the generated embryos were cryopreserved to be transferred subsequently in hormonally manipulated cycles. In group 2 (n = 13) patients received IV infusions of albumin on the day of oocyte retrieval and 5 days later. Patients in group 2 had transfers of fresh embryos.
                The total dosage of hMG used, total number of follicles developed, number of follicles > 14 mm in diameter, serum E2 concentrations and endometrial thickness on day of hCG administration, number of oocytes retrieved, number and quality of embryos generated, PRs per cycle commenced, and onset and degree of any OHSS developed.
                There were no significant differences in the above parameters between the two groups, except for PRs that were significantly higher in patients who had all embryos cryopreserved (38.6% versus 0%).
                The policy of cryopreserving all generated embryos appears as effective as the administration of i.v. albumin in preventing OHSS in high-risk patients and produces significantly higher PRs. In a prospective randomized study, we analysed 125 patients at risk of ovarian hyperstimulation syndrome (OHSS), selected in the period between January 1996 and July 1997. All the patients had blood oestradiol concentration >/=1500 pg/ml on the day of human chorionic gonadotrophin (HCG) administration and >/=15 oocytes were collected. The patients were matched in two groups: group A, control group (n = 67), had fresh embryo transfers; group B (n = 58) had cryopreservation of all obtained pronucleate embryos. Pregnancy, live birth rates and the incidence of OHSS were compared between the two groups. There were no significant differences in terms of pregnancies per patient (46.3 versus 48.3%) and live birth rates (38. 8 versus 39.6%). No cases of OHSS occurred in group B, while four patients developed the syndrome in group A. The implantation rate was slightly but not significantly lower in group B (chi2 = 1.03). These results suggest that elective cryopreservation of all zygotes might prevent the risk of OHSS in patients undergoing IVF treatment. In contrast to what has been reported by other authors, our results show that the elective cryopreservation of zygotes does not affect pregnancy and live birth rates.
This updated of the review (D'Angelo 2002) has showed that there is insufficient evidence to support routine cryopreservation and insufficient evidence for the relative merits of intra-venous albumin versus cryopreservation.